Annals of the ICRP

ICRP PUBLICATION 117

Radiological Protection in Fluoroscopically

Guided Procedures Performed Outside the
Imaging Department
Editor
C.H. CLEMENT

Authors on behalf of ICRP

M.M. Rehani, O. Ciraj-Bjelac, E. Vañó, D.L. Miller, S. Walsh,
B.D. Giordano, J. Persliden

PUBLISHED FOR

The International Commission on Radiological Protection

by

Please cite this issue as ‘ICRP, 2010. Radiological Protection in

Fluoroscopically Guided Procedures Performed Outside the Imaging
Department. ICRP Publication 117. Ann. ICRP 40(6).’

1
 ICRP Publication 117

Editorial
ICRP RECOMMENDATIONS ON RADIOLOGICAL PROTECTION
IN MEDICINE

The International X-ray and Radium Protection Committee (IXRPC) was estab-
lished in Stockholm in 1928 at the Second International Congress of Radiology. The
first recommendations of this committee, adopted on 27 July 1928, deal with the pro-
tection of workers in x-ray and radium departments of hospitals (ICR, 1929). The
IXRPC was later renamed the ‘International Commission on Radiological Protec-
tion’ (ICRP); thus, ICRP was formed out of a recognised need for radiological pro-
tection in medicine.
Today, ICRP includes five standing committees, with Committee 3 being dedi-
cated solely to radiological protection in medicine. The scope of Committee 3 in-
cludes not only medical exposures (primarily to patients), but also occupational
exposures to healthcare staff, and public exposures resulting from the use of radia-
tion in medicine.
The most recent evolution of the ICRP system of radiological protection is de-
scribed in Publication 103 (ICRP, 2007a). Publication 105 (ICRP, 2007b) elaborates
on how this system applies to exposure to ionising radiation in medicine. Since Pub-
lication 105, approximately one-third of ICRP publications have dealt directly with
more specific aspects of radiological protection in medicine:
 Publication 106: Radiation dose to patients from radiopharmaceuticals (ICRP,
2008).
 Publication 112: Preventing accidental exposures from new external beam radia-
tion therapy technologies (ICRP, 2009a).
 Publication 113: Education and training in radiological protection for diagnostic
and interventional procedures (ICRP, 2009b).
 Publication 117: Radiological protection in fluoroscopically guided procedures
performed outside the imaging department (the present publication).
 Radiological protection in cardiology (ICRP, 2013).
 Radiological protection in paediatric diagnostic and interventional radiology
(ICRP, forthcoming).
In addition, several other ICRP publications in the same general field are under
development. All of this points to the fact that radiological protection in medicine
remains a major priority for ICRP.

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 ICRP Publication 117

Several of the publications referred to above, and many earlier ICRP publications
not mentioned here, focus on specific clinical settings. Organising guidance in this
way permits healthcare staff to refer to a single publication (or, at least, a small num-
ber of publications) relevant to their field of medicine.
The present publication was developed to address a number of emerging radiolog-
ical protection issues related to certain fluoroscopically guided procedures. The use
of fluoroscopy outside imaging departments is increasing rapidly; in some cases,
radiological protection considerations are lagging behind, resulting in increased risks
to healthcare staff and patients.
In addition, there have been recent reports of opacities detected in the lens of the
eye among some groups of healthcare workers using fluoroscopy in interventional
radiology and cardiology. If these effects are seen here, the potential for such effects
exists for other uses of fluoroscopy outside imaging departments. To date, this
appears to be the only circumstance where occupational exposures to ionising
radiation may be routinely resulting in clinically observable tissue reactions.
The present publication provides guidance to healthcare workers and employers
with respect to the provision of adequate training and assessment of competency,
provision of safety equipment, and quality control of fluoroscopy equipment. It also
provides guidance relevant to manufacturers of fluoroscopy equipment, suggesting
features that could be included to improve the safety of both patients and healthcare
workers.
Like all ICRP publications, the present publication aims to improve safety for
workers, patients, and members of the public.
CHRISTOPHER CLEMENT
ICRP SCIENTIFIC SECRETARY

References

ICR, 1929. International Recommendations for X-ray and Radium Protection. A Report of the Second
International Congress of Radiology. P.A. Nordstedt & Söner, Stockholm, pp. 62–73.
ICRP, 2007a. The 2007 Recommendations of the International Commission on Radiological Protection.
ICRP Publication 103. Ann. ICRP 37(2–4).
ICRP, 2007b. Radiological protection in medicine. ICRP Publication 105. Ann. ICRP 37(6).
ICRP, 2008. Radiation dose to patients from radiopharmaceuticals. ICRP Publication 106. Ann. ICRP
38(1).
ICRP, 2009a. Preventing accidental exposures from new external beam radiation therapy technologies.
ICRP Publication 112. Ann. ICRP 39(4).
ICRP, 2009b. Education and training in radiological protection for diagnostic and interventional
procedures. ICRP Publication 113. Ann. ICRP 39(5).
ICRP, 2013. Radiological protection in cardiology. ICRP Publication 120. Ann. ICRP 42(1).
ICRP, forthcoming. Radiological protection in paediatric diagnostic and interventional radiology. Ann.
ICRP.

4
 ICRP Publication 117

Radiological Protection in
Fluoroscopically Guided Procedures Performed
Outside the Imaging Department

ICRP PUBLICATION 117

Approved by the Commission in October 2011

Abstract–An increasing number of medical specialists are using fluoroscopy outside

imaging departments, but there has been general neglect of radiological protection
coverage of fluoroscopy machines used outside imaging departments. Lack of radio-
logical protection training of those working with fluoroscopy outside imaging
departments can increase the radiation risk to workers1 and patients. Procedures
such as endovascular aneurysm repair, renal angioplasty, iliac angioplasty, ureteric
stent placement, therapeutic endoscopic retrograde cholangio-pancreatography,
and bile duct stenting and drainage have the potential to impart skin doses exceeding
1 Gy. Although tissue reactions among patients and workers from fluoroscopy pro-
cedures have, to date, only been reported in interventional radiology and cardiology,
the level of fluoroscopy use outside imaging departments creates potential for such
injuries.
A brief account of the health effects of ionising radiation and protection principles
is presented in Section 2. Section 3 deals with general aspects of the protection of
workers and patients that are common to all, whereas specific aspects are covered
in Section 4 for vascular surgery, urology, orthopaedic surgery, obstetrics and gynae-
cology, gastroenterology and hepatobiliary system, and anaesthetics and pain man-
agement. Although sentinel lymph node biopsy involves the use of radio-isotopic
methods rather than fluoroscopy, performance of this procedure in operating the-
atres is covered in this report as it is unlikely that this topic will be addressed in
another ICRP publication in coming years. Information on radiation dose levels
to patients and workers, and dose management is presented for each speciality.

1
The term ‘worker’ is defined by the Commission in Publication 103 (ICRP, 2007) as ‘any person who
is employed, whether full time, part time or temporarily, by an employer, and who has recognized rights
and duties in relation to occupational radiological protection’. In this document, both terms are used:
‘worker’ in the context as above and ‘staff’ where use of ‘worker’ appears inappropriate.

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 ICRP Publication 117

Issues connected with pregnant patients and pregnant workers are covered in Sec-
tion 5. Although ICRP has recently published a report on training, specific needs
for the target groups in terms of orientation of training, competency of those who
conduct and assess specialists, and guidelines on the curriculum are provided in
Section 6.
This report emphasises that patient dose monitoring is essential whenever fluoros-
copy is used.
It is recommended that manufacturers should develop systems to indicate patient
dose indices with the possibility of producing patient dose reports that can be trans-
ferred to the hospital network, and shielding screens that can be effectively used for
the protection of workers using fluoroscopy machines in operating theatres without
hindering the clinical task.

Ó 2012 Published by Elsevier Ltd on behalf of ICRP.

Keywords: Radiological Protection; Fluoroscopy; Radiation; Dose

AUTHORS ON BEHALF OF ICRP

M.M. REHANI , O. CIRAJ -BJELAC ,

E. VAÑÓ
ANO , D.L. MILLER , S. WALSH ,
B.D. GIORDANO , J. PERSLIDEN

Reference

ICRP, 2007. The 2007 Recommendations of the International Commission on Radiological Protection.
ICRP Publication 103. Ann. ICRP 37 (2–4).

6
 CONTENTS

PREFACE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

MAIN POINTS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

1. WHAT IS THE MOTIVATION FOR THIS REPORT? . . . . . . . . . . . . . . 13

1.1. Which procedures are of concern and who is involved? . . . . . . . . . . . 13
1.2. Who has the potential to receive high radiation doses? . . . . . . . . . . . 15
1.3. Lack of training, knowledge, awareness, and skills in radiological
protection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
1.4. Patient vs occupational radiation doses . . . . . . . . . . . . . . . . . . . . . . 17
1.5. Fear and overconfidence. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
1.6. Training . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
1.7. Why this report? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
1.8. References. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19

2. HEALTH EFFECTS OF IONISING RADIATION . . . . . . . . . . . . . . . . . 21

2.1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
2.2. Radiation exposure in context. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
2.3. Health effects of ionising radiation . . . . . . . . . . . . . . . . . . . . . . . . . 22
2.4. References. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25

3. PATIENT AND OCCUPATIONAL PROTECTION . . . . . . . . . . . . . . . . 27

3.1. General methods and principles of radiological protection. . . . . . . . . 27
3.2. Requirements for the facility. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
3.3. Common aspects of patient and occupational protection . . . . . . . . . . 28
3.4. Specific aspects of occupational protection . . . . . . . . . . . . . . . . . . . . 34
3.5. References. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38

4. SPECIFIC CONDITIONS IN CLINICAL PRACTICE . . . . . . . . . . . . . . 41

4.1. Vascular surgery . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41
4.2. Urology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45
4.3. Orthopaedic surgery. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50
4.4. Obstetrics and gynaecology. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60
4.5. Gastroenterology and hepatobiliary system . . . . . . . . . . . . . . . . . . . 65
4.6. Anaesthetics and pain management . . . . . . . . . . . . . . . . . . . . . . . . . 70
4.7. Sentinel lymph node biopsy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 70
4.8. References. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 73

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 ICRP Publication 117

5. PREGNANCY AND CHILDREN . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 79

5.1. Patient exposure and pregnancy . . . . . . . . . . . . . . . . . . . . . . . . . . . 79
5.2. Guidelines for patients undergoing radiological examinations/procedures
at childbearing age. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 81
5.3. Guidelines for patients known to be pregnant . . . . . . . . . . . . . . . . . 82
5.4. Occupational exposure and pregnancy . . . . . . . . . . . . . . . . . . . . . . . 82
5.5. Procedures in children . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 83
5.6. References. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 87

6. TRAINING. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 89
6.1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 89
6.2. Curriculum . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 90
6.3. Who should be the trainer?. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 91
6.4. How much training?. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 91
6.5. Recommendations on training. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 92
6.6. References. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 93

7. RECOMMENDATIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 95

ANNEX A. DOSE QUANTITIES AND UNITS . . . . . . . . . . . . . . . . . . . . . 97

8
 PREFACE

Over the years, the International Commission on Radiological Protection (ICRP),

referred to below as ‘the Commission’, has issued many reports providing advice on
radiological protection and safety in medicine. Publication 105 (ICRP, 2007b) is a
general overview of this area. These reports summarise the general principles of
radiological protection, and provide advice on the application of these principles
to the various uses of ionising radiation in medicine and biomedical research.
At the Commission’s meeting in Oxford, UK in September 1997, steps were initi-
ated to produce reports on topical issues in medical radiological protection. It was
realised that these reports should be written in a style which is understandable to
those who are directly concerned in their daily work, and that every effort should
be taken to ensure wide circulation of such reports.
Several such reports have already appeared in print (Publications 84, 85, 86, 87, 93,
94, 97, 98, 102, 105, 112, 113 and Supporting Guidance 2) (ICRP, 2000a-d,
2001,2004a,b,2005a,b2007a,b,2009a,b).
After more than a century of use of x-rays to diagnose and treat disease, the
expansion of their use to areas outside imaging departments is much more common
today than at any time in the past.
In Publication 85 (2000b), the Commission dealt with avoidance of radiation inju-
ries from medical interventional procedures. Another ICRP publication targeted at
cardiologists is forthcoming (ICRP, 2013). Procedures performed by orthopaedic
surgeons, urologists, gastroenterologists, vascular surgeons, anaesthetists and others,
either by themselves or in conjunction with radiologists, were not covered in earlier
publications of the Commission, but there is a substantial need for guidance in this
area given the increased use of radiation and the lack of training.
The present publication is aimed at filling this need.
The membership of the Task Group was as follows:
M.M. Rehani (Chairman) E. Vañó
B.D. Giordano J. Persliden

The corresponding members were:

O. Ciraj-Bjelac D.L. Miller
S. Walsh

In addition, C. Cousins and J. Lee, ICRP Main Commission members, made

important contributions as critical reviewers.

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 ICRP Publication 117

The membership of Committee 3 during the period of preparation of this report

was:
E. Vañó (Chairman) H. Ringertz S. Mattsson
M.R. Baeza Y. Yonekura K.Å. Riklund
L.T. Dauer M.M. Rehani (Secretary) M. Rosenstein
J.W. Hopewell J.M. Cosset B. Yue
P. Ortiz López I. Gusev
D.L. Miller P.-L. Khong

References

ICRP, 2000a. Pregnancy and medical radiation. ICRP Publication 84. Ann. ICRP 30(1).
ICRP, 2000b. Avoidance of radiation injuries from medical interventional procedures. ICRP Publication
85. Ann. ICRP 30(2).
ICRP, 2000c. Prevention of accidental exposures to patients undergoing radiation therapy. ICRP
Publication 86. Ann. ICRP 30(3).
ICRP, 2000d. Managing patient dose in computed tomography. ICRP Publication 87. Ann. ICRP 30(4).
ICRP, 2001. Radiation and your patient: a guide for medical practitioners. ICRP Supporting Guidance 2.
Ann. ICRP 31(4).
ICRP, 2004a. Managing patient dose in digital radiology. ICRP Publication 93. Ann. ICRP 34(1).
ICRP, 2004b. Release of patients after therapy with unsealed radionuclides. ICRP Publication 94. Ann.
ICRP 34(2).
ICRP, 2005a. Prevention of high-dose-rate brachytherapy accidents. ICRP Publication 97. Ann. ICRP
35(2).
ICRP, 2005b. Radiation safety aspects of brachytherapy for prostate cancer using permanently implanted
sources. ICRP Publication 98. Ann. ICRP 35(3).
ICRP, 2007a. Managing patient dose in multi-detector computed tomography (MDCT). ICRP
Publication 102. Ann. ICRP 37(1).
ICRP, 2007b. Radiological protection in medicine. ICRP Publication 105. Ann. ICRP 37(6).
ICRP, 2009a. Preventing accidental exposures from new external beam radiation therapy technologies.
ICRP Publication 112. Ann. ICRP 39(4).
ICRP, 2009b. Education and training in radiological protection for diagnostic and interventional
procedures. ICRP Publication 113. Ann. ICRP 39(5).
ICRP, 2013. Radiological protection in cardiology. ICRP Publication 120. Ann. ICRP 42(1).

10
 MAIN POINTS

 An increasing number of medical specialists are using fluoroscopy outside imaging

departments, and expansion of its use is much greater today than at any time in the past.
 There has been general neglect of radiological protection coverage of fluoroscopy
machines used outside imaging departments.
 Lack of radiological protection training of workers using fluoroscopy outside imaging
departments can increase the radiation risk to workers and patients.
 Although tissue reactions among patients and workers from fluoroscopy procedures have,
to date, only been reported in interventional radiology and cardiology, the level of fluo-
roscopy use outside imaging departments creates potential for such injuries.
 Procedures such as endovascular aneurysm repair, renal angioplasty, iliac angioplasty,
ureteric stent placement, therapeutic endoscopic retrograde cholangio-pancreatography,
and bile duct stenting and drainage have the potential to impart skin doses exceeding 1 Gy.
 Radiation dose management for patients and workers is a challenge that can only be met
through an effective radiological protection programme.
 Patient dose monitoring is essential whenever fluoroscopy is used.
 Medical radiation applications on pregnant patients should be justified and tailored to
reduce fetal dose.
 Termination of pregnancy at fetal doses of <100 mGy is not justified based upon radia-
tion risk.
 The restriction of a dose of 1 mSv to the embryo/fetus of a pregnant worker after decla-
ration of pregnancy does not mean that it is necessary for a pregnant woman to avoid
work with radiation completely, or that she must be prevented from entering or working
in designated radiation areas.
 Pregnant medical workers may work in a radiation environment provided that there is
reasonable assurance that the fetal dose can be kept below 1 mSv during the course of
pregnancy. It does, however, imply that the employer should review the exposure condi-
tions of pregnant women carefully
 Every action to reduce patient dose will have a corresponding impact on occupational
dose, but the reverse is not true.
 Recent reports of opacities in the eyes of workers who use fluoroscopy have drawn atten-
tion to the need to strengthen radiological protection measures for the eyes.
 The use of radiation shielding screens for protection of workers using x-ray machines in
operating theatres is recommended, wherever feasible.
 A training programme in radiological protection for healthcare professionals has to be
oriented towards the type of practice in which the target audience is involved.
 A worker’s competency to carry out a particular function should be assessed by individ-
uals who are suitably competent themselves.
 Periodic quality control testing of fluoroscopy equipment can provide confidence in equip-
ment safety.
 Manufacturers should develop systems to indicate patient dose indices with the possibility
of producing patient dose reports that can be transferred to the hospital network.
 Manufacturers should develop shielding screens that can be effectively used for the pro-
tection of workers using fluoroscopy machines in operating theatres without hindering the
clinical task.

11
 1. WHAT IS THE MOTIVATION FOR THIS REPORT?

 An increasing number of medical specialists are using fluoroscopy outside imaging

departments, and expansion of its use is much greater today than at any time in the past.
 There has been general neglect of radiological protection coverage of fluoroscopy
machines used outside imaging departments.
 Lack of radiological protection training of workers using fluoroscopy outside imaging
departments can increase the radiation risk to workers and patients.
 Recent reports of opacities in the eyes of workers who use fluoroscopy have drawn atten-
tion to the need to strengthen radiological protection measures for the eyes.

1.1. Which procedures are of concern and who is involved?

(1) After more than a century of the use of x rays to diagnose and treat disease, the
expansion of their use to areas outside imaging departments is much more common
today than at any time in the past. The most significant use of x rays outside radi-
ology has been in interventional procedures, predominantly in cardiology, but there
are also a number of other clinical specialities where fluoroscopy is used to guide
medical or surgical procedures.
(2) In Publication 85 (ICRP, 2001), the Commission dealt with the avoidance of
radiation injuries from medical interventional procedures. Another ICRP publica-
tion targeted at cardiologists is forthcoming (ICRP, 2013). Procedures performed
by orthopaedic surgeons, urologists, gastroenterologists, vascular surgeons, anaes-
thetists (or anaesthesiologists), and others, either by themselves or in conjunction
with radiologists, were not covered in earlier publications of the Commission, but
there is a substantial need for guidance in this area in view of the increased use of
radiation and the lack of training. Practices vary widely across the world, as does
the role of radiologists. In some countries, radiologists play a major role in such pro-
cedures. These procedures and the medical specialists involved are listed in Table 1.1,
although the list is not exhaustive.
(3) These procedures allow medical specialists to treat patients and achieve the de-
sired clinical objective. In many situations, these procedures are less invasive, result
in decreased morbidity and mortality, are less costly, and result in shorter hospital
stays than the alternative surgical procedures, or may be the best alternative if the
patient cannot have an open surgical procedure. In some situations, these procedures
may be the only alternative, particularly for very elderly patients.
(4) In addition to fluoroscopy procedures outside imaging departments, this report
also addresses sentinel lymph node biopsy (SLNB), which uses radiopharmaceuticals
as a radiation source rather than x rays. It was deemed appropriate to cover this in
this report as it is unlikely that this topic will be addressed in another ICRP publi-
cation in coming years, and the topic requires attention from the radiological protec-
tion angle.

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 ICRP Publication 117

Table 1.1. Examples of common procedures (not exhaustive) that may be performed in or outside imaging
departments (adapted from NCRP, 2011).
Organ system or region Procedure
Bones, joints, or musculoskeletal Fracture/dislocation reduction
Specialities: Implant guidance for anatomical localisation, orientation,
 Radiology and fixation
 Orthopaedics Deformity correction
 Neurosurgery Needle localisation for injection, aspiration, or biopsy
 Anaesthesiology Anatomical localisation to guide incision location
 Neurology Adequacy of bony resection
Foreign body localisation
Biopsy
Vertebroplasty
Kyphoplasty
Embolisation
Tumour ablation
Nerve blocks
Diagnostic (ipsilateral femoral neck/shaft fracture)
Intramedullary nailing
Kirshner wire/external fixator pin placement
Percutaneous hardware placement
Ligament reconstruction
Trauma
Level confirmation
Cyst aspiration
Radiofrequency ablation
Assessment of limb alignment/joint line
Gastrointestinal tract Percutaneous gastrostomy
Specialities: Percutaneous jejunostomy
 Radiology Biopsy
 Gastroenterology Stent placement
Diagnostic angiography
Embolisation
Kidney and urinary tract Biopsy
Specialities: Nephrostomy
 Radiology Ureteric stent placement
 Urology Stone extraction
Tumour ablation
Intravenous pyelography/urography
Cystometrography
Cystography
Excretion urography
Urethrography
Percutaneous nephrolithotomy
Extracorporeal shock wave lithotripsy
Kidney stent insertion

14
 Radiological Protection in Fluoroscopically Guided Procedures Performed Outside the Imaging Department

Table 1.1. (continued)

Organ system or region Procedure
Liver and biliary system Biopsy
Specialities: Percutaneous biliary drainage
 Radiology Endoscopic retrograde cholangio-pancreatography
 Gastroenterology Percutaneous cholecystostomy
Stone extraction
Stent placement
Transjugular intrahepatic portosystemic shunt
Chemo-embolisation
Tumour ablation
Percutaneous transhepatic cholangiography
Bile duct drainage
Reproductive tract Specialities: Hysterosalpingography
 Radiology Embolisation
 Obstetrics and gynaecology Pelvimetry
Vascular system Specialities: Diagnostic venography
 Radiology Angioplasty
 Cardiology Stent placement
 Vascular surgery Embolisation
 Nephrology Stent-graft placement
Venous access
Inferior vena cava filter placement
Endovascular aneurysm repair
Central nervous system Specialities: Diagnostic angiography
 Radiology Embolisation
 Neurosurgery Thrombolysis
 Neurology
Chest Biopsy
Specialities: Thoracentesis
 Radiology Chest drain placement
 Vascular surgery Pulmonary angiography
 Internal medicine Pulmonary embolisation
Thrombolysis
Tumour ablation

1.2. Who has the potential to receive high radiation doses?

(5) For many years, it was a common expectation that people who work full time
in departments where radiation is used on a daily basis need to have radiological
protection training and monitoring of their radiation doses. These departments in-
clude radiotherapy, nuclear medicine, and diagnostic radiology. As a result, many
national regulatory authorities had the notion that if they looked after these facili-
ties, they had fulfilled their responsibilities for radiological protection. In many
countries, this is still the situation. However, the use of x rays for diagnostic or inter-
ventional procedures outside these departments has increased markedly in recent
years. Fluoroscopy machines are of particular concern because of their potential
for causing relatively high exposures of workers or patients. There are examples of
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 ICRP Publication 117

countries where national authorities have no idea about how many fluoroscopy ma-
chines exist in operating theatres outside the control of imaging departments. Work-
ers in radiotherapy facilities either work away from the radiation source or only
work near heavily shielded sources. As a result, in normal circumstances, occupa-
tional radiation exposure is typically minimal. Even if radiation is always present
in nuclear medicine facilities, overall exposure of workers can still be less than the
exposure for those who work near an x-ray tube, as the intensity of radiation from
x-ray tubes is very high. The situation in imaging [radiography and computed
tomography (CT)] is similar, in the sense that workers normally work away from
the radiation sources, and are based at consoles that are shielded from the x-ray radi-
ation source. On the other hand, working in a fluoroscopy room typically requires
that workers stand near the x-ray source (both the x-ray tube itself and the patient,
who is a source of scattered x rays). The radiation exposure of workers in fluoros-
copy rooms can be more than the exposure of those working in radiotherapy or nu-
clear medicine, or those working in imaging who do not work with fluoroscopic
equipment. The actual dose depends upon the time spent in the fluoroscopy room
(when the fluoroscope is being used), the shielding garments used (lead apron, thy-
roid and eye protection), the mobile ceiling-suspended screen and other hanging lead
flaps that are employed, as well as equipment parameters. In general, for the same
amount of time spent in radiation work, the radiation exposure of workers in a fluo-
roscopy room will be higher than that of workers who do not work in a fluoroscopy
room. If medical procedures require large amounts of radiation from lengthy fluo-
roscopy or multiple images, such as in vascular surgery, these workers may receive
substantial radiation doses and therefore need a higher degree of radiological protec-
tion through the use of appropriate training and protective tools. The use of fluoros-
copy for endovascular repair of straightforward abdominal and thoracic aortic
aneurysms by vascular surgeons is increasing, and radiation levels are similar to
those in interventional radiology and interventional cardiology. Over the next few
years, the use of more complex endovascular devices, such as branched and fenes-
trated stents for the visceral abdominal aorta and the arch and great vessels, is likely
to increase. These procedures are long and complex, requiring prolonged fluoro-
scopic screening. They also often involve extended periods during which the entrance
surface of the radiation remains fixed relative to the x-ray tube, increasing the risk of
skin injury. Image-guided injections by anaesthetists for pain management is also
increasing.

1.3. Lack of training, knowledge, awareness, and skills in radiological protection

(6) In many countries, non-radiologist professionals work with fluoroscopy with-

out direct support from their colleagues in radiology, using equipment that may
range from fixed angiographic facilities, similar to an imaging department, to mobile
image intensifier fluoroscopy systems. In most cases, physicians using fluoroscopy
outside the imaging department (orthopaedic surgeons, urologists, gastroenterolo-
gists, vascular surgeons, gynaecologists, anaesthetists, etc.) have either minimal or
no training in radiological protection, and may not have regular access to those
16
Radiological Protection in Fluoroscopically Guided Procedures Performed Outside the Imaging Department

professionals who do have training and expertise in radiological protection, such as

medical physicists. Radiographers/technologists working in these facilities outside
radiology or cardiology departments may only be familiar with one or two specific
fluoroscopy units used in the facility. Thus, their skills, knowledge, and awareness
may be limited. Nurses in these facilities typically have limited skills, knowledge,
and awareness of radiological protection. The lack of radiological protection culture
in these settings adds to patient and occupational risk.

1.4. Patient vs occupational radiation doses

(7) It has commonly been believed that occupational radiological protection is

much more important than patient protection. The underlying bases for this belief
are that: (1) workers are likely to work with radiation for their entire career, (2) pa-
tients undergo radiation exposure for their own benefit, and (3) patients are only ex-
posed to radiation for medical purposes a few times in their life. While the first two
bases still hold, the situation with regard to the third point has changed drastically in
recent years. Patients are undergoing examinations and procedures many times.
Moreover, the types of examinations that patients undergo nowadays involve higher
doses compared with several decades ago. Radiography was the mainstay of inves-
tigation in the past. In recent years, CT has become very common. A CT scan im-
parts a radiation dose to the patient that is equivalent to several hundreds of
radiographs. In the past, fluoroscopic examinations were largely diagnostic, whereas
nowadays, a larger number of fluoroscopic procedures are interventional and these
impart a higher radiation dose to patients. An increase in the frequency of use of
higher dose procedures per patient has been reported (NCRP, 2009). Many patients
receive radiation doses that exceed the typical occupational dose that workers may
receive during their entire career.
(8) According to the latest UNSCEAR report, the average annual dose (world-
wide) for occupational exposure in medicine is 0.5 mSv/year (UNSCEAR, 2010).
For a person working for 45 years, the total dose may be 22.5 mSv over their full
working life. The emphasis on occupational radiological protection in the past cen-
tury has yielded excellent results, as evidenced by the above figure, and occupational
doses seem well under control. However, there are examples of very poor adoption
of personal monitoring measures in many countries among those covered in this
report.
(9) It is unfortunate that, particularly in clinical areas covered in this report, radio-
logical protection of patients has not received much attention. Surveys conducted by
the IAEA among non-radiologists and non-cardiologists from over 30 developing
countries indicate that there is an almost complete (in over 90% of situations) lack
of patient dose monitoring (IAEA, 2010). Surveys of the literature indicate a lack
of reliable data on occupational doses in settings outside imaging departments. This
needs to be changed.

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 ICRP Publication 117

1.5. Fear and overconfidence

(10) In the absence of knowledge and awareness, people tend to either overesti-
mate or underestimate risk. Either they have unfounded fears or they have a disre-
gard for appropriate protection. It is common practice for young medical residents
to observe how their seniors deal with situations. They start with inquisitive minds
about radiation risks, but if they find that their seniors are not greatly concerned
about radiological protection, they tend to slowly lose interest and enthusiasm. This
is not uncommon among the clinical specialists covered in this report. If residents do
not have access to medical physicist experts, which is largely the case, they follow the
example of their seniors, leading to fear in some cases and disregard in others. This is
an issue of radiation safety culture, and propagation of an appropriate safety culture
should be considered the responsibility of senior medical staff.

1.6. Training

(11) Historically, in many hospitals, x-ray machines were only located in imaging
departments, so non-radiologists who performed procedures using this equipment
had radiologists and radiographers/technologists available for advice and consulta-
tion. In this situation, there was typically some orientation of non-radiologists in
radiological protection based on practical guidance. With time, as the use of radia-
tion increased and x-ray machines were installed in other departments and areas of
the hospital, outside the control of imaging departments, the absence of training has
become evident and needs attention. In surveys conducted by the IAEA in training
courses for non-radiologists and non-cardiologists (http://rpop.iaea.org/RPOP/
RPoP/Content/AdditionalResources/Training/2_TrainingEvents/Doctorstrain-
ing.htm), it is clear that most non-radiologists and non-cardiologists in developing
countries have not undergone training in radiological protection, and that medical
meetings and conferences of these specialists typically include no lectures on, or com-
ponent of, radiological protection. This lack of training in radiological protection
poses risks to workers and patients, and needs to be corrected. The Commission rec-
ommends that the level of training in radiological protection should be commensu-
rate with the use of radiation (ICRP, 2009).

1.7. Why this report?

(12) The use of radiation is increasing outside imaging departments. The fluoros-
copy equipment is becoming more sophisticated and can deliver higher radiation
doses in a short time; therefore, fluoroscopy time alone is not a good indicator of
radiation dose. There is a near absence of patient dose monitoring in the settings
covered in this report. Overexposures from digital x-ray equipment may not be de-
tected, machines that are not tested under a quality control system can give higher
radiation doses and poor image quality, and repeated radiological procedures in-
crease cumulative patient radiation doses. There are a number of image quality fac-
tors that, if not taken into account, can deliver poor-quality images and a higher
18
 Radiological Protection in Fluoroscopically Guided Procedures Performed Outside the Imaging Department

radiation dose to patients. On the other hand, there are simple techniques that use
the principles of time, distance, and shielding (Sections 3 and 4) to help ensure the
safety of both patients and workers. Lessons drawn from other situations, not di-
rectly involving fluoroscopy machines outside radiology, demonstrate that both acci-
dental exposures and routine overexposures can occur, resulting in undesirable
health effects of ionising radiation for patients and workers (ICRP, 2001; Ciraj-
Bjelac et al., 2010; Vañó et al., 2010; http://www.nytimes.com/2010/08/01/health/
01radiation.html?_r=3&emc=eta1). Radiation shielding screens and flaps are lacking
in many fluoroscopy machines used in operating theatres, and radiological protec-
tion workers outside radiology and cardiology departments face specific problems.
Personal dosimeters are not used by some professionals or their use is irregular.
As a consequence, occupational doses in several practices are largely unknown.

1.8. References

Ciraj-Bjelac, O., Rehani, M.M., Sim, K.H., et al., 2010. Risk for radiation induced cataract for staff in
interventional cardiology: is there reason for concern? Catheter. Cardiovasc. Interv. 76, 826–834.
IAEA, 2010. Radiation Protection of Patients. IAEA, Vienna. Available at: http://rpop.iaea.org (last
accessed 14.02.2011).
ICRP, 2001. Avoidance of radiation injuries from medical interventional procedures. ICRP Publication
85. Ann. ICRP 30(2).
ICRP, 2009. Education and training in radiological protection for diagnostic and interventional
procedures. ICRP Publication 113. Ann. ICRP 39(5).
ICRP, 2013. Radiological protection in cardiology. ICRP Publication 120. Ann. ICRP 42(1).
NCRP, 2009. Ionizing Radiation Exposure of the Population of the United States. NCRP Report 160.
National Council on Radiation Protection and Measurements, Bethesda, MD.
NCRP, 2011. Radiation Dose Management for Fluoroscopically Guided Interventional Medical
Procedures. NCRP Report 168. National Council on Radiation Protection and Measurements,
Bethesda, MD.
UNSCEAR, 2010. Sources and Effects of Ionizing Radiation. UNSCEAR 2008 Report. United Nations,
New York.
Vañó, E., Kleiman, N.J., Duran, A., et al., 2010. Radiation cataract risk in interventional cardiology
personnel. Radiat. Res. 174, 490–495.

19
 2. HEALTH EFFECTS OF IONISING RADIATION

 Although tissue reactions among patients and workers from fluoroscopy procedures have,
to date, only been reported in interventional radiology and cardiology, the level of fluo-
roscopy use outside imaging departments creates potential for such injuries.
 Patient dose monitoring is essential whenever fluoroscopy is used.

2.1. Introduction

(13) Most people, health professionals included, do not realise that the intensity of
radiation from an x-ray tube is typically hundreds of times higher than that from
radioactive substances (radio-isotopes and radiopharmaceuticals) used in medicine.
This lack of understanding has been partially responsible for the lack of radiological
protection among many users of x rays in medicine. The level of radiological protec-
tion practice tends to be better in facilities using radioactive substances. For practical
purposes, this report is concerned with the health effects of ionising radiation from x
rays, which are electromagnetic radiation like visible light, ultra violet light, infra-red
radiation, radiation from mobile phones, radio waves, and microwaves. The major
difference is that these other types of electromagnetic radiation are non-ionising
and dissipate their energy through thermal interaction (dissipation of energy through
heat). This is how microwave diathermy and microwave ovens work. On the other
hand, x rays are forms of ionising radiation – they may interact with atoms and
can cause ionisation in cells. They may produce free radicals or direct effects that
can damage DNA or cause cell death.

2.2. Radiation exposure in context

(14) As a global average, the natural background radiation in terms of effective

dose is 2.4 mSv/year (UNSCEAR, 2010). In some countries, typical background
radiation is approximately 1 mSv/year, and in other countries, it is approximately
3 mSv/year. There are some areas in the world, (e.g. India, Brazil, Iran) where the
population is exposed to background radiation levels in terms of effective dose of
5–15 mSv/year. The Commission has recommended a whole-body effective dose limit
for workers of 20 mSv/year (averaged over a defined 5-year period; 100 mSv in
5 years) and other limits as shown in Table 2.1 (ICRP, 2007, 2012).
(15) It must be emphasised that individuals who work with fluoroscopy machines
and use the radiological protection tools and methods described in this report can
keep their radiation dose from work with x rays to less than or around 1 mSv/year;
thus, there is a role for radiological protection.

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 ICRP Publication 117

Table 2.1. Occupational dose limits (ICRP, 2007, 2012).

Type of limit Occupational limit
Effective dose 20 mSv/year, averaged over a defined 5-year period
Annual equivalent dose in:
Lens of the eye 20 mSv
Skin 500 mSv
Hands and feet 500 mSv

2.3. Health effects of ionising radiation

(16) Health effects of ionising radiation are classified into two types: those that are
visible, documented, and confirmed within a relatively short time (weeks to a year or
so) [called ‘tissue reactions’ or (formerly) ‘deterministic effects’: skin erythema, hair
loss, cataract, infertility, circulatory disease]; and those that are only estimated and
may take years or decades to manifest (called ‘stochastic effects’: cancer and genetic
effects).

2.3.1. Tissue reactions

(17) Tissue reactions have thresholds that are typically quite high (Table 2.2). For
workers, these thresholds are not normally reached when good radiological protec-
tion practices are used. For example, skin erythema used to occur in the hands of
workers a century ago, but this has rarely happened in the last 50 years or so in
workers using medical x rays. There are a large number of reports of skin injuries
among patients from fluoroscopic procedures in interventional radiology and cardi-
ology (ICRP, 2001; Balter et al., 2010), but none, to date, in other areas of fluoros-

Table 2.2. Thresholds for tissue reactions (ICRP, 2007).

Tissue and effect Threshold
Total dose in a Annual dose in the case
single exposure (Gy) of fractionated exposure (Gy/year)
Testes
Temporal sterility 0.1 0.4
Permanent sterility 6.0 2.0
Ovaries
Sterility 3.0 >0.2
Lens
Cataract (visual impairment) 0.5 0.5 divided by years of duration
Bone marrow
Depression of haematopoiesis 0.5 >0.4
Heart or brain
Circulatory disease 0.5 0.5 (total dose for fractionated exposure)

22
Radiological Protection in Fluoroscopically Guided Procedures Performed Outside the Imaging Department

copy use. Hair loss has been reported on the legs of interventional radiologists and
cardiologists in the area unprotected by the lead apron or lead table shield (Wiper
et al., 2005; Rehani and Ortiz López, 2006), but has not been reported in orthopaedic
surgery, urology, gastroenterology, or gynaecology because x rays are used to a les-
ser extent in these specialities. Although there is a lack of information regarding
these injuries in vascular surgeons, these specialists use large amounts of radiation,
and their exposure can match that of interventional cardiologists or radiologists.
This creates the potential for tissue reactions in both patients and workers. Infertility
is unlikely at the dose levels encountered in radiation work in fluoroscopy suites or
even in interventional laboratories.
(18) The lens of the eye is one of the more radiosensitive tissues in the body (ICRP,
2012). Radiation-induced cataracts have been demonstrated among workers in-
volved with interventional procedures using x rays (Vañó et al., 1998; ICRP,
2001). A number of studies have suggested that there may be a substantial risk of
lens opacities in populations exposed to low doses of ionising radiation. These in-
clude patients undergoing CT scans (Klein et al., 1993), astronauts (Cucinotta
et al., 2001; Rastegar et al., 2002), radiological technologists/radiographers (Chodick
et al., 2008), atomic bomb survivors (Nakashima et al., 2006; Neriishi et al., 2007),
and those exposed in the Chernobyl accident (Day et al., 1995).
(19) Until recently, cataract formation was considered to be a tissue reaction
with a threshold for detectable opacities of 5 Sv for protracted exposures and
2 Sv for acute exposures (ICRP, 2001, 2012). The Commission continues to rec-
ommend that optimisation of protection should be applied in all exposure situa-
tions and for all categories of exposure. With the recent evidence, the
Commission further emphasises that protection should be optimised not only
for whole-body exposures, but also for exposures to specific tissues, particularly
the lens of the eye, the heart, and the cerebrovascular system. The Commission
has now reviewed recent epidemiological evidence suggesting that there are some
tissue reaction effects, particularly those with very late manifestation, where
threshold doses are or may be lower than previously considered. For the lens
of the eye, the threshold in absorbed dose is now considered to be 0.5 Gy. Also,
although uncertainty remains, medical practitioners should be made aware that
the absorbed dose threshold for circulatory disease may be as low as 0.5 Gy to
the heart or brain. For occupational exposure in planned exposure situations,
the Commission now recommends an equivalent dose limit for the lens of the
eye of 20 mSv/year, averaged over a defined 5-year period, with no single year
exceeding 50 mSv (ICRP, 2012).
(20) If doctors and workers remain near the x-ray source and within a high scatter
radiation field for several hours per day, and do not use radiological protection tools
and methods, the risk may become substantial. Two recent studies conducted by the
IAEA have shown a higher prevalence of lens changes in the eyes of interventional
cardiologists and nurses working in cardiac catheterisation laboratories compared to
the control group (Ciraj-Bjelac et al., 2010; Vañó et al., 2010).

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 ICRP Publication 117

2.3.2. Stochastic effects

(21) Stochastic effects include cancer and genetic effects, but the scientific evidence
for cancer in humans is stronger than that for genetic effects. According to Publica-
tion 103 (ICRP, 2007), the detriment-adjusted nominal risk coefficient for stochastic
effects for the whole population after exposure to radiation at a low dose rate is
5.5%/Sv for cancer and 0.2%/Sv for genetic effects. Therefore, carcinogenic effects
are 27 times more likely than genetic effects. To date, there have been no documented
cases of radiation-induced genetic effects in humans, even in survivors of Hiroshima
and Nagasaki. All of the literature on genetic effects comes from non-human species,
where the effects have been documented in thousands of papers. As a result, and
after careful review of many decades of literature, the Commission reduced the tissue
weighting factor for the gonads by more than half from 0.2 to 0.08 (ICRP, 2007).
Thus, emphasis is placed on cancer in this report.
(22) Cancer risks are estimated on the basis of probability, and are derived mainly
from the survivors of Hiroshima and Nagasaki. Therefore, these risks are estimated
risks. With the current state of knowledge, carcinogenic effects are more likely for
organ doses of >100 mGy. For example, a chest CT scan that yields approximately
8 mSv effective dose can deliver approximately 20 mGy dose to the breast; five CT
scans will therefore deliver approximately 100 mGy. There may be controversies
about cancer risk at the radiation dose from one or a few CT scans, but the doses
encountered from five to 15 CT scans approach the exposure levels where risks have
been documented. As radiation doses to patients from fluoroscopic procedures vary
greatly, one must determine the dose to get an approximate idea of the cancer risk. It
must be mentioned that cancer risk estimates are based on models of a nominal stan-
dard human, and cannot be considered to be valid for a specific individual person.
As stochastic risks have no threshold, and the Commission considers that the linear
no-threshold relationship of dose effect is valid down to any level of radiation expo-
sure, the risk, however small, is assumed to remain even at very low doses. The best
way to achieve protection is to optimise exposures, keeping radiation exposure as
low as reasonably achievable, commensurate with clinically useful images.

2.3.3. Individual differences in radiosensitivity

(23) It is well known that different tissues and organs have different radiosensitiv-
ities, and that females are generally more radiosensitive than males to cancer induc-
tion. The same is true for young patients (increased radiosensitivity) compared with
older patients. For example, the lifetime attributable risk of lung cancer for a woman
after an exposure of 0.1 Gy at 60 years of age is estimated to be 126% higher than
that for a man exposed to the same dose at the same age (BEIR, 2006). If a man
is exposed to radiation at 40 years of age, his risk of lung cancer is estimated to
be 17% higher than if he was exposed to the same radiation dose at 60 years of
age. These general aspects of radiosensitivity should be taken into account in the
process of justification and optimisation of radiological protection in fluoroscopi-
cally guided procedures because, in some cases, the radiation dose level may be rel-
24
 Radiological Protection in Fluoroscopically Guided Procedures Performed Outside the Imaging Department

atively high for several organs. There are also individual genetic differences in sus-
ceptibility to radiation-induced cancer, and these should be considered in specific
cases involving higher doses based on family and clinical history (ICRP, 1999).
(24) Pre-existing auto-immune and connective tissue disorders predispose patients
to the development of severe skin injuries in an unpredictable fashion. The cause is
not known. These disorders include scleroderma, systemic lupus erythematosus, and
possibly rheumatoid arthritis, although there is controversy regarding whether sys-
temic lupus erythematosus predisposes patients to these effects. Genetic disorders
that affect DNA repair, such as the defect in the ATM gene responsible for ataxia
telangiectasia, also predispose individuals to increased radiation sensitivity. Diabetes
mellitus, a common medical condition, does not increase sensitivity to radiation, but
does impair healing of radiation injuries (Balter et al., 2010).

2.4. References

Balter, S., Hopewell, J.W., Miller, D.L., et al., 2010. Fluoroscopically guided interventional procedures: a
review of radiation effects on patients’ skin and hair. Radiology 254, 326–341.
BEIR, 2006. Committee to Assess Health Risks from Exposure to Low Levels of Ionizing Radiation.
Health Risks from Exposure to Low Levels of Ionizing Radiation: BEIR VII Phase 2. National
Academies Press, Washington, DC.
Chodick, G., Bekiroglu, N., Hauptmann, M., et al., 2008. Risk of cataract after exposure to low doses of
ionizing radiation: a 20-year prospective cohort study among US radiologic technologists. Am. J.
Epidemiol. 168, 620–631.
Ciraj-Bjelac, O., Rehani, M.M., Sim, K.H., et al., 2010. Risk for radiation induced cataract for staff in
interventional cardiology: is there reason for concern? Catheter. Cardiovasc. Interv. 76, 826–834.
Cucinotta, F.A., Manuel, F.K., Jones, J., et al., 2001. Space radiation and cataracts in astronauts. Radiat.
Res. 156, 460–466.
Day, R., Gorin, M.B., Eller, A.W., 1995. Prevalence of lens changes in Ukrainian children residing around
Chernobyl. Health Phys. 68, 632–642.
ICRP, 1999. Genetic susceptibility to cancer. ICRP Publication 79. Ann. ICRP 28(1/2).
ICRP, 2001. Avoidance of radiation injuries from medical interventional procedures. ICRP Publication
85. Ann. ICRP 30(2).
ICRP, 2007. The 2007 Recommendations of the International Commission on Radiological Protection.
ICRP Publication 103. Ann. ICRP 37(2–4).
ICRP, 2012. ICRP statement on tissue reactions / early and late effects of radiation in normal tissues and
organs – threshold doses for tissue reactions in a radiation protection context. ICRP Publication 118.
Ann. ICRP 41(1/2).
Klein, B.E., Klein, R., Linton, K.L., et al., 1993. Diagnostic X-ray exposure and lens opacities: the Beaver
Dam Eye Study. Am. J. Public Health 83, 588–590.
Nakashima, E., Neriishi, K., Minamoto, A., et al., 2006. A reanalysis of atomic-bomb cataract data,
2000–2002: a threshold analysis. Health Phys. 90, 154–160.
Neriishi, K., Nakashima, E., Minamoto, A., et al., 2007. Postoperative cataract cases among atomic
bomb survivors: radiation dose response and threshold. Radiat. Res. 168, 404–408.
Rastegar, N., Eckart, P., Mertz, M., 2002. Radiation-induced cataract in astronauts and cosmonauts.
Graefes Arch. Clin. Exp. Ophthalmol. 240, 543–547.
Rehani, M.M., Ortiz López, P., 2006. Radiation effects in fluoroscopically guided cardiac interventions –
keeping them under control. Int. J. Cardiol. 109, 147–151.
UNSCEAR, 2010. Sources and Effects of Ionizing Radiation. UNSCEAR 2008 Report. United Nations,
New York.

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 ICRP Publication 117

Vañó, E., González, L., Beneytez, F., et al., 1998. Lens injuries induced by occupational exposure in non-
optimized interventional radiology laboratories. Br. J. Radiol. 71, 728–733.
Vañó, E., Kleiman, N.J., Duran, A., et al., 2010. Radiation cataract risk in interventional cardiology
personnel. Radiat. Res. 174, 490–495.
Wiper, A., Katira, A., Roberts, D.H., 2005. Interventional cardiology: it’s a hairy business. Heart 91,
1432.

26
 3. PATIENT AND OCCUPATIONAL PROTECTION

 Manufacturers should develop systems to indicate patient dose indices with the possibility
to produce patient dose reports that can be transferred to the hospital network.
 Manufacturers should develop shielding screens that can be used for the protection of
workers using fluoroscopy machines in operating theatres without hindering the clinical
task.
 Every action to reduce patient dose will have a corresponding impact on occupational
dose, but the reverse is not true.
 Periodic quality control testing of fluoroscopy equipment can provide confidence in equip-
ment safety.
 The use of radiation shielding screens for protection of workers using x-ray machines in
operating theatres is recommended, wherever feasible.

3.1. General methods and principles of radiological protection

(25) The basic principles of radiological protection are justification, optimisation,

and dose limits. Time, distance, and shielding form the key aspects of methods to
achieve optimisation as applicable to the situations within the scope of this report.

3.1.1. Time

(26) The duration of radiation use should be minimised. This is effective whether
the object of minimisation is fluoroscopy time or the number of frames or images
acquired.

3.1.2. Distance

(27) Distance from the x-ray source should be as much as is practical (this can re-
duce the radiation dose by a factor of 2–20 or more) (see Section 3.3.2 and Fig. 3.3).

3.1.3. Shielding

(28) Shielding should be used effectively. It is most effective as a tool for occupa-
tional protection (Section 3.4.1), and has a limited role for protecting patients’ body
parts, such as the breasts, female gonads, eyes, and thyroid, in fluoroscopy (with the
exception of male gonads).

3.1.4. Justification

(29) The benefits of many procedures that use ionising radiation are well estab-
lished and well accepted by the medical profession and society at large. When a pro-
cedure involving radiation is medically justifiable, the anticipated benefits are almost
always identifiable and are sometimes quantifiable. On the other hand, the risk of
adverse consequences is often difficult to estimate and quantify. In Publication

27
 ICRP Publication 117

103, the Commission stated as a principle of justification that ‘Any decision that al-
ters the radiation exposure situation should do more good than harm’ (ICRP,
2007a). The Commission has recommended a multi-step approach to justification
of patient exposures in Publication 105 (ICRP, 2007b). In the case of the individual
patient, justification normally involves both the referring medical practitioner (who
refers the patient and may be the patient’s physician/surgeon) and the radiological
medical practitioner (under whose responsibility the examination is conducted).

3.1.5. Optimisation

(30) Once examinations are justified, they must be optimised (i.e. can they be done
at a lower dose while maintaining efficacy and accuracy?). Optimisation of the pro-
tection should be generic for the examination type and all the equipment and proce-
dures involved. It should also be specific for the individual, and consideration should
be given to whether or not it can be effectively done in a way that reduces dose for
the particular patient (ICRP, 2007b).

3.2. Requirements for the facility

(31) Practice varies worldwide and there should be compliance with requirements
laid down by national authorities. Typically, each x-ray machine should be registered
with the appropriate state database under the overall oversight of national regula-
tory authority. Frequently, during the process of registration and authorisation,
the authority will examine the specifications of the machine and the room where it
is going to be used in terms of size and shielding. At international level, safety
requirements for x-ray machines have been provided by international organisations
such as the International Electrotechnical Commission and the International Stan-
dards Organization. In many countries, there are national standards for x-ray ma-
chines which are applicable. These considerations are aimed at protection of
workers and members of the public who may be exposed. The process will also in-
clude availability of qualified staff. There are requirements for periodic quality con-
trol tests for constancy check and performance evaluation. Periodic quality control
testing of fluoroscopy equipment can provide confidence in equipment safety and its
ability to provide images of optimal image quality. If a machine is not working prop-
erly, it can provide unnecessary radiation dose to the patient and poor-quality
images. Nevertheless, whatever national requirements are, it is essential that they
are followed in order to ensure that facility design and operation is safe for patients,
workers, and the public.

3.3. Common aspects of patient and occupational protection

(32) Many common factors affect both patient and occupational doses. Every ac-
tion that reduces patient dose will also reduce occupational dose, but the reverse is
not true. Workers using lead aprons, leaded glass eyewear, or other types of shields
may reduce their own radiation dose, but these protective devices do not reduce
28
 Radiological Protection in Fluoroscopically Guided Procedures Performed Outside the Imaging Department

patient dose. In some situations, a sense of feeling safe on the part of the staff may
lead to neglect of patient protection. Therefore, involvement of the medical physicist
in patient and occupational dose optimisation and audit, particularly for higher dose
procedures, is essential. Specific factors of occupational protection are covered in
Section 3.4.

3.3.1. Patient-specific factors

Thickness of the body part in the beam

Most fluoroscopy machines adjust radiation exposure automatically through a
system called ‘automatic exposure control’. This electronic system has a sensor that
detects how much signal is being produced at the image receptor, and adjusts the x-
ray generator to increase or decrease exposure factors (typically kV, mA, and pulse
time) so that the image is of consistent quality. When a thicker body part is in the
beam, or a thicker patient is being imaged (compared with a thinner patient), the ma-
chine will automatically increase these exposure factors. The result is a similar image
quality but an increase in the radiation dose to the patient. Increased patient dose
will result in increased scatter and increased radiation dose to workers. Fig. 3.1 dem-
onstrates the increase in entrance skin dose with body part thickness, while Fig. 3.2.
shows how much radiation is absorbed in the patient’s body.

Complexity of the procedure

(33) Complexity represents the mental and physical effort required to perform a
procedure. The complexity index is an objective measure. An example would be
placement of a guide wire or catheter in an extremely tortuous vessel or across a se-
vere, irregular stenosis. Complexity is due to patient factors (anatomical variation,
body habitus) and lesion factors (location, size, severity), but is independent of oper-
ator training and experience. More complex procedures tend to require higher radi-
ation doses than less complex procedures (IAEA, 2008).

Fig. 3.1. Change in entrance surface dose (ESD) with thickness of body part in the x-ray beam for the
same image quality.

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 ICRP Publication 117

Fig. 3.2. Relative intensities of radiation on entrance and exit side of patient.

Fig. 3.3. Effect of distance between patient and x-ray tube on radiation dose to patient.

3.3.2. Technique factors

(34) The amount of radiation at the entrance surface of the body is different from
the amount of radiation that exits on the exit surface of the body. The body atten-
uates x rays in an exponential fashion. As a result, radiation intensity decreases
exponentially along its path through the body. Typically, only a small percentage
of the entrance radiation exits the body. As a result, the major risk of radiation is
on the entrance skin. Rotating the x-ray beam to avoid irradiation of the same area
of skin is helpful. A large number of skin injuries have been reported in patients
undergoing various types of interventional procedures, but to date, these injuries
have not been reported as a result of procedures conducted by orthopaedic surgeons,
urologists, gastroenterologists, and gynaecologists (ICRP, 2001; Koenig et al., 2001;
Rehani and Ortiz López, 2006; Balter et al., 2010). When using overcouch geometry,
fingers falling in the primary beam will typically receive doses that are approximately
100 times higher than those received when using undercouch geometry.
30
Radiological Protection in Fluoroscopically Guided Procedures Performed Outside the Imaging Department

(35) In addition, it is important that users understand how their equipment func-
tions, as each equipment has some unique features. The standards provided by the
National Electrical Manufacturers Association (www.nema.org) reduce the varia-
tions, but there are always features that need to be understood. The complexity of
modern equipment is such that the requirement to know your equipment should
not be compromised.

Position of the x-ray tube and image receptor

(36) The distance between the x-ray source (the x-ray tube focus) and the patient’s
skin is called the ‘source-to-skin distance’ (SSD). As the SSD increases, the radiation
dose to the patient’s skin decreases (Fig. 3.3) due to the increased distance and the
effect of the inverse square law. The patient should be as far away from the x-ray
source as practical to maximise the SSD (this may not be possible if it is necessary
to keep a specific organ or structure at the isocentre of the gantry). Once the patient
is positioned to maximise the SSD, the image receptor (image intensifier or flat panel
detector) should be placed as close to the patient as practical. All modern fluoro-
scopes automatically adjust radiation output during both fluoroscopy and fluorogra-
phy to accommodate changes in the source to image receptor distance (SID). The
radiation output adjustment by the equipment is aimed at maintaining image qual-
ity, which implies radiation dose to the image receptor and consequently to the pa-
tient (Fig. 3.4). In simplest terms, one should maximise SSD and place the detector
as close to the patient as possible. This is an important tool for the prevention of tis-
sue reactions. Mobile C-arm systems used in most cases outside imaging departments
have a constant distance between the x-ray tube and the image receptor. In this case,
as presented in Fig. 3.3, as SSD increases, the radiation dose to the patient’s skin de-
2
creases due to the inverse square law effect as ð1=SSDÞ . However, if this is not the
case, it is important to note that geometry (SSD and SID) can influence the entrance
skin dose in a complex way. If the detector is close to the patient, shifting the patient
away from the source will decrease the skin dose, but will also shift the detector away

Fig. 3.4. Effect of distance between image intensifier and patient on radiation dose to patient.

31
 ICRP Publication 117

Fig. 3.5. Effect of angulations on patient dose. PA, postero-anterior.

from the source and thus increase the skin dose. In this case, the skin dose rate varies
with the ratio ðSID=SSDÞ2 rather than with the simple inverse square law.

Avoid steep gantry angulations when possible

(37) Steep gantry angulations (steep oblique and lateral positions) increase the
length of the radiation path through the body compared with a postero-anterior
(frontal) projection (Fig. 3.5). A greater thickness of tissue must be penetrated,
and this requires higher radiation dose rates. All modern fluoroscopes adjust radia-
tion output automatically during both fluoroscopy and fluorography to accommo-
date the thickness of the body part being imaged (see Section 3.3.1). In addition
to the greater thickness, the decrease in the SSD will result in a further increase in
the skin dose. As a result, the radiation dose increases automatically when steep ob-
lique or lateral angulations are used. Whenever possible, steep oblique and lateral
gantry positions should be avoided. When these gantry positions are necessary, it
should be recognised that the radiation dose is relatively high.

Keep unnecessary body parts out of the x-ray beam

(38) It is good practice to limit the radiation field to those parts of the body that
must be imaged. When other body parts are included in the field, image artefacts
from bones and other tissues can be introduced into the image. Also, if the arms
are in the field while the gantry is in a lateral or oblique position, one arm may be
very close to the x-ray tube. The dose to this arm may be sufficiently high to cause
skin injury (Fig. 3.6). The patient’s arms should be kept outside the radiation field
unless an arm is intentionally imaged as part of the procedure.

Use pulsed fluoroscopy at a low pulse rate

(39) Pulsed fluoroscopy uses individual pulses of x rays to create the appearance of
continuous motion. At low pulse rates, this can decrease the fluoroscopy dose sub-
stantially compared with conventional continuous fluoroscopy if the dose per pulse
is constant. Pulsed fluoroscopy should always be used if it is available, with the low-

32
 Radiological Protection in Fluoroscopically Guided Procedures Performed Outside the Imaging Department

Fig. 3.6. Addition of extra tissue in the path of the radiation beam, such as an arm, increases the radiation
intensity and can cause high dose to the arm. In a lengthy procedure, this can lead to skin injury.

est pulse rate compatible with the procedure. For most non-cardiac procedures,
pulse rates of 10 pulses/s or less are adequate.

Use low fluoroscopy dose rate settings

(40) Both the fluoroscopy pulse rate and the fluoroscopy dose rate can be adjusted
in many fluoroscopy units. Fluoroscopy dose rate is not the same as fluoroscopy
pulse rate. These parameters are independent and can be adjusted separately. Lower
dose rates reduce patient dose at the cost of increased noise in the image. If multiple
fluoroscopy dose rate settings are available, the lowest dose rate setting that provides
adequate image quality should be used.

Collimation
(41) The x-ray beam should be collimated to limit the size of the radiation field to
the area of interest. This reduces the amount of tissue irradiated and also decreases
scatter, yielding a better image quality. The scatter will increase linearly with the in-
crease in the area of the radiation field. A poorly collimated primary beam, if it is
outside the patient, will significantly increase the occupational dose. When beginning
a case, the image receptor should be positioned over the area of interest, with the col-
limators almost closed. The collimators should be opened gradually until the desired
field of view is obtained. Virtual collimation (positioning of the collimators without
using radiation), available in newer digital fluoroscopy units, is a useful tool to re-
duce patient dose and should always be used if available.

Only use magnification when it is essential

(42) Electronic magnification produces relatively high dose rates at the patient’s
entrance skin. When electronic magnification is required, the least amount of mag-
nification necessary should be used.

Fluoroscopy vs image acquisition and minimisation of the number of images

(43) Image acquisition requires dose rates that are typically at least 10 times great-
er than those for fluoroscopy for cine modes, and 100 times greater than those for
33
 ICRP Publication 117

fluoroscopy for digital subtraction angiography modes. Image acquisition should

not be used as a substitute for fluoroscopy.
(44) The number of images should be limited to those necessary for diagnosis or to
document findings and device placement. If the last-image-hold fluoroscopy image
demonstrates the finding adequately and can be stored, there is no need to obtain
additional fluorography images.

Minimise fluoroscopy time

(45) Fluoroscopy should only be used to observe objects or structures in motion.
The last-image-hold image should be reviewed for study, consultation, or education
instead of continuing fluoroscopy. Short taps of fluoroscopy should be used instead
of continuous operation. It is important not to step on the fluoroscopy pedal unless
looking at the monitor screen.

Monitoring of patient dose

(46) Unfortunately, patient dose monitoring has been nearly absent in the fluoros-
copy systems that are generally available outside imaging departments. There is a
strong need to provide a means for patient dose estimation. Manufacturers should
develop systems to indicate patient dose indices with the possibility of producing pa-
tient dose reports that can be transferred to the hospital network. Professionals
should insist on this when buying new machines.

3.4. Specific aspects of occupational protection

(47) Workers can be protected by using shielding devices in addition to following

the principles in Section 3.1 and the common factors discussed in Section 3.3. Fur-
thermore, workers are typically required to have individual monitoring under na-
tional regulations in most countries.
(48) Fig. 3.7 shows relative radiation intensity near and around the patient table.
The primary source of radiation is the x-ray tube, but the patient alone should be
exposed to the primary x-ray beam. Radiation scattered from the patient, parts of
the equipment, and the patient table, so-called ‘secondary radiation’ or ‘scatter

Fig. 3.7. Primary and secondary radiation, their distribution, and relative intensity.

34
 Radiological Protection in Fluoroscopically Guided Procedures Performed Outside the Imaging Department

radiation’, is the main source of radiation exposure of workers. A useful rule of

thumb is that radiation dose rates are higher on the side of the patient closest to
the x-ray tube.

3.4.1. Shielding

Lead apron
(49) The lead apron is the most essential component of personal shielding in an
x-ray room, and must be worn by all those present. It should be noted that the level
of protection of the lead apron depends on the x-ray energy, which is represented by
the voltage applied across the x-ray tube (kV).The thicker the part of the patient’s
body falling in the x-ray beam, the higher the kV set by the fluoroscopy machine.
Higher kV means greater penetrative power of the x-ray beam, implying that greater
lead thickness is needed for attenuation.
(50) Clinical staff taking part in diagnostic and interventional procedures using
fluoroscopy wear lead protective aprons to shield tissues and organs from scattered

Fig. 3.8. Percent penetration of x rays of different kV through lead of (a) 0.5-mm thickness and (b) 0.25-
mm thickness. The result will be different for different x-ray beam filtrations. Source: E. Vañó.

35
 ICRP Publication 117

x rays (NCRP, 1995). Transmission will depend on the energies of the x rays and
lead-equivalent thickness of the aprons. The attenuation of scattered radiation is as-
sumed to be equal to that of the primary (incident) beam, and this provides a margin
of safety (NCRP, 2005).
(51) Fig. 3.8 shows the relative penetration value as a percentage of the incident
beam intensity with lead of 0.5-mm and 0.25-mm thickness. For procedures per-
formed on thinner patients, particularly children, an apron of 0.25-mm lead equiv-
alence will suffice. However, for thicker patients and with a heavy workload, a
0.35-mm lead apron may be more suitable. The wrap-around aprons of 0.25-mm
lead equivalence are ideal; these have a thickness of 0.25 mm at the back and
0.5 mm at the front. Two-piece skirt-type aprons help to distribute the weight. Heavy
aprons can pose a problem for workers who have to wear them for long periods of
time. There are reports of back injuries due to the weight of lead aprons among
workers who wear them for many years (NCRP, 2010). Some newer aprons are light
weight while maintaining lead equivalence, and have been designed to distribute the
weight through straps and shoulder flaps.

Ceiling-suspended shielding
(52) Ceiling-suspended screens that contain lead impregnated in plastic or glass are
very common in interventional radiology and cardiology suites, but are hardly ever
seen with fluoroscopy machines used in operating theatres. Shielding screens are very
effective as they have lead equivalence of 0.5 mm or more and can reduce x-ray inten-
sity by >90%. Practical problems make the use of radiation shielding screens for
occupational protection more difficult but not impossible in fluoroscopy machines
in operating theatres. Manufacturers should develop shielding screens that can be
used for occupational protection without hindering the clinical task.

Mounted shielding
(53) These can be table-mounted lead rubber flaps or lead glass screens mounted on
mobile pedestals. Lead rubber flaps are very common in most interventional radiology
and cardiology suites, but are rarely seen with fluoroscopy systems used in operating
theatres. Manufacturers are encouraged to develop detachable shielding flaps to suit
situations of practice in operating theatres. Lead rubber flaps, normally impregnated
with 0.5-mm lead equivalence, should be used as they provide effective attenuation.
(54) In addition, various types of leaded glass eyewear are commonly available.
These include eyeglasses that can be ordered with corrective lenses for individuals
who normally wear eyeglasses. There are also clip-on eye shields that can be clipped
to the spectacles of the workers, and full face shields that also function as splash
guards. Leaded eyewear should have side shields to reduce the radiation coming
from the sides. The use of these protective devices is strongly recommended.

3.4.2. Individual monitoring

(55) The principles of radiological protection of workers from ionising radiation

are discussed in Publication 75 (ICRP, 1997) and reiterated in Paragraph 113 of

36
Radiological Protection in Fluoroscopically Guided Procedures Performed Outside the Imaging Department

Publication 105 (ICRP, 2007b). In this section, practical points pertaining to who
needs to be monitored and what protective actions should be taken are discussed.
(56) Individual monitoring of workers exposed to ionising radiation using film,
thermoluminescent dosimeters, optically stimulated luminescence badges, or other
appropriate devices is used to verify the effectiveness of radiation control practices
in the workplace. The advice of a radiological protection expert/medical physicist
should be sought to determine which method is most appropriate. An individual
monitoring programme for external radiation exposure is intended to provide infor-
mation about the optimisation of protection and to demonstrate that the worker’s
exposure has not exceeded any dose limit or the level anticipated for the given activ-
ities (IAEA, 1999). As an effective component of a programme to maintain exposures
as low as reasonably achievable, it is also used to detect changes in the workplace
and identify working practices that minimise dose (NCRP, 2000; IAEA, 2004). In
1990, the Commission recommended a dose limit for workers of 20 mSv/year (aver-
aged over a defined 5-year period; 100 mSv in 5 years) and other limits as given in
Table 2.1; these limits were retained in the 2007 Recommendations (ICRP, 1991,
2007a). However, all reasonable efforts to reduce doses to the lowest possible levels
should be used. Knowledge of dose levels is essential for the use of radiological pro-
tection actions.
(57) The high occupational exposures in some situations, such as interventional
procedures performed by vascular surgeons, require the use of robust and adequate
monitoring arrangements for workers. A single dosimeter worn under the lead apron
will yield a reasonable estimate of effective dose for most instances, and another
dosimeter worn at collar level is optional. In the absence of a better way to measure
dose to the lens of the eye, a dosimeter above the apron worn on the collar closest to
the x-ray tube, usually the left collar, will provide a rough estimate of the dose to the
head and lens of the eye. In view of increasing reports of radiation-induced cataracts
in those involved in interventional procedures, monitoring the dose to the eye is
important (Ciraj-Bjelac et al., 2010; Vañó et al., 2010). Recently, eye lens dosimetry
has become an active research area. Many studies have been performed to determine
which personal dose equivalent quantity is appropriate, and how it can be used for
monitoring the dose to the lens of the eye, and to develop dosimeters to measure dose
to the lens of the eye (Domienik et al., 2011). The Commission recommends that
methods which provide reliable estimates of eye dose under practical situations
should be established. Monitoring dose to the lens of the eye at the current level
of fluoroscopy use outside imaging departments is optional for areas other than vas-
cular surgeons and interventional cardiology or equivalent. Finger dose may be
monitored using small ring dosimeters when hands are unavoidably placed in the pri-
mary x-ray beam. Finger dosimetry is optional in situations of SLNB, as the level of
radio-isotope use is small. However, the practice of fingers in the primary beam
should always be discouraged.
(58) Doses in departments should be analysed, and high doses and outliers should
be investigated (Miller et al., 2010). A risk-based approach to occupational radiation
monitoring should be adopted to avoid unnecessary monitoring of all workers. With
the current level of practice of fluoroscopy outside imaging departments in areas
37
 ICRP Publication 117

covered in this report, a single dosimeter worn under the lead apron may be adequate
except in the case of vascular surgery. There is a need to raise awareness of the need
to use a dosimeter at all times as there are many examples of infrequent use in
practice.
(59) In spite of the requirement for individual monitoring, the lack of use or irreg-
ular use of personal dosimeters is still one of the main problems in many hospitals
(Miller et al., 2010). Workers in controlled areas of workplaces are most often mon-
itored for radiation exposures. A controlled area is a defined area in which specific
protective measures and safety provisions are, or could be, required for controlling
normal exposures during normal working conditions, and preventing or limiting the
extent of potential exposures. The protection service should provide specialist advice
and arrange any necessary monitoring provisions (ICRP, 2007a). For any worker
who is working in a controlled area, or who occasionally works in a controlled area,
and may receive significant occupational exposure, individual monitoring should be
undertaken. In cases where individual monitoring is inappropriate, inadequate, or
not feasible, the occupational exposure of the worker should be assessed on the basis
of the results of monitoring the workplace and on information about the locations
and durations of exposure of the worker (IAEA, 1996). In addition to individual
monitoring, it is recommended that indirect methods using passive or electronic
dosimeters (e.g. dosimeters attached to the C-arm device) should be used in these
installations to enable the estimation of occupational doses to professionals who
do not use their personal dosimeters regularly.

3.5. References

Balter, S., Hopewell, J.W., Miller, D.L., et al., 2010. Fluoroscopically guided interventional procedures: a
review of radiation effects on patients’ skin and hair. Radiology 254, 326–341.
Ciraj-Bjelac, O., Rehani, M.M., Sim, K.H., et al., 2010. Risk for radiation induced cataract for staff in
interventional cardiology: is there reason for concern? Catheter. Cardiovasc. Interv. 76, 826–834.
Domienik, J., Brodecki, M., Carinou, E., et al., 2011. Extremity and eye lens doses in interventional
radiology and cardiology procedures: first results of the ORAMED project. Radiat. Prot. Dosim. 144,
442–447.
IAEA, 1996. International Basic Safety Standards for Protection Against Ionizing Radiation and for the
Safety of Radiation Sources. IAEA Safety Series No. 115. International Atomic Energy Agency,
Vienna.
IAEA, 1999. Assessment of Occupational Exposure Due to External Sources of Radiation. IAEA Safety
Guide RS-G-1.3. International Atomic Energy Agency, Vienna.
IAEA, 2004. Individual Monitoring. IAEA-PRTM-2 (Rev.1). International Atomic Energy Agency,
Vienna.
IAEA, 2008. Establishing Guidance Levels in X-ray Guided Medical Interventional Procedures: a Pilot
Study. IAEA Safety Report Series 59. International Atomic Energy Agency, Vienna.
ICRP, 1991. 1990 Recommendations of the International Commission on Radiological Protection. ICRP
Publication 60. Ann. ICRP 21(1–3).
ICRP, 1997. General principles for the radiation protection of workers. ICRP Publication 75. Ann. ICRP
27(1).
ICRP, 2001. Avoidance of radiation injuries from medical interventional procedures. ICRP Publication
85. Ann. ICRP 30(2).

38
 Radiological Protection in Fluoroscopically Guided Procedures Performed Outside the Imaging Department

ICRP, 2007a. The 2007 Recommendations of the International Commission on Radiological Protection.
ICRP Publication 103. Ann. ICRP 37(2–4).
ICRP, 2007b. Radiological protection in medicine. ICRP Publication 105. Ann. ICRP 37(6).
Koenig, T.R., Wolff, D., Mettler, F.A., Wagner, L.K., 2001. Skin injuries from fluoroscopically guided
procedures. I. Characteristics of radiation injury. AJR Am. J. Roentgenol. 177, 3–11.
Miller, D.L., Vañó, E., Bartal, B., et al., 2010. Occupational radiation protection in interventional
radiology: a joint guideline of the Cardiovascular and Interventional Radiology Society of Europe and
the Society of Interventional Radiology. J. Vasc. Interv. Radiol. 21, 607–615.
NCRP, 1995. Use of Personal Monitors to Estimate Effective Dose Equivalent and Effective Dose to
Workers for External Exposure to Low-LET Radiation. NCRP Report No. 122. National Council on
Radiation Protection and Measurements, Bethesda, MD.
NCRP, 2000. Radiation Protection for Procedures Performed Outside the Radiology Department. NCRP
Report No. 133. National Council on Radiation Protection and Measurements, Bethesda, MD.
NCRP, 2005. Structural Shielding Design for Medical X-ray Imaging Facilities. NCRP Report No. 147.
National Council on Radiation Protection and Measurements, Bethesda, MD.
NCRP, 2010. Radiation Dose Management for Fluoroscopically Guided Medical Procedures. NCRP
Report No. 168. National Council on Radiation Protection and Measurements, Bethesda, MD.
Rehani, M.M., Ortiz López, P., 2006. Radiation effects in fluoroscopically guided cardiac interventions –
keeping them under control. Int. J. Cardiol. 109, 147–151.
Vañó, E., Kleiman, N.J., Duran, A., et al., 2010. Radiation cataract risk in interventional cardiology
personnel. Radiat. Res. 174, 490–495.

39
 4. SPECIFIC CONDITIONS IN CLINICAL PRACTICE

 Procedures such as endovascular aneurysm repair (EVAR), renal angioplasty, iliac angi-
oplasty, ureteric stent placement, therapeutic endoscopic retrograde cholangio-pancrea-
tography (ERCP), and bile duct stenting and drainage have the potential to impart
skin doses exceeding 1 Gy.
 Radiation dose management for patients and workers is a challenge that can only be met
through an effective radiological protection programme.
 There are a number of technicalities that require involvement of or consultation with a
medical physicist. These include radiation dose assessment, dose management in day-
to-day practice, understanding of different radiation dose quantities, and estimating
and communicating risks. Effective radiological protection programmes will involve team-
work of clinical professionals with radiological protection professionals.

4.1. Vascular surgery

(60) Recent years have witnessed a paradigm shift in vascular intervention, away
from open surgery towards endovascular therapy. Endovascular therapy requires
image guidance, usually in the form of fluoroscopy. Consequently, radiation expo-
sure has increased among vascular surgical staff and patients. Radiation exposure
during EVAR is greater than that during peripheral arterial interventions such as
peripheral angioplasty (Ho et al., 2007).
(61) EVAR has gained wide acceptance for the elective treatment of abdominal
aortic aneurysms, leading to interest in similar treatment of ruptured abdominal aor-
tic aneurysms. In a recent study covering US inpatient sample data from 2001 to
2006, an estimated 27,750 hospital discharges for ruptured abdominal aortic aneu-
rysms occurred and 11.5% were treated with EVAR (McPhee et al., 2009). The
use of EVAR has increased over time (from 5.9% in 2001 to 18.9% in 2006), while
overall rates of ruptured abdominal aortic aneurysms have remained constant.
EVAR accounts for approximately half of elective aneurysm repairs performed
annually in the USA (Cowan et al., 2004). As the technology evolves, more patients
may be offered complex repairs such as fenestrated and branched grafts.
(62) Practice varies between countries. In many institutions, long-term central ve-
nous access line placement requires fluoroscopic guidance. Renal angioplasty and
iliac angioplasty are also performed by vascular surgeons at some institutions (Miller
et al., 2003a,b).

4.1.1. Levels of radiation dose

Dose to patient
(63) Endovascular therapeutic procedures require greater screening time, and
hence incur greater radiation exposure for patients and workers. The entrance skin
dose during EVAR is typically 0.85 Gy, with a range of 0.51–3.74 Gy (Weerakkody
et al., 2008). The mean dose–area product (DAP) in abdominal aortic aneurysm

41
 Table 4.1 Typical patient dose levels (rounded) from vascular surgical procedures.
Procedure Relative mean Relative mean Reported values
effective dose radiation dose
to patient to patient 

ICRP Publication 117

0 mSv 35 Fluoroscopy Entrance skin Dose–area Effective Referenceà
time (min) dose (mGy) product ðGycm2 Þ dose (mSv)
Endovascular aneurysm repair F,G 21 330–850 60–150 8.7–27 a,b
42

Venous access procedures B 1.1–3.5 8–24 2.3–4.8 1.2 c

Renal/visceral angioplasty G 20.4 1442 208 54 d,e
(stent/no stent)
Iliac angioplasty (stent/no stent) G 14.9 900 223 58 d,e
 
A, <1 mSv; B, 1–<2 mSv; C, 2–<5 mSv; D, 5–<10 mSv; E, 10–<20; F, 20–35 mSv; G, >35 mSv, based on effective dose.
à
(a) Weerakkody et al., 2008; (b) Geijer et al., 2005; (c) Storm et al., 2006; (d) Miller et al., 2003a; (e) Miller et al., 2003b.
Radiological Protection in Fluoroscopically Guided Procedures Performed Outside the Imaging Department

repair has been reported to be 1516 Gycm2 (range 520–2453 Gycm2 Þ (Weiss et al.,
2008). Routine EVAR for infrarenal aneurysm disease involves a mean effective dose
to the patient of 8.7–27 mSv (Geijer et al., 2005; Weerakkody et al., 2008). After
EVAR, patients require ongoing follow-up to ensure that the aneurysm remains ex-
cluded, and multi-slice CT remains the current standard investigation. Thus, these
patients require regular and repeated radiation exposure for life, which may have
cumulative effects. As an example, the effective dose in the first year of follow-up
has been estimated to be 79 mSv (Weerakkody et al., 2008).
(64) In interventional procedures, as well as the associated risk of cancer, there is a
possibility for skin injuries. Such injuries have been reported following a range of
fluoroscopically guided procedures (ICRP, 2001). At present, it is difficult to find
specific reports of skin injuries following EVAR. However, as surgeons undertake
more complex procedures requiring longer operating and screening times, the risk
of radiation injuries will increase (Weerakkody et al., 2008). A recent study indicated
that up to one-third of patients may receive entrance skin doses greater than 2 Gy,
the approximate threshold for transient erythema (Weerakkody et al., 2008).
(65) During abdominal aortic aneurysm repair, the mean total fluoroscopy time
has been reported to be 21 min (range 12–24 min) (Table 4.1), 92% of which (on
average) is spent in standard fluoroscopy and 8% in cinefluoroscopy (Weiss et al.,
2008). According to the technique used by these authors, approximately 49% of total
fluoroscopy time was spent in a normal field of view and 51% in a magnified view.
Peak skin dose was shown to be well correlated with DAP and body mass index,
but not with fluoroscopy time. For obese patients, peak skin dose was reported to
be twice that of non-obese patients (1.1 Gy vs 0.5 Gy, respectively) (Weiss et al.,
2008).
(66) Radiation doses from venous access procedures are low, with skin doses typ-
ically well below 1 Gy. However, these patients often require multiple repeated pro-
cedures, often within a relatively short time span (Storm et al., 2006).
(67) Typical patient doses from vascular surgical procedures are presented in
Table 4.1.
(68) The scale of 0–35 mSv for effective dose was chosen to accommodate most
procedures and keep it visually meaningful; 35 mSv has no other relevance.

Occupational dose levels

(69) There has been wide variation in reported occupational doses during EVAR.
Annual hand doses to the surgeon in terms of equivalent dose during EVAR range
from 0.2 to 19 mSv (Lipsitz et al., 2000; Ho et al., 2007). The wide variation may be
due to the use of additional free-standing and table-mounted lead shielding in some
centres. Annual body doses (in terms of effective dose) tend to be approximately
0.2 mSv and annual eye doses are approximately 1 mSv for a workload of 150 pro-
cedures/year where appropriate protective devices are used (Ho et al., 2007). The
respective mean body, eye, and hand doses of the surgeon are 7.7, 9.7, and
34.3 lSv/procedure (Ho et al., 2007).

43
 ICRP Publication 117

4.1.2. Radiation dose management

(70) With the level of radiation doses as above and the fact that many patients re-
quire follow-up examinations and procedures that involve radiation exposure, radi-
ation dose management for patients and workers is a challenge that can only be met
through an effective radiological protection programme.

Patient dose management

(71) During standard infrarenal EVAR, the radiation source (x-ray tube) is fre-
quently moved in relation to the patient. The risk of tissue reactions or stochastic
effects to the patient is minimal (see Section 2). Fenestrated or branched stent-graft
placement may require cannulation and stenting of multiple visceral branches of the
aorta. These manoeuvres may be prolonged with minimal repositioning of the x-ray
beam. Thus, there is a greater risk of tissue reactions or stochastic effects during these
procedures, particularly four-vessel fenestrated grafts. Patients should be counselled
accordingly. The need for repeat procedures for the treatment of endoleaks and the
CT scans needed for life-long surveillance for these devices will result in higher
exposures.
(72) Fluoroscopically guided venous access procedures are a common part of
interventional radiology practice. While the typical radiation dose for a single ve-
nous access case is relatively low and is reported to be below the threshold dose
for skin effects (tissue reactions) in all cases studied, these procedures are often re-
peated in the same patient within a short period of time. There is evidence that ve-
nous access procedures performed by experienced operators can result in lower
radiation doses. Thus, it is unlikely that any fluoroscopically guided venous access
procedure performed by a reasonably well-trained operator will result in sufficient
dose to cause concern for skin injury. Nevertheless, operators should remain cogni-
sant of the cumulative health effects of ionising radiation, including the potential risk
of stochastic effects (Storm et al., 2006).
(73) The dose management actions described in Section 3 are generally applicable
in vascular surgical procedures.

Occupational dose management

(74) A number of specific technique- and operator-related factors may reduce the
overall radiation dose during EVAR (Ho et al., 2007), such as:
 Operators should aim to perform a single cinematography run to confirm the
stent-graft position immediately prior to deployment. Multiple initial runs to
assess anatomy and plan stent-graft positioning are rarely necessary and should
be avoided, as they increase both patient and occupational doses.
 Hands must be kept out of the radiation beam. Leaded surgical gloves are not use-
ful for hand protection when hands are placed in the primary x-ray beam.
Although other radiological protection tools are effective, they come with draw-
backs, including physical discomfort for staff and reduced procedural efficiency.
Sterile protective surgical gloves providing radiation attenuation levels in the range
of 15–30% are available, but studies have shown that they provide minimal protec-

44
Radiological Protection in Fluoroscopically Guided Procedures Performed Outside the Imaging Department

tion when hands are placed in the primary x-ray beam for several reasons. Forward
and backscattered x rays within the glove add to hand exposure. In addition, the
presence of attenuating material within the fluoroscopy automatic brightness con-
trol region results in an increase in x-ray technique factors, exposing the hands to a
higher dose rate. These factors, coupled with the false sense of security that may
result in increased time spent in the primary beam, more than cancel out any pro-
tection that the gloves may provide. As a result, further development of new pro-
tective devices is encouraged. It is recommended that hands should be kept out of
the primary x-ray beam unless it is essential for the safety of the patient (Schueler,
2010). There is some evidence that depending on the procedure, the height of the
practitioner, and the positioning of the radiation-attenuating surgical drape, use
of this drape can substantially reduce the radiation dose to personnel with minimal
or no additional radiation exposure to the patient (King et al., 2002).
 The use of a tableside lead shield and portable lead shielding reduces the overall
effective dose to staff.
(75) In addition to the abovementioned specific items, all standard equipment fac-
tors (e.g. beam collimation, filter use, regular servicing of equipment, minimisation
of SID, field of view size) described in Section 3 may reduce occupational exposure
in vascular surgery.

4.2. Urology

(76) X rays have been used to diagnose diseases in the kidney and urinary tract for
approximately 100 years. By visualising the urinary tract, x rays are able to detect a
kidney stone or a tumour that may block urinary flow. Procedures without direct
enhancement of the urinary tract or with intravenous administration of the iodinated
contrast agent, such as intravenous pyelography (also called ‘intravenous urogra-
phy’), are normally performed by radiologists. Whenever there is direct administra-
tion of contrast agent into the urinary system, there is more active involvement of
urologists. In the past, cystography, retrograde pyelography, and voiding cystou-
rethrography were common procedures performed within radiology facilities. They
involve catheter insertion into the urethra to fill the bladder with the iodinated con-
trast medium. The fluoroscopy machine then captures images of the contrast med-
ium during the procedure to study the anatomical details or to study dynamics of
the evacuation of urine. Nowadays, intravenous pyelography is rarely performed
in many countries and has been superseded by CT. A number of procedures such
as percutaneous nephrolithotomy, nephrostomy, ureteric stent placement, stone
extraction, and tumour ablation created the need for the fluoroscopy unit to be more
easily available to urologists (in some cases, even inside the operating theatre).
(77) Furthermore, in the past few decades, lithotripsy [extracorporeal shock wave
lithotripsy (ESWL)] has become a common procedure for treating stones in the kid-
ney and ureter. Most devices developed for lithotripsy use either x rays or ultrasound
to help locate the stone(s). This works by directing ultrasonic or shock waves, cre-
ated outside the body, through skin and tissue until they hit the stones. The stones
break down into sand-like particles that can be easily passed through the urine.
45
 ICRP Publication 117

(78) Urinary and renal studies account for 16% and 1.6% of all fluoroscopically
guided diagnostic and interventional procedures, respectively, with mean effective
doses of 2 mSv for urinary procedures and 5 mSv for renal procedures. The total
contribution to collective dose is approximately 5% (NCRP, 2009).
(79) Most publications dealing with radiological protection in urology have fo-
cused on the radiation risks to the workers. Fewer studies have estimated radiation
doses to patients in urological procedures. Despite the fact that the workers work with
radiation for years whereas a patient only undergoes radiological procedures a few
times during their lifetime, it must be remembered that the workers only face scattered
radiation that is typically not more than 1% of the radiation intensity that is falling on
the patient. As workers are further protected by lead aprons, their radiation exposure
further decreases by almost 90% of the typical 1% figure. On a per-procedure basis,
this works out to approximately 0.1% of the radiation dose received by the patient.

4.2.1. Levels of radiation dose

Dose to the patient

(80) Typical dose values from urological procedures are presented in Table 4.2.
(81) Radiological studies performed for an acute kidney stone episode may include
a range of radiological procedures on patients including one or two plain kidney, uri-
nary bladder (KUB) abdominal films, one or two abdomino-pelvic CT examina-
tions, and intravenous pyelography during the first year of follow-up. The total
effective dose from such studies may be in the range of 20 to >50 mSv (Ferrandino
et al., 2009). With the increasing use of CT, there is evidence that many patients with
urolithiasis may be subjected to relatively high doses of ionising radiation during
acute stone episodes and throughout the management of their disease (Mancini
and Ferrandino, 2010). However, the appropriate use of dose management tech-
niques during diagnosis and follow-up may allow for a significant dose reduction.
(82) CT is replacing conventional radiography and intravenous urography for
evaluation of the urinary tract in many centres of the world, despite the higher radi-
ation exposure (ICRP, 2007a). When conventional and CT urography are compared,
there is evidence of a significantly higher effective dose for CT urography, even when
dose reduction strategies in CT are applied (Nawfel et al., 2004; Dahlman et al.,
2009). These findings suggest that patient dose estimates should be taken into con-
sideration when imaging protocols are established (Nawfel et al., 2004; Eikefjord
et al., 2007; ICRP, 2007a). Several studies have shown that unenhanced CT is more
accurate than excretory urography for the examination of patients with renal colic,
and is the preferred technique due to better diagnostic accuracy (Tack et al., 2003;
Eikefjord et al., 2007). In the past decade, evidence has been found of significant
dose reduction through adoption of an appropriate CT kidney stone protocol. Stud-
ies focusing on evaluation of low-dose kidney CT protocols have come to the con-
clusion that the radiation dose is comparable with that associated with excretory
urography (Tack et al., 2003; Larsen et al., 2005). Dahlman et al. (2009) reported
a 60% decrease in the effective dose to patients undergoing CT urography, from
29.9 and 22.5 mSv in 1997 to 11.7 and 8.8 mSv in 2008 for female and male patients,
46
 Radiological Protection in Fluoroscopically Guided Procedures Performed Outside the Imaging Department
Table 4.2. Typical patient dose levels (rounded) from urological procedures.
Procedure Relative mean effective Relative mean Reported values Referenceà
dose to patient radiation dose
to patient*
0 mSv 35 Fluoroscopy Entrance skin Dose area Effective
time (min) dose (mGy) product (Gycm2 Þ dose (mSv)
Intravenous urography/ C,D n.a. 3.3–42 2–42 2.1–7.9 a,b,c,d,e
intravenous pyelography
Cystometrography B n.a. / 7 1.3 b
Cystography B n.a. / 10 1.8 a,b
Excretion urography/ C n.a. / 0.43–9.9 1–3 a,b,f
micturating cysto-urethrography
Urethrography B n.a. / 6 1.1 a,b
47

Percutaneous nephrolithotomy C,D 6–12 1–250 14–29 1.9–9.2 g

Nephrostomy D 1.3–20 / 30  (5–56) 7:7y (3.4–15) a, h, i
Extracorporeal shock wave B 2.6–3.4 40–80 5 1.3–1.6 j
lithotripsy
Kidney stent insertion E / / 49 13 a
Ureteric stent placement C / / 18 4.7 a
n.a., not available.
 
Mean value.
à
(a) UNSCEAR, 2010; (b) NCRP, 2009; (c) European Commission, 2008; (d) Fazel et al., 2009; (e) Yakoumakis et al., 2001; (f) Livingstone et al., 2004; (g)
Safak et al., 2009; (h) Miller et al., 2003b; (i) McParland, 1998; (j) Sandilos et al., 2006.
* A, <1 mSv; B, 1–<2 mSv; C, 2–<5 mSv; D, 5–<10 mSv; E, 10–<20; F, 20–35 mSv;G, >35 mSv, based on effective dose.
 ICRP Publication 117

respectively. All studies concluded that considerable dose reduction is achievable

with an acceptable level of image quality. Following the principle of optimisation
of radiological protection, it is important to adapt the technical parameters on the
basis of clinical indications (ICRP, 2007a). Therefore, with improvements in technol-
ogy and optimisation of protection at the clinical level, it is expected that the ten-
dency towards dose reduction will continue in the future.
(83) The effective radiation dose to the patient in ESWL through fluoroscopy and
radiography is normally <1–2 mSv, with nearly 50–78% through fluoroscopy (Huda
et al., 1989; MacNamara and Hoskins, 1999; Sandilos et al., 2006; UNSCEAR,
2010). However, it must be remembered that the dose from ESWL is always added
to the dose from pre- and post-treatment KUB and intravenous urography proce-
dures (Sandilos et al., 2006). For other urological procedures, typical effective doses
range from <1 mSv for abdominal radiography to a mean of approximately 7 mSv
for nephrostomy.
(84) A nephrostomy tube placement is performed by placing a needle into the col-
lecting system of the kidney to provide percutaneous drainage. This procedure typ-
ically requires 10–15 min of fluoroscopy (reported range 1–56 min), and can result in
relatively high doses, particularly when tube angulation is used (NCRP, 2000; Miller
et al., 2003a). In some patients, repeated examinations may be necessary to provide
information on proper nephrostomy tube placement. Typical effective dose from
nephrostomy procedures is 7.7 mSv, with an associated range of 3.4–15 mSv (Sand-
ilos et al., 2006; UNSCEAR, 2010).

Occupational dose levels

(85) The mean effective dose to the urologist for percutaneous nephrolithotomy is
12.7 lSv/procedure (Safak et al., 2009). With an average typical workload of five pro-
cedures/week, this can imply an effective dose of 3 mSv/year to urologists. With the
above workload, the dose to the fingers can be 8–25 mGy/year (30–100 lGy/proce-
dure) and that to the region of the head and neck can be 5–10 mGy/year (20–
40 lGy/procedure), respectively (Hellawell et al., 2005). Bush et al. (1985) reported that
for an average fluoroscopy time of 25 min (range 6–75 min), the average radiation dose
received by the radiologist at collar level above the lead apron was 0.10 mSv/procedure
(range 0.02–0.32 mSv/procedure). Doses to the nurse, radiological technologist/radi-
ographer assisting with C-arm fluoroscopy, and anaesthetist were 0.04 mSv/procedure
(range 0.01–0.11 mSv/procedure), 0.04 mSv/procedure (range 0.01–0.11 mSv/proce-
dure), and 0.03 mSv/procedure (range 0.01–0.1 mSv/procedure), respectively (Bush
et al., 1985). The dose to the fingers of urologists is typically 0.27 mSv/procedure (range
0.10–2 mSv/procedure) (Bush et al., 1985; Kumari et al., 2006).
(86) Depending on the position of the x-ray tube and image detector, the radiation
dose to lower extremities can be higher than 126–167 lSv/procedure (Hellawell et al.,
2005; Safak et al., 2009). However, for a predicted annual workload of 250 cases, the
dose received is approximately 40 mSv. This may be compared with dose limits of
500 mSv to extremities (ICRP, 2007b).
(87) Based on reported dose levels in the region of the urologist’s head and neck
(0.10 mSv/procedure) (Bush et al., 1985), the radiation dose to the lens of the eye

48
Radiological Protection in Fluoroscopically Guided Procedures Performed Outside the Imaging Department

without protection for a typical workload of 250 procedures/year can be 25 mSv, and
this requires protection of the eyes in view of recent reports of lens opacities observed
in interventional cardiology staff (Ciraj-Bjelac et al., 2010; Vañó et al., 2010). With
the appropriate use of protection, occupational doses can be sufficiently low to avoid
tissue reactions. The mean equivalent dose per procedure is 33 lSv for the fingers
and 26 lSv for the eyes, and the whole-body effective dose to the urologist is
12 lSv (Safak et al., 2009). For a typical workload of 250 procedures/year, whole-
body occupational dose to personnel would reach 3 mSv, which is well below the
occupational dose limit.
(88) The above radiological protection actions are valid for all urological and renal
procedures involving x rays.

4.2.2. Radiation dose management

Patient dose management

(89) It is necessary for the urologist to weigh the anticipated clinical benefits to the
patient from the urological procedure requiring x-ray fluoroscopy against the radia-
tion risks involved. This will be in line with the Commission’s principle of justifica-
tion. Once justified, it is the responsibility of the operator to perform the procedure
using the Commission’s principle of optimisation of radiological protection using
techniques as described in this publication and other available techniques. One of
the most efficient radiological protection requirements is the avoidance of unneces-
sary examinations and procedures.
(90) Certain imaging modalities, most notably those using digital image receptors,
have shown promising decreases in patient dose while maintaining image quality.
Significant dose reduction in urethrocystography has been reported by Zoeller
et al. (1992) with the use of photostimulable phosphor plates compared with
screen-film radiography. A tube potential of 77 kVp with a phototimer was used
for screen-film radiography. Exposure parameter settings of 81 kVp and 6.4 mAs
were used to achieve sufficient image quality while using photostimulable phosphor
plates.
(91) During ESWL, radiation exposure increases with stone burden. A larger stone
requires longer treatment, with possibly more associated x rays. If unilateral radiog-
raphy of the kidney, ureter, and bladder (hemi-KUB) is performed whenever possi-
ble and appropriate during diagnosis and follow-up, the radiation exposure
associated with ESWL can be reduced significantly (Talati et al., 2000). Also, the
use of ultrasound for stone localisation could reduce patient dose significantly com-
pared with cases where x rays are used for stone localisation. Dose reduction could
be four- to five-fold, as typical effective dose levels are 0.25 mSv and 1.2 mSv for
ultrasound and x-ray localisation, respectively (MacNamara and Hoskins, 1999).
A typical ESWL procedure involves approximately 2.6–3.4 min of fluoroscopy time
and four to 26 spot films, and results in an average dose of 1.6 mSv/patient (Carter
et al., 1987; Sandilos et al., 2006). Dose reduction strategies described in Section 3
apply for all urological and renal procedures. By introducing radiological protection
actions such as reduction of the number of spot films, use of last image hold, and
49
 ICRP Publication 117

training of the operators, significant dose reduction may be obtained. The entrance
surface dose from an ESWL procedure performed by an experienced operator is
approximately 30% lower than that for a procedure performed by an inexperienced
operator (26.4 mGy vs 33.8 mGy, respectively) (Chen et al., 1991), while the reduc-
tion in the number of images results in a dose reduction of 20–62% depending on the
patient’s body mass (Griffith et al., 1989).
(92) The dose management actions described in Section 3 are generally applicable
in urological procedures.

Occupational dose management

(93) The majority of the most common procedures in urology can be performed with
little radiation exposure of workers, much below the limits prescribed by the Commis-
sion, provided that radiological protection principles, approaches, and techniques as
briefly mentioned in this publication are used. On the other hand, radiation injuries
and long-term risks are possible when radiological protection is not employed.
(94) In radiography and diagnostic CT imaging, workers are typically outside the
room and the room is well shielded. Thus, workers are exposed to a very low radi-
ation dose. However, within the operating theatre, a few staff members including the
operators are in the same room as the fluoroscopy unit, and thus they are exposed to
much higher levels of radiation. Radiation exposure of workers in the fluoroscopy
room can be significant when suitable radiological protection tools are not used.
The actual exposure depends upon the time, workload, and shielding (e.g. lead apron
and additional lead glass protective screens).
(95) For endourological procedures, dose rates to the urologist of up to 11 mSv/h
have been reported, with a dose reduction of 70–96% due to the use of fluoroscopic
drapes (Giblin et al., 1996; Yang et al., 2002). Therefore, urologists should be cog-
nisant of the radiation risk, and the concepts of time, distance, and shielding (as de-
scribed in Section 3) are critically important.
(96) At present, in many cases (except in operating theatres), overcouch x-ray tube
systems are still used for urological procedures involving x rays. The scatter radia-
tion distribution in those systems is such that radiation dose to the lens of the eye
may be relevant if eye protection is not used. Therefore, the use of undercouch sys-
tems is recommended in addition to personal protective devices for workers.

4.3. Orthopaedic surgery

(97) Orthopaedic specialities commonly use x rays as a diagnostic tool and as a

technical aid during various procedures. Despite its widespread use among orthopae-
dic surgeons, x-ray radiation and the risks associated with its use are infrequently
discussed in the orthopaedic literature.
(98) Although x rays have been used since the early 20th Century to image bones
and joints, the use of fluoroscopy for orthopaedic imaging did not gain popularity
until much later. In the 1980s, fluoroscopy gained a prominent foothold in the ortho-
paedic trauma community where it was championed as a valuable tool during fem-
oral nailing and hip pinning (Giachino and Cheng, 1980; Levin et al., 1987;

50
 Radiological Protection in Fluoroscopically Guided Procedures Performed Outside the Imaging Department

Giannoudis et al., 1998). Nowadays, nearly all orthopaedic disciplines have adopted
the use of fluoroscopy to meet their various needs. In the orthopaedic literature,
C-arm fluoroscopy has been reported for a wide variety of procedures including
anatomical localisation, bony reduction, implant placement, correction of malalign-
ment, arthrodesis, intra- and extramedullary bony fixation, joint injections, aspira-
tions, and a myriad of other common procedures. As indications for the use of
mobile C-arm fluoroscopy have expanded, its relative popularity has grown
commensurately. Through its relevance to numerous applications and overall conve-
nience, the use of fluoroscopy has become commonplace, and in some cases indis-
pensable, in the daily clinical practice of orthopaedics (Table 4.3).

Table 4.3. Indications for the use of mobile C-arm fluoroscopy in various orthopaedic procedures.
Orthopaedic applications Use of C-arm fluoroscopy
General Removal of some metallic items
Foreign/loose body removal
Trauma Anatomical localisation
Diagnostic (ipsilateral femoral neck/shaft fracture)
Fracture reduction (for casting/splinting or surgical fixation)
Intramedullary nailing
Kirshner wire/external fixator pin placement
Percutaneous hardware placement (i.e. cannulated/headless
screws, minimally invasive plate osteosynthesis plating, etc.)
Sports Guidance of joint entry for arthroscopy
Orientation and confirmation of acceptable implant placement
(i.e. distal biceps repair)
(i.e. anterior cruciate ligament (ACL), posterior cruciate
ligament (PCL), medical collateral ligament (MCL),
posterolateral corner / lateral collateral ligament (LCL)
reconstruction)
Assessment of depth and extent of bony resection
Spine Trauma
Level confirmation
Deformity correction
Hand/upper extremity Trauma
Assessment of adequate bony resection
Deformity correction
Anatomical localisation
Tumour Percutaneous biopsy
Cyst aspiration
Diagnostic (adjacent lesions)
Fracture reduction and implant placement
Radiofrequency ablation
Foot/ankle Trauma
Deformity correction
Assess adequacy of bony resection
Joint reconstruction Assessment of implant orientation/fixation
Assessment of limb alignment/joint line

51
 ICRP Publication 117

(99) Currently, the trend among many orthopaedic surgeons is to strive for min-
imal invasiveness when performing surgery. Through the collective initiative of med-
icine and industry, new technological advances have emerged, enabling orthopaedic
surgeons to execute procedures with much less soft tissue damage and resultant mor-
bidity for the patient. Unfortunately, operating in this manner creates a heightened
dependence on indirect visualisation to view pertinent anatomy. Thus, radiation
exposure of the patient and surgical team has increased commensurately with this
pursuit. Although some ascribe to the philosophy of ‘as low as reasonably achiev-
able’, this is not true for all, which is not desirable. Practitioners, more so in teaching
institutions, should be aware that their attitudes towards radiation safety get passed
on to trainees. A sense of responsibility towards patient and occupational radiolog-
ical protection is necessary.
(100) At present, arthrography, orthopaedics, and joint imaging procedures repre-
sent 8.4% of all fluoroscopy guided procedures in the USA, with an average effective
dose to the patient of 0.2 mSv/procedure, contributing 0.2% to the total collective
dose (NCRP, 2009). Similarly, in the UK, various imaging procedures in orthopae-
dics result in an effective dose of a few lSv to 1 mSv per procedure, contributing <1%
to the total collective dose to the population (Hart and Wall, 2002).

4.3.1. Levels of radiation dose

Dose to patient
(101) Patients receive radiation by direct exposure to the x-ray beam. This expo-
sure is much more intense than the scattered radiation that reaches workers. None-
theless, orthopaedic patients are at low risk for exhibiting tissue reactions, unlike
patients undergoing interventional vascular or cardiac procedures. Table 4.4 gives
typical fluoroscopy times and radiation doses to the patient during various orthopae-
dic procedures.
(102) For commonly performed procedures (intramedullary nailing of petrochan-
teric fractures, open reduction and internal fixation of malleolar fractures, and intra-
medullary nailing of diaphyseal fractures of the femur), mean fluoroscopy times of
3.2, 1.5, and 6.3 min, respectively, have been reported, while the estimated mean en-
trance skin doses were 183, 21, and 331 mGy, respectively (Tsalafoutas et al., 2008).
(103) The typical effective dose to patients with a femoral fracture treated surgi-
cally is 11.6–21.7 lSv (Perisinakis et al., 2004). The effective dose to patients for nail-
ing osteosynthesis of proximal pertrochanteric fractures has been shown to average
14 mSv, while the effective dose to patients for lower extremity fractures averaged
0.1 mSv (Suhm et al., 2001).
(104) Orthopaedic trauma surgeons are often responsible for stabilising pelvic
fractures. C-arm fluoroscopy is indispensible to the trauma surgeon for guiding bony
reduction and implant placement adjacent to major neurovascular structures. Given
the large cross-sectional diameter of the pelvis, fluoroscopic pelvic imaging has the
potential to lead to increased exposure of the patient and surgeon. Exposure data
have been collected during pelvic phantom imaging, and have demonstrated consid-
erable dose rate in the primary beam at the entrance surface (40 mGy/min)
52
 Table 4.4 Typical patient dose levels (rounded) from various orthopaedic procedures.

Radiological Protection in Fluoroscopically Guided Procedures Performed Outside the Imaging Department
Procedure Relative mean effective Relative mean Reported values Referenceà
dose to patient radiation dose
to patient*
0 mSv 35
Fluoroscopy Entrance skin Dose–area Effective
time (min) dose (mGy) product ðGycm2 Þ dose (mSv)
Skull A n.a. n.a. n.a. 0.1 a
Cervical spine A 0.2–0.8 n.a. 0.42–1.3 0.1–0.2 a,b
Thoracic spine A,B 0.85 n.a. 3.26 0.3–1.0 a,b
Lumbar spine A,B 0.10–1.4 n.a. 0.54–10 0.07–1.5 a,b
Pelvis A n.a. n.a. n.a. 0.6 a
Hip A 0.020–1.15 n.a. 0.64–2.6 0.10–0.74 a,b
Shoulder A n.a. n.a. n.a. 0.01 a
Knee A n.a. n.a. n.a. 0.005 a
Other extremities A n.a. n.a. n.a. 0.001 a
Hand/wrist B,C 0.20–0.55 0.08–1.1 0.04–0.22 <0.004 b,c
Distal radius plate osteosynthesis n.a. n.a. 1.8  17  n.a. n.a. d
Osteosynthesis of malleolar fracture n.a. n.a. 1.5  21  n.a. n.a. d
Plate osteosynthesis of tibial plateau n.a. n.a. 1.2  35  n.a. n.a. d
53

fracture
Arthroscopy for anterior cruciate n.a. n.a. 0.9  19  n.a. n.a. d
ligament (ACL) reconstruction
   
Tibial intramedullary nailing n.a. n.a. 5.7 137 n.a. n.a. d
Intramedullary nailing of n.a. n.a. 6.3  331  n.a. n.a. d
diaphyseal femoral fracture
Intramedullary nailing of n.a. n.a. 3.2  183  n.a. n.a. d
peritrochanteric fracture
   
Bilateral pedicle screw placement n.a. n.a. 0.8 46 n.a. n.a. d
in the lumbar spine
Bilateral pedicle screw placement n.a. n.a. 4.2  173  n.a. n.a. d
in the cervical spine
Vertebroplasty D,E 5–16 70–323 n.a. 8.5–13 d,e,f
Kyphoplasty C,D 10.1 320  (50–860) n.a. 4.3  (0.47–10) f,g
n.a., not available.
 
Mean value.
à
(a) Mettler et al., 2008; (b) Crawley and Rogers, 2000; (c) Giordano et al., 2007; (d) Tsalafoutas et al., 2008; (e) Miller et al., 2003a; (f) Seibert, 2004;
(g) Boszczyk et al., 2006.
* A, <1 mSv; B, 1–<2 mSv; C, 2–<5 mSv; D, 5–<10 mSv; E, 10–<20 mSv; F, 20–35 mSv; G, >35 mSv, based on effective dose.
 ICRP Publication 117

(Mehlman and DiPasquale, 1997). Other studies have found that during femoral or
tibial fracture nailing, the entrance skin dose to the patient is 183 mGy with a mean
fluoroscopy time of 3.2 min (Tsalafoutas et al., 2008). The same study examined pa-
tient exposure during pedicle screw placement in both the lumbar and cervical spine.
The surgical time for these cases averaged <1–7.7 min, which produced average en-
trance surface doses of 46 and 173 mGy for the lumbar spine and the cervical spine,
respectively. Associated ranges were 18–118 and 5–407 mGy, respectively (Tsalafou-
tas et al., 2008).
(105) Another study found that an average pedicle screw insertion procedure re-
quires 1.2 and 2.1 min of fluoroscopic exposure along antero-posterior and lateral
projections, respectively, resulting in DAPs of 2.32 and 5.68 Gycm2 , respectively.
Gender-specific normalised data for the determination of effective, gonadal, and en-
trance skin dose to patients undergoing fluoroscopically guided pedicle screw inter-
nal fixation procedures were derived. The effective dose from an average procedure
was 1.52 and 1.40 mSv, and the gonadal dose was 0.67 and 0.12 mGy for female and
male patients, respectively (Perisinakis et al., 2004). Minimally invasive spine proce-
dures require indirect visualisation to facilitate implant placement. Intuitively, this
would require longer procedural times with greater associated direct and scatter radi-
ation exposure. The mean dose to the patient’s skin is 60 mGy (range 8.3–252 mGy)
in the postero-anterior plane and 79 mGy (range 6.3–270 mGy) in the lateral plane
(Bindal et al., 2008). Overall, almost 90% of the collective dose from all orthopaedic
screening can be attributed to examination in five categories, namely dynamic hip
screw, cannulated hip screw, hip injection, lumbar spine fusion, and lumbar spine
discectomy. In fact, hips and spines account for 99% of total collective dose from
these common orthopaedic procedures, and therefore present as the obvious target
for dose reduction strategies (Crawley and Rogers, 2000).

Occupational dose levels

(106) A host of studies have established that orthopaedic surgeons who use C-arm
fluoroscopy are subject to occupational radiation exposure at levels that are typically
much lower than the dose limits recommended by the Commission. Reported doses
during various orthopaedic procedures usually fall well below international stan-
dards for annual occupational exposure limits (Jones et al., 2000; Singer, 2005;
Giordano et al., 2007, 2009a). However, there is a lack of real and reliable data
on radiation doses to workers, as many professionals do not use their personal
dosimeters regularly. Orthopaedic surgeons sustain the bulk of their exposure in
the form of scattered radiation, but also sometimes in the primary beam. Typical
scatter radiation dose levels arising from one of the most common orthopaedic pro-
cedures (intramedullary nailing of peritrochanteric fracture) for hands, chest, thy-
roid, eyes, gonads, and legs of the operating surgeon are, on average, 0.103, 0.023,
0.013, 0.012, 0.066, and 0.045 mGy/min, respectively (Tsalafoutas et al., 2008).
For 204 procedures, the corresponding cumulative doses would be 72, 16, 9.4, 8.3,
46, and 31 mGy. When protective aprons and collars are used, the actual effective
dose is only a small fraction (approximately 10%) of the personal dosimeter reading
(Tsalafoutas et al., 2008).

54
Radiological Protection in Fluoroscopically Guided Procedures Performed Outside the Imaging Department

(107) The reported radiation doses to the eyes and thyroid of the surgeon and sup-
porting staff from a mini C-arm unit during fluoroscopically guided orthopaedic an-
kle surgery range from 0.36 to 3.7 lGy/min, depending on the distance from the
patient (Mesbahi and Rouhani, 2008). The 10-fold decrease in scattered dose rate
corresponds with increased distance from 20 to 60 cm from the central beam axis.
For a typical 5-min procedure and a workload of 250 procedures/year, the un-
shielded equivalent dose to the lens of the eye would be <5 mSv when radiological
protection is employed.
(108) The use of intra-operative C-arm fluoroscopy in hand surgery is common
(Table 4.3). Both standard and mini C-arm units are used. Some data indicate that
exposure of the surgeon is higher than predicted during elective procedures involving
operative treatment of the fingers, hand, and wrist (Singer, 2005). The dose to the
hands of surgeons has been found to range from <10 to 320 lSv/case during mini
C-arm fluoroscopy (Singer, 2005; Giordano et al., 2007). Exposure of the surgeon
is believed to occur mainly as the result of direct exposure from beam contact during
extremity positioning, implant placement, and confirmation of acceptable bony
alignment. Radiation sustained from scattered exposure, on the other hand, has been
shown to be low. During hand surgery, depending on the position of the surgeon,
typical dose rates at chest level range from 4 to 20 lGy/h for a mini C-arm device;
when a standard C-arm device is used, the dose rate is typically 230 lGy/h. Corre-
sponding in-beam radiation doses are 37 and 65 mGy/h for mini- and standard C-
arm fluoroscopes, respectively (Athwal et al., 2005).
(109) Cadaveric specimens have been used to procure exposure data for patients
and surgeons during simulated foot/ankle procedures using both large and mini C-
arm fluoroscopes (Giordano et al., 2009b). Variable levels of dose to the patient
and surgeon have been found to depend on the location of the specimen within
the arc of the C-arm and the distance of the surgeon from the x-ray source. Surgeon
exposure has been shown to be universally low throughout all imaging configura-
tions during foot/ankle procedures (Gangopadhyay and Scammell, 2009; Giordano
et al., 2009b). An average rate of 2.4 lGy/min has been documented for mini C-arm
imaging of a foot/ankle specimen at a distance of 20 cm from the x-ray beam (Bad-
man et al., 2005). When the distance is increased, dose rates decrease according to
the inverse square law, as described in Section 3. For typical positions with respect
to a beam axis of 30 cm for the surgeon, 70 cm for the first assistant, and 90 cm for
the scrub nurse, the corresponding scatter dose rates at eye level are 0.1 mSv/min for
the surgeon, 0.06 mSv/min for the first assistant, and negligible for the nurse. This
indicates that individuals working P90 cm from the beam receive an extremely
low amount of radiation (Mehlman and DiPasquale, 1997).
(110) Procedures such as intramedullary nailing of tibial and femoral fractures re-
quire an average procedural time of 1–10 min, resulting in an average unprotected
dose rate to the surgeon of 0.128, 0.015, and 0.028 mSv/min for hands, eyes, and
chest, respectively. These values correspond to doses of 0.44, 0.05, and 0.10 mSv/case
(Sanders et al., 1993; Müller et al., 1998; Tsalafoutas et al., 2008). The average
unprotected thyroid dose rate during such procedures is 0.016 mSv/min or
0.06 mSv/case for a fluoroscopy time of 3.2 min/case (Tsalafoutas et al., 2008).
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 ICRP Publication 117

(111) During intramedullary nailing of femoral and tibial fractures, the equivalent
doses to the hands of the primary surgeon and the first assistant are 1.27 and
1.19 mSv, respectively, and the average fluoroscopy time is 4.6 min/procedure (Mül-
ler et al., 1998). For an average workload of 250 procedures/year, this would lead to
a dose to extremities of 300 mSv, which is significantly less than the dose limit of
500 mSv for extremities (Section 2).
(112) In a trauma setting, it is sometimes necessary for the surgeon to practice
‘damage control orthopaedics’. In this scenario, the severity of a patient’s injuries
and overall haemodynamic stability prevent execution of the definitive stabilisation
procedure. In this case, the patient would not tolerate a lengthy surgical time; there-
fore, external fixation of unstable musculoskeletal injuries is an appropriate tempo-
rising measure to achieve acceptable bony alignment and reduce haemorrhage.
Fluoroscopy is used to confirm adequate bony alignment and external fixator pin
placement. Exposure during external fixator placement has been measured, and it
has been found that the cumulative equivalent dose to the fingers of a surgeon for
a total of 44 procedures ranges from 48 to 2329 lSv. In 80% of procedures, the radi-
ation dose to the surgeon’s hand was <100 lSv (Goldstone et al., 1993). Nordeen
et al. (1993) reported monthly levels of radiation dose to orthopaedic surgeons in-
volved in the care of injured patients of 1.25 mSv total-body dose, 3.75 mSv eye
dose, and 12.5 mSv extremity dose. The dose to the hands was slightly higher at
3.95 mSv/month.
(113) Sports medicine specialists and surgeons practising arthroscopy do not usu-
ally need to use C-arm fluoroscopy as an adjunctive measure during surgery. Most
procedures are performed under direct visualisation using the arthroscope or
through open means. Nonetheless, some surgeons prefer to use C-arm fluoroscopy
during drilling of bony tunnels for ligament reconstruction and to confirm proper
implant positioning (Larson et al., 1995). In general, primary ligament reconstruc-
tions require less intra-operative fluoroscopy time, and primary allograft reconstruc-
tion seems to require the least amount of radiation if C-arm fluoroscopy is used. The
dose to the surgeon has been measured during such procedures and has been found
to be uniformly low at a dose rate of 0.7 lSv/min (Larson et al., 1995). For a typical
fluoroscopy time of 2.38 min, the average effective dose to the surgeon is 16 lSv/ pro-
cedure or 4 mSv/year for a workload of 250 procedures/year. Further studies using
other techniques and implants confirm low scatter radiation to the surgeon (Larson
and DeLange, 2008; Tsalafoutas et al., 2008).
(114) Orthopaedic surgeons who practice spinal surgery frequently use C-arm fluo-
roscopy to localise anatomical levels, assess bony alignment during deformity correc-
tion, and guide implant placement. As large body segments are imaged and these
areas fill the entire field of view of the image intensifier, the potential for amplified
radiation exposure of the patient and surgeon is high. Fluoroscopically assisted tho-
racolumbar pedicle screw placement exposes the spinal surgeon to significantly great-
er radiation levels (10–12 times) than other, non-spinal musculoskeletal procedures
that involve the use of a fluoroscope (Rampersaud et al., 2000). Radiation dose rates
to the surgeon’s neck and dominant hand are 0.08 and 0.58 mGy/min, respectively.
The dose rate to the torso was greater when the surgeon was positioned lateral to the
56
Radiological Protection in Fluoroscopically Guided Procedures Performed Outside the Imaging Department

beam source (0.53 mGy/min, compared with 0.022 mGy/min on the contralateral
side) (Rampersaud et al., 2000). Use of standard C-arm fluoroscopy during pedicle
screw fixation has been shown to expose the surgeon to an average dose rate of
0.58 mSv/min. This relatively high exposure requires strict adherence to radiological
protection measures.
(115) During minimally invasive transforaminal interbody lumbar fusion, for an
average fluoroscopy time of 1.7 min, the mean equivalent dose per case to the sur-
geon is 0.76 mSv on the dominant hand, 0.27 mSv at the waist under a lead apron,
and 0.32 mSv at unprotected thyroid level. Kyphoplasty and vertebroplasty, which
are minimally invasive spinal procedures, require both antero-posterior and lateral
real-time visualisation, often using biplane fluoroscopy equipment. In fact, 90% of
the orthopaedic surgeon’s effective dose and risk is attributed to kyphoplasty, while
another 8% is attributed to spinal procedures (Theocharopoulos et al., 2003). The
effective dose to the orthopaedic surgeon working tableside during a typical hip,
spine, and kyphoplasty procedure was 5.1, 21, and 250 lSv, respectively, when a
0.5-mm lead-equivalent apron alone was used. The additional use of a thyroid shield
reduced the effective dose to 2.4, 8.4, and 96 lSv per typical hip, spine, and kyphopl-
asty procedure, respectively.
(116) Procedures involving standard C-arm fluoroscopy of the cervical spine have
been shown to lead to a dose rate of 0.25–0.30 mSv/min to the surgeon’s hands,
which is somewhat lower than that for procedures involving the lumbar spine
(0.53–0.58 mSv/min) (Jones et al., 2000; Rampersaud et al., 2000; Giordano et al.,
2009a).

4.3.2. Radiation dose management

Patient dose management

(117) Diagnostic testing in orthopaedics relies heavily on imaging studies. Many of
these imaging modalities can be used interchangeably, with variable sensitivity for
soft tissue or bony anatomy. Meanwhile, procedures that rely on imaging for local-
isation, indirect visualisation, or instrument guidance often depend specifically on
ionising radiation as an imaging tool. For some minimally invasive orthopaedic pro-
cedures, C-arm fluoroscopy has supplanted direct visualisation and is requisite to
successful completion of the procedure. To help reduce intra-operative radiation
exposure, some authors have started to use alternative imaging modalities such as
ultrasound to perform procedures that previously relied more heavily on fluoroscopy
(Weiss et al., 2005; Hua et al., 2009; Mei-Dan et al., 2009). Although the use of such
modalities is relatively untested, they offer promising new alternatives to imaging
tools that use ionising radiation.
(118) Patient exposure has been shown to be reduced considerably (10 times) by
adhering to proper radiation safety practices and imaging the specimen closest to
the image intensifier. A significant learning curve is expected when using C-arm fluo-
roscopy during surgical procedures. Beam orientation, surgeon positioning, image
optimisation, and other logistical challenges require time for the surgeon to make

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 ICRP Publication 117

the most efficient use of the C-arm device. Screening times can be a useful tool to
measure optimum use of the C-arm fluoroscope during such surgical cases.
(119) Recent data suggest that although the mini C-arm device is capable of lim-
iting exposure dose to the patient and surgeon, care must still be taken during its use
(Giordano et al., 2007, 2008, 2009a,b). If the mini C-arm device is used in an injudi-
cious manner, the surgeon, patient, and surrounding staff may be subjected to con-
siderable scattered radiation exposure. Careless use of the mini C-arm device can
even exceed doses encountered when using the large C-arm device under equivalent
imaging conditions. Therefore, strict radiological protection measures, including the
routine use of protective lead garments, should be observed when using both
mini- and large C-arm fluoroscopes. The mini C-arm device should be used whenever
feasible in order to eliminate many of the concerns associated with use of the large
C-arm device, specifically those related to cumulative radiation hazards, positioning
considerations, relative distance from the beam, and the need for protective shielding
(Badman et al., 2005).
(120) Depending on the imaging configuration used, patient entrance skin dose
rate with the mini C-arm device can be approximately half that of the standard C-
arm device. The typical reported values are: 0.60 mGy/min (mini C-arm) and
1.1 mGy/min (large C-arm) for wrist surgery with cadaveric upper extremity (Athwal
et al., 2005) and immobilisation of wrist fractures. A frequent mistake in using the C-
arm device is to increase exposure parameters to improve image quality. However,
most imaging problems can be solved by adjusting brightness and contrast (Athwal
et al., 2005). Distance from the C-arm radiation source to the imaged object also
determines the amount of direct radiation exposure. Surgeons should make a con-
scious effort to image patients as far from the x-ray source as possible. With the mini
C-arm device, this would mean placing the imaged extremity directly on to the image
intensifier. With the standard C-arm device used in the recommended vertical posi-
tion, the source should be lowered to the floor to maximise the SSD (Athwal et al.,
2005).
(121) As the cross-sectional dimensions of the imaged body area or tissue density
of a patient increases, there is a precipitous amplification in exposure of both the pa-
tient and the surgical team. Thicker body portions remove more x rays than thinner
portions, and must be compensated for to provide consistent image information.
When the C-arm fluoroscope is set to the ‘normal’ mode, technique factors are ad-
justed automatically to produce an image of good clarity. Radiation production may
therefore increase significantly when imaging a larger body area. For orthopaedic
surgeons, this concept is pertinent because the amount of direct and scattered expo-
sure may vary considerably depending on the body area to be imaged. As the size of
the imaged extremity or tissue density increases, there is a notable augmentation of
direct exposure of the patient as well as indirect scatter exposure of the surgical team
(Giordano et al., 2007, 2008, 2009a,b; Yanch et al., 2009). This idea is particularly
relevant to orthopaedic surgeons who perform spinal surgery, as mentioned
previously.
(122) Even for orthopaedic surgeons who do not practice spinal surgery, the same
principles still apply and are critical to maintaining appropriate safety precautions.
58
Radiological Protection in Fluoroscopically Guided Procedures Performed Outside the Imaging Department

During fluoroscopic examination using a large C-arm device, radiation dose to the
patient has been shown to increase nearly 10-fold when imaging a foot/ankle speci-
men compared with a cervical spine. The dose to the surgical team, meanwhile, was
found to increase two- to three-fold (Giordano et al., 2007, 2008, 2009a,b). If a mini
C-arm fluoroscope was used for the same scenario, the dose to the patient increased
three- to four-fold, and the dose to the surgical team increased two-fold.
(123) Finally, all patient dose reduction actions described in Section 3 also apply
to orthopaedic surgery.

Occupational dose management

(124) X rays travel in straight lines and diverge in different directions as shown in
Fig. 3.7. The intensity decreases with distance according to the inverse square law. A
study in orthopaedic operating theatres showed that standing 90 cm from the x-ray
source vs 10 cm from the x-ray source decreased surgeon exposure from 0.20 mSv/case
to 0.03 mSv/case (Mehlman and DiPasquale, 1997). Traditionally, surgeons have been
taught that provided they stand at least 1.8 m from the x-ray source, they are at essen-
tially zero risk of being exposed to radiation (Tsalafoutas et al., 2008). This is not cor-
rect and has been called into question in studies which have demonstrated higher
exposure levels at a distance of 6 m from the x-ray source (Badman et al., 2005).
(125) Over the past several decades, mini C-arm fluoroscopy has emerged as a con-
venient imaging tool that has the potential to reduce radiation dose. Exposure levels
have been studied during various orthopaedic procedures and scenarios (Athwal
et al., 2005; Giordano et al., 2007, 2009b; Larson et al., 2008; Love et al., 2008).
Some operators may believe that provided they are outside the primary beam and
they do not see their body part in the image, their exposure is negligible. This is
based on the fact that most studies which give such advice have been conducted un-
der ideal circumstances, in contrast to more realistic applications that are encoun-
tered in practice. Exposure of the surgeon and operating team has been shown to
vary in relation to the orientation of the x-ray beam. In some cases, it is unavoidable
that the surgeon must stand in close proximity to the beam in order to maintain a
reduction or to secure implant placement. In those instances, the surgeon may be
at risk of exposure either by direct beam contact or through scatter radiation. Some
authors have demonstrated a dramatically reduced exposure dose when the surgeon
stood on the image intensifier side of the patient (Rampersaud et al., 2000). In effect,
placing the x-ray source under the operating table provides an effective beam stop in
some cases (Jones et al., 2000). When using the C-arm unit in a lateral or oblique
orientation, the surgeon should work on the image intensifier side of the table to re-
duce exposure from scattered radiation. While this may be true when imaging body
areas that intercept the beam fully, the same principle may not necessarily apply
when imaging a smaller body area where the beam may not be collimated to the
smaller size. In such a situation, some of the x-ray beam passes by the specimen unat-
tenuated, resulting in a higher dose on the opposite side. This must be taken into
consideration when positioning operating staff safely.
(126) Lead shielding is commonly used to attenuate exposure from scattered
radiation. Manufacturers cite variable protection depending on the thickness of

59
 ICRP Publication 117

the garment. In general, one can expect greater than 90% reduction in scatter expo-
sure from a lead gown of 0.5-mm lead thickness. Realistically, the ability of a lead
garment to attenuate scattered radiation is dependent upon the quality control ac-
tions taken to ensure that lead garments are well maintained. The protective benefit
afforded by lead can be compromised by poor maintenance. In a study of 41 lead
aprons, 73% were found to be outside the tolerance level of 5% for nominal lead-
equivalent values (Finnerty and Brennan, 2005). Furthermore, a recent report by
the American Academy of Orthopaedic Surgeons showed under-lead exposures to
be only 30–60% less than over-lead exposures (American Academy of Orthopaedic
Surgeons, 2008). This underscores the fallibility of this protective measure, as well
as the importance of proper maintenance and storage. Lead aprons should not be
folded but should be hung to improve their longevity. Imaging factors such as higher
tube voltages and imaging larger body areas can further decrease effectiveness. These
often-ignored variables should be clearly understood and corrected to improve pro-
tective measures.
(127) Use of a lead thyroid shield can reduce radiation exposure by a factor of 90%
or more depending upon the kV used and lead equivalence (see Section 3). The high-
est levels of exposure to the hands of the surgeon arise from inadvertent exposure to
the direct beam. Surgeons should ensure that they are positioned on the exit side of
the x-ray beam, rather than on the entrance side. The radiation intensity on the exit
side of the x-ray beam is typically around 1% (Section 3). Thus, every care should be
taken for staff to be on the exit side. Lack of awareness of this leads to unnecessary
exposure of staff. It is recognised that this may be unavoidable when maintaining a
difficult reduction, confirming adequate bony alignment, or securing implant place-
ment. In most cases, however, direct hand exposure is avoidable. When the ortho-
paedic surgeon’s or assistant’s hand is visible on a stored fluoroscopic image, it is
generally evidence of poor radiological protection practices (Fig. 4.1). In cases where
direct hand exposure is unavoidable, consideration may be given to using lead
gloves.
(128) Some of the first radiation exposure data recorded in the orthopaedic liter-
ature were collected during hip pinning and femoral nailing in the traumatised pa-
tient (Giachino and Cheng, 1980; Giannoudis et al., 1998). As described in
Section 3, increased distance from the patient is an efficient tool for dose reduction.
For a lateral projection and laterally directed x-ray beam (surgeon stands beside im-
age receptor), the dose rate decreased from 1.9 to 0.2 mGy/h when distance was in-
creased from 2.5 to 45 cm. Similarly, for a lateral projection and x-ray beam directed
towards the midline (surgeon stands beside x-ray tube), the dose rate decreased from
77 to 1.5 mGy/h when distance was increased from 2.5 to 45 cm (Giachino and
Cheng, 1980).

4.4. Obstetrics and gynaecology

(129) Most radiological examinations in obstetrics and gynaecology are performed

within radiology, but there are situations where they are performed in gynaecology
practice and thus are included in this report.
60
 Radiological Protection in Fluoroscopically Guided Procedures Performed Outside the Imaging Department

Fig. 4.1. Fluoroscopic image obtained to demonstrate satisfactory internal fixation of a fracture of the
distal humerus. The assistant is holding the forearm, and three of the assistant’s fingers are included in the
image. This is poor practice. Source: D. Miller.

(130) Obstetrics and gynaecological studies in the USA account for 4.5% of all
fluoroscopically guided diagnostic and interventional procedures, with a mean effec-
tive dose of 1 mSv. This contributes <1% to the total collective dose (NCRP, 2009).
(131) Hysterosalpingography is a relatively common radiological procedure that is
used to assess the uterine cavity and the patency of the Fallopian tubes. The common
indication for hysterosalpingography is primary and secondary infertility. It should
not be forgotten that pregnancy can occur in these patients, and pregnancy tests
should be performed unless there is information that precludes a pregnancy.
(132) Pelvimetry is an old procedure that was performed for assessment of mater-
nal pelvic dimensions. This procedure may still be in use in some countries. Pelvim-
etry is usually considered necessary where vaginal delivery is contemplated in a
breech presentation, or if reduced pelvic dimensions are suspected in a current or
previous pregnancy.
(133) Historically, in a number of countries, pelvimetry represented the major sin-
gle source of ionising radiation to the fetus. While radiographic pelvimetry is some-
times of value, it should only be undertaken on the rare occasions when this is likely
to be the case, and should not be carried out on a routine basis. X-ray pelvimetry
only provides limited additional information to physicians involved in the manage-
ment of labour and delivery. In the few instances in which the clinician thinks that
pelvimetry may contribute to a medical treatment decision, the reasons should be
clearly delineated (ICRP, 2000).
(134) Conventional pelvimetry includes radiography, but digital fluorography,
CT, magnetic resonance imaging (MRI), and ultrasound are currently used for pel-
vimetry (Thomas et al., 1998; ICRP, 2000).

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 ICRP Publication 117

(135) Uterine artery embolisation is a minimally invasive procedure for therapy

for uterine fibroids (leiomyomata). It can be accepted as an alternative to surgery
in general practice; however, radiation effects from this procedure should be assessed
carefully, as it is associated with relatively long fluoroscopy times and a large number
of images (Nikolic et al., 2000).

4.4.1. Levels of radiation dose

Dose to patient
(136) The radiation dose to mother and fetus in pelvimetry can vary by a factor of
20–40 depending upon the techniques used, namely CT, conventional radiography,
or digital fluorography (Table 4.5).
(137) CT pelvimetry with a lateral scanogram generally gives the lowest
radiation dose, and conventional radiography using an air gap technique with
a single lateral view is a relatively low-dose alternative where CT is not avail-
able (Thomas et al., 1998). In comparison, the reported effective dose from
conventional pelvimetry is in the range of 0.5–5.1 mSv, which is significantly
higher than the effective dose of 0.2 mSv from CT pelvimetry (Hart and Wall,
2002).
(138) A typical effective dose to a patient undergoing hysterosalpingography as
part of their infertility work-up is 1.2–3.1 mSv (Table 4.5), with ovarian doses in
the range of 2.7–9.0 mGy. However, higher effective doses of 8 mSv and ovarian
doses of 9–11 mGy have been reported (Fernández et al., 1996; Nakamura et al.,
1996; Gregan et al., 1998). The effective dose from uterine artery embolisation can
be even higher, ranging from 15 to 26 mSv, with relatively high skin and ovarian
doses (Nikolic et al., 2000; Glomset et al., 2006). Reported estimated mean uterine
and ovarian doses are 81–101 mGy and 85–105 mGy, respectively (Glomset et al.,
2006).

Occupational dose levels

(139) During hysterosalpingography, if the examination protocol involves fluoro-
scopic guidance, workers will need to be located inside the x-ray room. When the
procedure involves radiography alone, workers will be located outside the room at
the console. A protective lead apron should be worn by workers when inside the
x-ray room, and other protective measures mentioned in Section 3 should also be
adopted.
(140) There are few publications on this subject. One recent paper reported an en-
trance surface dose value of 0.18 mGy/procedure, with a slight increase when hyster-
osalpingography is performed on conventional x-ray film compared with digital
(0.21 mGy vs 0.14 mGy). Doses to the lens of the eye, thyroid, and hands of workers
are reported to be 0.22, 0.15, and 0.19 mGy/procedure, respectively. The risk for
workers is negligible when a lead apron of 0.35–0.5 mm lead equivalence is worn
(Sulieman et al., 2008).

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 Radiological Protection in Fluoroscopically Guided Procedures Performed Outside the Imaging Department
Table 4.5. Typical patient dose levels from gynaecological procedures (rounded) and comparison with computed tomography.
Procedure Relative mean radiation Relative mean Reported values Reference 
effective dose to patient radiation dose
to patient*
0 mSv 35
Fluoroscopy Entrance skin Dose–area Effective
time (min) dose (mGy) product dose (mSv)
ðGycm2 Þ
Pelvimetry, conventional A n.a. 4.2–5.1 1.4 0.4–0.8 a,b,c
63

Pelvimetry, digital fluorography A 0.3 3.6 0.10–0.46 0.43 d

Computed tomography pelvimetry A n.a. n.a. n.a. 0.2 c
Hysterosalpingography B,C 0.3–14 9.7–30 4–7 1.2–3.1 b,c,e,f,g,h,i,j
Uterine artery embolisation E,F 21–36 453–1623 53–89 22–32 l,m
n.a., not available.
 
(a) Russel et al., 1980; (b) NCRP, 2009; (c) Hart and Wall, 2002; (d) Wright et al., 1995; (e) Sulieman et al., 2008; (f) Gregan et al., 1998; (g) Perisinakis
et al., 2003; (h) Fife et al., 1994; (i) Fernández et al., 1996; (j) Calcchia et al., 1998; (l) Nikolic et al., 2000; (m) Glomset et al., 2006.
* A, <1 mSv; B, 1–<2 mSv; C, 2–<5 mSv; D, 5–<10 mSv; E, 10–<20; F, 20–35 mSv; G, >35 mSv, based on effective dose.
 ICRP Publication 117

4.4.2. Radiation dose management

Patient dose management

(141) Section 3 deals with patient dose management in great detail.
(142) In hysterosalpingography, a standard procedure may involve around 0.3 min
of fluoroscopy and three to four images (Perisinakis et al., 2003). Prolonged fluoros-
copy time and a higher number of acquired images will increase the patient dose.
Hysterosalpingography is typically performed in antero-posterior and oblique pro-
jections. For a total effective dose in hysterosalpingography of 2 mSv, the contribu-
tions from antero-posterior and oblique projections are typically 1.3 and 0.7 mSv,
respectively (Calcchia et al., 1998).
(143) Increasing the tube voltage is an efficient method for dose reduction in hys-
terosalpingography, as ovarian dose is decreased by approximately 50% when tube
voltage is increased from 70 to 120 kV (Kramer et al., 2006). Choice of posterior–
anterior projection and increased filtration are other possible steps to reduce the dose
to patients. As an example, the use of additional filtration could lead to dose reduc-
tion of >80% without loss of image quality in hysterosalpingography in computed
radiography systems (Nagashima et al., 2001).
(144) There is evidence of almost six-fold dose reduction as a result of transition
from screen-film to digital imaging equipment. In a comparative dosimetric study of
hysterosalpingography performed on conventional screen-film undercouch x-ray
units and digital C-arm radiological fluoroscopy units, entrance surface doses of
15 and 2.5 mGy were found for screen-film and digital units, respectively (Gregan
et al., 1998). The corresponding ovarian doses were 3.5 and 0.5 mGy (Gregan
et al., 1998). As almost 75% of the total dose in hysterosalpingography is due to radi-
ography and only 25% is due to fluoroscopy (Fernández et al., 1996), a significant
dose reduction could be achieved by using stored digital images without further pa-
tient exposure. The use of C-arm fluoroscopic imaging systems with pulsed fluoros-
copy and last-image-hold capability is desirable (Phillips et al., 2010).
(145) The fundamental approach in dose reduction in hysterosalpingography is to
reduce fluoroscopy time and the number of images taken.

Occupational dose management

(146) It has been demonstrated that mean screening time is highly operator depen-
dant. The observed screening time for procedures performed by gynaecologists or
trainee doctors is higher compared with that for radiologists (Sulieman et al.,
2008). Therefore, hysterosalpingography should be performed by experienced physi-
cians with training and skill in radiological protection and radiation management. In
general, all patient dose reduction methods can also reduce the dose to physicians
and support personnel involved in the examination. Furthermore, the use of an over-
couch x-ray unit increases scatter dose to the face, neck, and upper parts of the oper-
ator’s body.
(147) The occupational dose management actions described in Section 3 are also
generally applicable in gynaecological procedures.

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Radiological Protection in Fluoroscopically Guided Procedures Performed Outside the Imaging Department

4.5. Gastroenterology and hepatobiliary system

(148) The use of ionising radiation in gastroenterology and hepatobiliary proce-

dures is somewhat in transition. In the past, gastroenterologists performed a variety
of interventions involving radiation exposure, including gastrointestinal and hepa-
tobiliary x-ray studies, placement of small bowel biopsy tubes, oesophageal dilation,
and assistance with colonoscopy, as well as diagnostic and therapeutic procedures on
the pancreaticobiliary system during ERCP. ERCP and other biliary procedures re-
quire fluoroscopic guidance, and most of the current x-ray exposure is from ERCP,
luminal stents, and dilation. The other procedures are becoming supplanted by
improvements in diagnostic equipment and techniques. Gastroenterologists who
are involved in ERCP procedures may work at specialised centres and may perform
multiple procedures daily. In many circumstances where fluoroscopic and/or X-ray
equipment are used, gastroenterologists have the opportunity to minimise risk to pa-
tients, staff, and themselves.
(149) ERCP studies account for 8.5% of all fluoroscopically guided diagnostic and
interventional procedures in the USA, with a mean effective dose of 4 mSv. They
contribute 4–5% to the total collective dose from fluoroscopically guided interven-
tions (NCRP, 2009).
(150) During ERCP, fluoroscopy is used to verify the position of the endoscope
and its relationship within the duodenum. The placement of catheters and guide
wires is also verified fluoroscopically. Once contrast injections are performed, fluo-
roscopy is used to evaluate the anatomy of the ductal systems of both the biliary
tree and the pancreas, and to help define potential diseases present. Images are
usually taken to record the findings, either by capturing the last fluoroscopic image
or spot radiographs. Finally, the use of fluoroscopy to assist therapy, such as
sphincterotomy, stone extraction, biopsy or cytology, and stent placement is re-
quired. Additional devices that allow direct visualisation of ductal anatomy may
ultimately reduce the need for fluoroscopy (World Gastroenterology Organisation,
2009).

4.5.1. Levels of radiation dose

Dose to patient
(151) Typical patient dose levels for common gastroenterology and hepatobiliary
procedures involving x rays are presented in Table 4.6. Single and double contrast
barium enemas are x-ray examinations of the large intestine (colon and rectum).
Barium swallow is an x-ray examination of the upper gastrointestinal tract. These
traditional x-ray examinations in gastroenterology are associated with effective
doses ranging from 1–3 mSv (barium swallow and barium meal) to 7–8 mSv (small
bowel enema and barium enema) (UNSCEAR, 2010). Although these studies are
mainly performed within imaging departments, it is important that gastroenterol-
ogists are aware of typical dose levels and risks. At present, many barium studies
have been replaced by endoscopic procedures that exclude the use of ionising
radiation.
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 Table 4.6. Typical patient dose levels (rounded) from gastroenterology and hepatobiliary procedures.
Procedure Relative mean effective Relative mean Reported values Reference 
dose to patient radiation dose
to patient*
0 mSv 35
Fluoroscopy Entrance skin Dose–area Effective
time (min) dose (mGy) product ðGycm2 Þ dose (mSv)

ICRP Publication 117

ERCP (diagnostic) C,D 2–3 55–85 15 3–6 a,b
ERCP (therapeutic) E,F 5–10 179–347 66 20 a,b
Biopsy C n.a. n.a. 6 1.6 a,c
66

Bile duct stenting E n.a. 499 43–54 11–14 a,c,d

Percutaneous transhepatic D 6–14 210–257 31 8.1 a
cholangiography
Bile duct drainage F,G 12–26 660 38–150 10–38 a,d,e
Transjugular intrahepatic F,G 15–93 104–7160 14–1364 19–87 a,e,f
portosystemic shunt creation
Transjugular hepatic biopsy D 6.8 n.a. 34 5.5 f
ERCP, endoscopic retrograde cholangio-pancreatography; n.n., not available.
 
(a) UNSCEAR, 2010; (b) Olgar et al., 2009; (c) Hart et al., 2002; (d) Dauer et al., 2009; (e) Miller et al., 2003a; (f) McParland, 1998.
* A, <1 mSv; B, 1–<2 mSv; C, 2–<5 mSv; D, 5–<10 mSv; E, 10–<20; F, 20–35 mSv; G, >35 mSv, based on effective dose.
Radiological Protection in Fluoroscopically Guided Procedures Performed Outside the Imaging Department

(152) For the patient, the source of exposure is the direct x-ray beam from the x-
ray tube. It is estimated that patients receive approximately 2–16 min of fluoroscopy
during ERCP, with therapeutic procedures taking significantly longer. Studies have
found that DAP values of approximately 13–66 Gycm2 are typical for ERCP. Effec-
tive doses ranging from 2 to 6 mSv/procedure have been reported (World Gastroen-
terology Organisation, 2009).
(153) Care of the patient undergoing an endoscopic procedure continues to be-
come more complex as technology advances. Due to higher complexity, doses from
therapeutic ERCP are typically higher than doses from diagnostic ERCP. For diag-
nostic ERCP, the average DAP is 14–26 Gycm2 , while it reaches 67–89 Gycm2 for
therapeutic ERCP. Corresponding entrance skin doses are 90 and 250 mGy for
diagnostic and therapeutic ERCP, respectively. The mean effective doses are 3–
6 mSv for diagnostic ERCP and 12–20 mSv for therapeutic ERCP (Larkin et al.,
2001; Olgar et al., 2009). Fluoroscopic exposure accounts for almost 70% of the
dose for diagnostic ERCP, and >90% of the dose for therapeutic ERCP, indicating
that reduction of fluoroscopy time is an efficient method for dose management (Lar-
kin et al., 2001).
(154) The estimated radiation dose and associated risks for fluoroscopically
guided percutaneous transhepatic biliary drainage and stent implantation proce-
dures indicate that radiation-induced risk may be considerable for young patients
undergoing these procedures. The average effective dose varies from 2 to 6 mSv
depending on procedure approach (left vs right access) and procedure scheme.
However, effective dose may be higher than 30 mSv for prolonged fluoroscopy
times (Stratakis et al., 2006; UNSCEAR, 2010). In the available literature, the re-
ported DAP values for biliary drainage are in the range of 38–150 Gycm2 , which,
based on an appropriate conversion factor from DAP to effective dose, corre-
sponds to an effective dose of 10–38 mSv/procedure (Miller et al., 2003a; Dauer
et al., 2009; UNSCEAR, 2010).

Occupational dose
(155) For gastroenterologists and other staff, the major source of x-ray exposure
is scattered radiation from the patient, rather than the primary x-ray beam. Aver-
age effective doses of approximately 2–70 lSv/procedure have been observed for
endoscopists wearing lead aprons (Olgar et al., 2009; World Gastroenterology
Organisation, 2009). Although the endoscopist’s body is well protected by a lead
apron, there can also be substantial doses to unshielded parts. For a single ERCP
procedure, typical doses of 94–340 lGy to the head and neck region (eyes and thy-
roid) and 280–830 lGy to the fingers have been reported (Buls et al., 2002; Olgar
et al., 2009). For PTC (percutaneous transhepatic cholangiography), reported
doses are in the range of 300–360 lGy/procedure for the head and neck and
530–1000 lGy/procedure for the fingers (Olgar et al., 2009). For a workload of
three to four procedures/week, Naidu et al. (2005) reported extrapolated annual
doses to the thyroid gland and extremities for operators performing ERCP studies
of 40 and 7.92 mSv, respectively. Doses to assisting personnel are usually lower,

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 ICRP Publication 117

depending on position and the time spent near the x-ray source, as they usually
stand further away from the patient (World Gastroenterology Organisation, 2009).
(156) Jorgensen et al. (2010) reported the typical annual workload for the ERCP
providers, stating that 34% of them perform <100 ERCP procedures/year, 38% per-
form 100–200 procedures/year, and 28% perform >200 procedures/year.
(157) It is not possible to document the health effects of ionising radiation at the
dose levels to which gastroenterologists performing ERCP or fluoroscopy are ex-
posed; annual effective doses are typically 0–3 mSv when appropriate radiological
protection tools and principles are applied (World Gastroenterology Organisation,
2009). Nevertheless, many gastroenterologists involved in diagnostic and therapeutic
procedures using ionising radiation do not routinely wear full protective clothing
(protective aprons, thyroid shield, lead glasses). Audits of radiation exposure of per-
sonnel performing ERCP found that workers can be exposed to significant radiation
exposure, as only half of the respondents reported regular use of a thyroid shield
(Frenz and Mee, 2005).
(158) Typical equivalent doses for hands, neck, forehead, and gonads during per-
cutaneous procedures under fluoroscopic guidance, such as percutaneous cholangi-
ography and transhepatic biliary drainage, are: 13–220 lSv for hands, 0.007–
0.027 lSv for thyroid and lens of the eye, and negligible for gonads under a lead
apron. The assessed annual dose levels fall below regulatory dose limits for occupa-
tional exposure (Benea et al., 1988).
(159) While it is well known that an overcouch tube x-ray unit is not adequate
for performing interventional procedures, ERCP commonly involves the use of this
type of equipment. Olgar et al. (2009) reported typical doses of 94 and 75 lGy for
the eye and neck, respectively, of a gastroenterologist. With an overcouch unit,
typical eye and neck doses are 550 and 450 lGy, with maximal doses up to 2.8
and 2.4 mGy/procedure, respectively (Buls et al., 2002). Dose to the lens of the
eye is critical, as for a moderate workload, the annual equivalent dose limit for
the lens of the eye of 20 mSv could be reached. This is clearly dependent on the
type of x-ray equipment used.

4.5.2. Radiation dose management

Patient dose management

(160) Where possible, ERCP should be reserved for situations where interven-
tion is likely, using alternative modalities for purely diagnostic purposes (e.g.
magnetic resonance cholangio-pancreatography) (Williams et al., 2008). Reported
occupational dose levels using overcoach tube units may indicate that ERCP pro-
cedures are often performed without attention to equipment and radiological pro-
tection. There is evidence that a correctly operated C-arm unit with the
availability of pulsed fluoroscopy will dramatically reduce the dose to both pa-
tients and workers (Buls et al., 2002). In addition, use of a grid-controlled pulsed
fluoroscopy unit could achieve significantly lower patient doses without loss in
diagnostic accuracy compared with a conventional continuous fluoroscopy unit

68
Radiological Protection in Fluoroscopically Guided Procedures Performed Outside the Imaging Department

for a variety of abdominal and pelvic fluoroscopic examinations (Boland et al.,

2000).
(161) In any procedure when fluoroscopy is used for guidance, the shortest possi-
ble period of fluoroscopy is recommended. Therefore, both patient and occupational
doses could be reduced by time-limited fluoroscopy that significantly decreases fluo-
roscopy time and dose (Uradomo et al., 2007).
(162) Best practice during ERCP includes positioning of the x-ray tube below the
table as far away as possible, positioning oneself as far away as possible from the
X-ray tube and patient, and, wearing a protective apron, thyroid shield, and leaded
eyewear. Maintaining x-ray equipment in optimum operating condition, using
pulsed fluoroscopy, minimising fluoroscopy time, limiting the number of radio-
graphic images, using shielding barriers, collimation, and reduced use of magnifi-
cation will help to reduce x-ray exposure of the workers as well as that of the
patient. Anything that increases the amount of radiation exposure (e.g. longer fluo-
roscopy time, generation of more radiographic images, proximity to the radiation
source, positioning the X-ray source above the patient, and proximity of the work-
er to the patient) will increase the radiation dose and potential risk from ionising
radiation.
(163) The patient dose management actions described in Section 3 are generally
applicable in gastroenterology and hepatobiliary procedures.

Occupational dose management

(164) Patient and occupational exposure are related. Any action to reduce patient
dose will also reduce the dose to workers.
(165) It is obvious that ERCP and TIPS (transjugular intrahepatic portosystemat-
ic shunt) have the potential to cause high occupational doses, and consequently re-
quire attention regarding radiological protection. The reported dose levels indicate
that ERCP and TIPS require the same radiological protection practices as all inter-
ventional procedures. The Commission covered radiological protection issues in
interventional procedures in Publication 85 (ICRP, 2001).
(166) Specific written policies and procedures for the safe use of radiographic
equipment must be available to all gastroenterology personnel. Endoscopy personnel
can limit occupational exposure to radiation by using the principles based on dis-
tance, time, and shielding, as described in Section 3 of this report. For example, a
well-positioned, 0.5-mm lead-equivalent acrylic shield will reduce occupational expo-
sure by a factor of 11 (Chen et al., 1996). Besides basic dose management actions, if a
single-sided apron is being used, it is important to face the radiation-emitting unit at
all times. If this is not possible and duties require staff members to turn away from
the radiation source, exposing their backs, a wrap-around apron that provides pro-
tection around the body must be used (SGNA, 2008).
(167) As outlined in Section 3, training and experience are powerful dose reduction
tools. The fluoroscopy time is shorter when ERCP is performed by endoscopists with
more years of experience of performing ERCP and who performed a greater number
of ERCPs in the preceding year. Endoscopists who performed <100 and 100–200
ERCP procedures in the preceding year had 59% and 11% increases in fluoroscopy

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 ICRP Publication 117

time, respectively, compared with endoscopists who performed >200 ERCP proce-
dures in the preceding year. Every 10 years of experience was associated with a
20% decrease in fluoroscopy time (Jorgensen et al., 2010).

4.6. Anaesthetics and pain management

(168) Local spinal pain and radiculopathy are very common conditions. As
imaging abnormalities do not correlate with symptoms in most cases, many pa-
tients do not receive a specific diagnosis and have continued pain. Percutaneous
injection techniques have been used to treat back pain for many years, and have
been controversial. Many of these procedures have historically been performed
without imaging guidance. Imaging-guided techniques with fluoroscopy or CT in-
crease the precision of these procedures and help to confirm needle placement. As
imaging-guided techniques should lead to better results and reduced complication
rates, they are becoming more popular (Silbergleit et al., 2001). Epidural injections
are commonly used for the treatment of lower back pain in patients for whom con-
servative disease management has failed and who may wish to avoid, or cannot
have, surgery (Wagner, 2004).
(169) Reported patient doses during fluoroscopy guided epidural injections are
higher when continuous fluoroscopy is used. When pulsed fluoroscopy is used, the
patient effective dose per minute of fluoroscopy is significantly lower: 0.08, 0.11,
and 0.18 mSv for 3, 7.5, and 15 pulses/s, respectively (Schmid et al., 2005). During
CT fluoroscopic guidance, typical effective patient doses are in the range of 1.5–
3.5 mSv for a standard protocol and 0.22–0.43 mSv for a low-dose protocol, depend-
ing on the number of consecutive scans performed. Therefore, an 80–90% reduction
in effective dose has been reported by applying pulsed fluoroscopy, while the use of a
low-dose CT protocol in terms of reduced mA and tube rotation time reduces the
effective dose by >85% (Schmid et al., 2005).
(170) The reported radiation dose to the operator during CT fluoroscopy guided
lumbar nerve root blocks outside the lead protection is typically 1–8 lSv/procedure
(Wagner, 2004).
(171) The factors that greatly influence the dose to the operator are: equipment
technology, use of shielding, operator’s experience, use of lower mA, and smaller
scan volume. The patient dose has also been greatly reduced by these techniques,
and by using pulsed fluoroscopy and reduced mA values during CT fluoroscopic
guidance (Wagner, 2004; Schmid et al., 2005).

4.7. Sentinel lymph node biopsy

(172) The sentinel lymph node (SLN) is the first lymph node to which cancer is
likely to spread from the primary tumour. Cancer cells may appear in the SLN be-
fore spreading to other lymph nodes. A SLNB is based on the premise that cancer
cells spread (metastasise) in an orderly way from the primary tumour to the SLN,
and then to other nearby lymph nodes. A negative SLNB result suggests that cancer
has not spread to the lymph nodes. A positive result indicates that cancer is present
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Radiological Protection in Fluoroscopically Guided Procedures Performed Outside the Imaging Department

in the SLN and may be present in other lymph nodes in the same area (regional
lymph nodes).
(173) Several reports have demonstrated accurate prediction of nodal metastasis
with radiolocalisation and selective resection of the radiolocalised SLN in patients
with cancer of the breast, vulva, penis, head and neck, and melanoma. The list is
expanding with ongoing research. Accurate identification of the SLN is paramount
for the success of this procedure. SLNB is the evolving standard of care for the man-
agement of early breast cancer. In SLNB, only the first node draining a tumour is
removed for analysis. Clearance to achieve local control is reserved for those with
a positive SLNB.
(174) Various techniques are described for SLN identification, but injection of
a radiotracer into the tumour is most common. Pre-operative lymphoscintigra-
phy provides a road map for the surgeon and requires a reporting template.
99m
Technetium (Tc) sulphur colloid has been used for over a decade and offers
the potential for improved staging of breast cancer with decreased morbidity. In-
tra-operative gamma-ray detection is used to identify and remove the ‘hot’
node(s).
(175) The use of radioactive materials in the operating theatre generates significant
concern about radiation exposure. As reliance on this technique grows, its use by
those without experience in radiation safety will increase.

4.7.1. Levels of radiation dose

Dose to patient
(176) 99mTc sulphur colloid or nano colloid is a commonly used radiotracer,
and there has been an inclination to find positron-emitting radiopharmaceuticals
in recent years. 99mTc is a pure gamma emitter. When injected as a colloid, it re-
mains localised, and the radiation dose to the patient is extremely small with the
activity used for this procedure. As a result, there is a lack of published reports
on radiation doses to patients in SLNB procedures, and most papers address the
issue of occupational exposure. One needs to address the concern of radiation
dose to the pregnant patient and fetus. Estimated fetal dose is normally
<0.1 mGy (typically  0.01 mGy), and effective dose to the patient is generally
<0.5 mSv using 18.5 MBq of 99mTc colloid. These doses are too small to preclude
the use of this technique in pregnancy when there is clinical benefit and alterna-
tive techniques cannot provide the same information. The fact that due consider-
ations have taken place should be recorded (Pandit-Taskar et al., 2006;
Spanheimer et al., 2009).

Occupational dose levels

(177) Physicians administering the radiotracer injection in SLNB receive equiva-
lent doses to the hands of 2.3–48 lSv/case, with a maximal dose up to 164 lSv.
Surgeons receive equivalent doses to the hands of 2–8 lSv/case (Nejc et al., 2006).
However, there are studies indicating that the equivalent dose to the hands of
operating surgeons can be as high as 22–153 lSv, depending on the technique

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 ICRP Publication 117

applied (De Kanter et al., 2003). Notably, other members of the medical team receive
similar doses (4.3–7.9 lSv/case) (Nejc et al., 2006). Several other studies have re-
ported similar minimal occupational radiation doses with SLNB (Miner et al.,
1999; Waddington et al., 2000; Klausen et al., 2005). Considering a typical workload
in a moderate hospital of approximately 20 patients/year, the annual equivalent dose
to the hands using these figures can be up to 3 mSv, whereas the Commission’s dose
limit is 500 mSv.

4.7.2. Radiation dose management

Patient dose management

(178) Use of the principle of optimisation of radiological protection promotes
administration of the lowest amount of radioactivity required to obtain the desired
clinical information. Furthermore, the use of alternative techniques using non-ionis-
ing radiation is preferred when similar information can be obtained, particularly in
pregnancy.

Occupational dose and radioactive waste management

(179) There are indications that the radiation dose to the hands of medical staff is
smaller when SLNB is performed as a 2-day procedure, where surgery is performed
24 h after the injection of radiotracer. Four physical half-lives of the radiotracer pass
over 24 h (99mTc, t1=2 =6.02 h). Moreover, the activity is further diminished due to
clearance of the radiotracer from the blood (Waddington et al., 2000; Nejc et al.,
2006).
(180) Radioactive waste is created in the operating theatre, and may be generated
in the pathology laboratory if specimens are not routinely stored until fully decayed.
(181) A general framework for radiological protection and disposal of radioactive
waste was published by the Commission in Publication 77 (ICRP, 1997). It should be
remembered that the primary aim of radiological protection is to provide an appro-
priate standard of protection for humans without unduly limiting the beneficial prac-
tices giving rise to radiation exposure. For the control of public exposure from waste
disposal, the Commission retained the Publication 77 value for the dose constraint
for members of the public (no more than approximately 0.3 mSv/year) in its 2007
Recommendations (ICRP, 2007b). Special considerations for radioactive waste
materials are not required, but it is suggested that such waste materials should be
sealed and stored for decay before disposal at the designated place in accordance
with local rules.
(182) Radioactivity contamination in operating room materials is also minimal
and requires normal precautions in handling. Letting radioactivity decay with time
by storing the specimens for a few hours is a sufficient precaution for pathologists
handling the SLNB specimens. Following the safety guidelines, the specimens aris-
ing from SLNB procedures should be stored for decontamination until the dose
rate falls to background levels (Stratmann et al., 1999). Depending upon the
administered activity, this takes approximately 60–70 h for primary specimens
and 30–40 h for nodes following 99mTc sulphur colloid injection (Miner et al.,

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 Radiological Protection in Fluoroscopically Guided Procedures Performed Outside the Imaging Department

1999; Filippakis and Zografos, 2007). A local risk assessment should be carried out
prior to undertaking these procedures. Transport and disposal of decayed radioac-
tive waste should be performed in accordance with national regulatory
requirements.

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 Radiological Protection in Fluoroscopically Guided Procedures Performed Outside the Imaging Department

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 5. PREGNANCY AND CHILDREN

 Medical radiation applications on pregnant patients should be justified and tailored

to reduce fetal dose.
 Termination of pregnancy at fetal doses of <100 mGy is not justified based upon
radiation risk.
 The restriction of a dose of 1 mSv to the embryo/fetus of pregnant worker after dec-
laration of pregnancy does not mean that it is necessary for a pregnant woman to
avoid work with radiation completely, or that she must be prevented from entering
or working in designated radiation areas.
 Pregnant medical workers may work in a radiation environment provided that there
is reasonable assurance that the fetal dose can be kept below 1 mSv during the course
of pregnancy. It does, however, imply that the employer should review the exposure
conditions of pregnant women carefully.

5.1. Patient exposure and pregnancy

(183) Medical exposure of a pregnant female presents a unique challenge to pro-

fessionals because of the concern about the radiation risk to the fetus compared with
the risk of not carrying out the procedure. Thousands of pregnant patients and
workers are exposed to ionising radiation each year. Lack of knowledge is responsi-
ble for great anxiety and probably unnecessary termination of pregnancies (ICRP,
2000). This section is focused on situations of known pregnancy, as well as exposure
in situations of unknown or undeclared pregnancy. The Commission covered this to-
pic extensively in Publication 84 (ICRP, 2000).
(184) The potential biological effects of in-utero radiation exposure of a devel-
oping fetus include prenatal death, intra-uterine growth restriction, small head
size, mental retardation, organ malformation, and childhood cancer. The risk
of each effect depends on gestational age at the time of exposure, fetal cellular
repair mechanisms, and absorbed radiation dose level (ICRP, 2000; McCollough
et al., 2007).
(185) It is unlikely that radiation from diagnostic radiological examinations will
result in any known deleterious effects on the unborn child, but the possibility of
a radiation-induced effect cannot be ruled out entirely. However, for invasive pro-
cedures, the radiation dose to the fetus will vary, and can range from a very
small dose of little significance when the fetus is not in the primary beam, to a
significant dose when the fetus lies in the primary beam or adjacent to the pri-
mary beam boundary. This requires prospective planning. Radiation risks are
most significant during organogenesis and the early fetal period, somewhat less
significant in the second trimester, and least significant in the third trimester
(ICRP, 2000).
(186) As the Commission stated in Publication 84 (ICRP, 2000), analysis of many
of the epidemiological studies conducted on prenatal x-ray and childhood cancers

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are consistent with a relative risk of 1.4 (a 40% increase over the background risk)
following a fetal dose of approximately 10 mGy. The absolute risk estimate studies
indicate a risk of one cancer death per 1700 children exposed to 10 mGy in utero
(ICRP, 2000).
(187) Prenatal doses from most properly performed diagnostic procedures typ-
ically present no measurably increased risk of prenatal death, malformation, or
impairment of mental development over the background incidence of these enti-
ties. Typical fetal doses from selected x-ray procedures are presented in
Table 5.1.
(188) When the number of cells in the conceptus is small and their nature is not yet
specialised, the effect of damage to these cells is most likely to take the form of failure
to implant or undetectable death of the conceptus; malformations are unlikely or

Table 5.1. Typical fetal absorbed dose from x-ray examinations.

Examination Typical fetal dose (mGy) Reference*
Abdomen: antero-posterior 2.9 a
Abdomen: postero-anterior 1.3 a
Pelvis: antero-posterior 3.3 a
Chest <0.01 b
Lumbar spine (average for various 4.2 b
projections)
Hip joint 0.9 b
Intravenous pyelography (four images) 6 c
Intravenous urography 1.7–4.8 d
Small bowel study 7 c
Double contrast barium enema 7 c
Barium meal 1.5 b
Cholecystography 3.9 b
Abdominal CT, routine 4 c
Abdomen/pelvis CT, routine 25 c
Abdomen/pelvis CT, stone protocol 10 c
Endoscopic retrograde cholangio- 3.5–56 e
pancreatography
Pelvimetry 0.1–1.0 f
Fluoroscopically assisted surgical treatment 0.425 g
of hip
Sentinel lymph node biopsy <0.1 h
Fluoroscopically assisted surgical treatments 4 i
of spinal disorders (conceptus outside the
primary beam)
Fluoroscopically assisted surgical treatments 105 i
of spinal disorders (conceptus in primary
beam)
Transjugular intrahepatic portosystemic 5.5 j
shunt
CT, computer tomography.
* (a) UNSCEAR, 2010; (b) Osei and Faulkner, 1999; (c) McCollough et al., 2007; (d) ICRP, 2000; (e)

Samara et al., 2009; (f) Radiological Protection Institute of Ireland, 2010; (g) Damilakis et al., 2003; (h)
Pandit-Taskar et al., 2006; (i) Theocharopoulos et al., 2006; (j) Savage et al., 2007.

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very rare. Since organogenesis starts 3–5 weeks after conception, it is felt that radi-
ation exposure very early in pregnancy cannot result in malformation. The main risk
is fetal death, and a fetal dose of >100 mGy is needed for this to occur. Fetal doses in
excess of approximately 100 mGy may result in a decrease in the intelligence quotient
(IQ). Regardless of gestational age, IQ reduction cannot be clinically identified at fe-
tal doses of <100 mGy. It is also important to relate the magnitude of health effects
of ionising radiation to those abnormalities that occur spontaneously in the popula-
tion in the absence of radiation exposure other than natural background radiation
(ICRP, 2000).
(189) Occasionally, a patient will not be aware of a pregnancy at the time of
an x-ray examination, and will naturally be very concerned when the pregnancy
becomes known. In such cases, the radiation dose to the fetus/conceptus should
be estimated by a medical physicist or other professional experienced in dosim-
etry. The patient can then be better advised regarding the potential risks
involved.
(190) When a pregnant patient requires an x-ray procedure, the indications should
be evaluated to ensure justification. The procedure should then be optimised by strict
adherence to good technique, as described in Section 3.

5.2. Guidelines for patients undergoing radiological examinations/procedures at

childbearing age

(191) Prior to radiation exposure, female patients of childbearing age should be

evaluated, and an attempt should be made to determine individuals who are or could
be pregnant.
(192) Particular problems may be experienced in obtaining this information from
females under 16 years of age. There should be agreed procedures in place in all
clinical imaging facilities to cover this, and also to deal with unconscious patients
and those with special needs (Health Protection Agency, 2009). In addition, it
should not be forgotten that pregnancy can occur in adolescent girls; thus, precau-
tions for this group should be followed for exposures which may involve a fetus.
With this group, care and sensitivity must be exercised with regard to the circum-
stances in which they are asked the relevant questions, both to respect their privacy
and to optimise the possibility of being told the truth. With respect to pregnancy
tests, many are of little value in excluding early pregnancy and generate a false
sense of security.
(193) It is prudent to consider as pregnant any female of reproductive age present-
ing herself for an x-ray examination at a time when a menstrual period is overdue, or
missed, unless there is information that precludes a pregnancy (e.g. hysterectomy or
tubal ligation). In addition, every woman of reproductive age should be asked if she
is, or could be, pregnant. In order to minimise the frequency of unintentional radi-
ation exposures of the embryo and fetus, advisory notices should be posted in several
places in areas where x-ray equipment is used.
(194) As fetal doses are usually well below 50 mGy in x-ray procedures, pregnancy
tests are not usually performed. In cases where a high-dose fluoroscopy procedure of
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the abdomen or pelvis (e.g. embolisation) is contemplated, the physician may want
to order a pregnancy test depending on the reliability and history of the patient
(ICRP, 2000).
(195) If there is no possibility of pregnancy, the examination can be performed. If
the patient is definitely or probably pregnant, the justification for the proposed
examination must be reviewed, and the decision on whether to defer the investigation
until after delivery must be made, bearing in mind that a procedure of clinical benefit
to the mother may also be of indirect benefit to her unborn child, and that delaying
an essential procedure until later in pregnancy may present a greater risk to the fetus
(Health Protection Agency, 2009).
(196) When a patient has been determined to be pregnant or possibly pregnant, a
number of steps are usually taken prior to performing the procedure, as described in
Section 5.3.

5.3. Guidelines for patients known to be pregnant

(197) Medical exposure of pregnant women poses a different benefit/risk situation

than most other medical exposures. In most medical exposures, the benefit and risk
are to the same individual. In the situation of in-utero medical exposure, two differ-
ent entities (the mother and the fetus) must be considered (ICRP, 2000).
(198) Medical radiation applications should be optimised to achieve the clinical
purposes with no more radiation than is necessary, given the available resources
and technology. If possible, for pregnant patients, medical procedures should be tai-
lored to reduce fetal dose. Prior to and after medical procedures involving high doses
of radiation on pregnant patients, fetal dose and potential fetal risk should be esti-
mated (ICRP, 2000).
(199) Termination of pregnancy at fetal doses of <100 mGy is not justified based
upon radiation risk. At higher fetal doses, informed decisions should be made based
upon individual circumstances (ICRP, 2000).

5.4. Occupational exposure and pregnancy

(200) It is the Commission’s policy that methods of protection at work for wo-
men who are pregnant should provide a level of protection for the embryo/fetus
that is broadly similar to that provided for members of the public. The Commis-
sion recommends that the working conditions of a pregnant worker, after declara-
tion of pregnancy, should be such as to ensure that the additional dose to the
embryo/fetus would not exceed approximately 1 mSv during the remainder of
the pregnancy. The restriction of a dose of 1 mSv to the embryo/fetus of a preg-
nant worker after declaration of pregnancy does not mean that it is necessary
for a pregnant woman to avoid work with radiation completely, or that she must
be prevented from entering or working in designated radiation areas. It does, how-
ever, imply that the employer should review the exposure conditions of pregnant
women carefully (ICRP, 2007a).

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(201) There are many situations in which the worker may wish to continue doing
the same job, or the employer may depend on her to continue in the same job in or-
der to maintain the level of patient care that the work unit is customarily able to pro-
vide. From a radiological protection point of view, this is perfectly acceptable
provided that the fetal dose can be estimated reasonably accurately and falls within
the recommended limit of 1 mGy fetal dose after the pregnancy is declared. It would
be reasonable to evaluate the work environment in order to provide assurance that
high-dose accidents are unlikely (ICRP, 2000).
(202) The recommended dose limit applies to the fetal dose and is not directly
comparable to the dose measured on a personal dosimeter. A personal dosimeter
worn by diagnostic radiology workers may overestimate fetal dose by an approxi-
mate factor of 10 or more. If the dosimeter has been worn outside a lead apron,
the measured dose is likely to be approximately 100 times higher than the fetal dose
(ICRP, 2000).
(203) Finally, factors other than radiation exposure should be considered in eval-
uating the activities of pregnant workers. In a medical setting, there are often
requirements for lifting patients and for stooping or bending below knee level. A
number of national groups have established non-radiation-related guidelines for
such activities at various stages of pregnancy (ICRP, 2000).
(204) The position of the Commission is that discrimination should be avoided
based on radiation risks during pregnancy; if a pregnant woman wishes to con-
tinue her work in a fluoroscopy guided procedures laboratory, this should be al-
lowed with the following conditions: (a) she should do it on a voluntary basis
and confirm that she has understood the information provided on radiation risks;
(b) a specific dosimeter should be used at the level of the abdomen to monitor the
dose to the fetus monthly, and the worker should be informed of the dose values:
(c) a radiological protection programme should exist in the hospital or clinic,
supervised by a medical physicist or equivalent competent expert; (d) the worker
should know the practical methods to reduce her occupational dose, including use
of the existing radiological protection tools; (e) the worker should try to control
the workload in fluoroscopy guided procedures during her pregnancy; and (f) the
worker should know the risk of potential exposures and how to reduce their
probability. It should be noted that Points (d), (e), and (f) should be part of a
radiological protection programme, and Point (d) is applicable irrespective of
pregnancy.

5.5. Procedures in children

(205) X-ray procedures in children involve a different spectrum of disease condi-

tions specific to the very young child, and some conditions common in the adult pop-
ulation. The data derived from UNSCEAR estimates suggest that approximately 250
million paediatric radiological examinations (including dental) were performed
worldwide each year between 1997 and 2007 (UNSCEAR, 2010). Children undergo-
ing these examinations require special attention because of the diseases specific to
childhood and the additional risks to them. In addition, they also need special care,
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both in the form of care provided by parents and carers, and additional care pro-
vided by specially trained personnel.
(206) In the last 15 years, particular issues that arise in protecting children under-
going radiological examinations have come to the consciousness of a gradually wid-
ening group of concerned professionals and members of the public (Sidhu et al.,
2009; Strauss et al., 2010). There are many reasons for this, not least the natural in-
stinct to protect children from unnecessary harm. There is also their known addi-
tional sensitivity to radiation damage, and potentially longer lifetime in which
disease due to radiation damage may become manifest. Their sensitivity to cancer
induction is considered to be three to five times higher than that in adults (ICRP,
2007a).
(207) Children, particularly those with life-threatening disease in very early life,
are at the greatest risk as a consequence of the substantial radiation doses they incur
during investigations. These children may subsequently develop leukaemia within a
few years as a result of the irradiation of bone marrow, and breast cancer or thyroid
cancer as a result of chest or neck irradiation (ICRP, 2000).
(208) Therefore, the justification and optimisation principles are even more impor-
tant when children are exposed to ionising radiation (ICRP, 2007a). The Commis-
sion recommended a multi-step approach to justification of patient exposures in
Publication 105 (ICRP, 2007b). Optimisation of radiological protection in child
examinations should be generic for the examination type and all the equipment
and procedures involved. It should also be specific for the individual in order to re-
duce dose for the particular paediatric patient.
(209) It is important that the equipment used for paediatric imaging is well de-
signed and suited for the purpose for which it is applied. This is best ensured by hav-
ing an appropriate procurement policy that includes rigorous specification of what is
required, and verification that this is what the supplier delivers. In addition, it re-
quires a good quality control programme to ensure that the equipment continues
to be both functional and safe throughout its life, and involvement of the medical
physicist in dose optimisation and audit, particularly for higher dose procedures per-
formed in children.

5.5.1. Levels of radiation dose

(210) At present, approximately 15% of all fluoroscopy procedures and <1% of

interventional procedures performed in the USA are performed on paediatric pa-
tients (NCRP, 2009). There is a lack of published information on patient dose levels
for children undergoing x-ray procedures outside the imaging department. There-
fore, in addition to examinations performed outside the imaging department, typical
dose levels for patients of different ages undergoing radiological examinations are
presented in Table 5.2 for the purpose of comparison. However, the introduction
of new imaging technologies has, in some instances, resulted in increased use of pae-
diatric imaging, influencing the age profile for the examinations performed
(UNSCEAR, 2010).

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Table 5.2. Patient dose levels for various radiological examinations in children (Martinez et al., 2007;
Righi et al., 2008; Molina López et al., 2008; Calama Santiago et al., 2008; UNSCEAR, 2010).
Examination Age (years) Entrance surface Dose–area product Effective
dose (mGy) (mGy cm2) dose (mSv)
Abdomen PA 0 0.11 n.a. 0.10–1.3
1 0.34 n.a.
5 0.59 n.a.
10 0.86 n.a.
15 2.0 n.a.
Chest AP/PA 0 0.06 n.a. 0.005
1 0.080 n.a.
5 0.11 n.a.
10 0.070 n.a.
15 0.11 n.a.
Pelvis AP 0 0.17 n.a. n.a.
1 0.35 n.a.
5 0.51 n.a.
10 0.65 n.a.
15 1.30 n.a.
Skull AP 1 0.60 n.a. n.a.
5 1.2 n.a.
Skull LAT 1 0.34 n.a. n.a.
5 0.58 n.a.
MCU (micturating 0 n.a. 430 0.8–4.6
cysto-urethrogram) 1 n.a. 810
5 n.a. 940
10 n.a. 1640
15 n.a. 3410
Barium meal 0 n.a. 760 n.a.
1 n.a. 1610
5 n.a. 1620
10 n.a. 3190
15 n.a. 5670
Cardiac interventions <1 46 19 2.1–12
(various)
Percutaneous treatment n.a. n.a. n.a. 18
of varicocele
Biliary drainage with 1–3 35–50 1500–2300 0.9–1.5
bilioplasty
Pieloureteral surgery 5 20 n.a. 0.36
(per min fluoroscopy)
Varicocele embolisation 14 250 60,000 8.8
AP, antero-posterior; PA, postero-anterior; LAT, lateral; n.a., not available.

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 ICRP Publication 117

(211) Data on paediatric doses are very difficult to analyse because the height
and weight of children is very dependent on age. In addition, it is inappropriate
to use effective dose to quantify patient dose levels for paediatric and neonatal
imaging. As further explained in Annex A, when planning the exposure of pa-
tients and risk/benefit assessments, the equivalent dose – or preferably, the ab-
sorbed dose to irradiated tissues – is the more relevant quantity. This is
particularly true when risk estimates are intended. In order to compare centres,
an agreement was reached within the European Union to collect data for five
standard age groups: newborn, 1-year-old, 5-year-old, 10-year-old, and 15-year-
old children (UNSCEAR, 2010).
(212) The main issue following childhood exposure at typical diagnostic levels (a
few to a few tens of mGy) is cancer induction. It should be emphasised that interven-
tional procedures lead to higher doses to patients than conventional diagnostic inves-
tigations. The Commission covered this topic extensively in Publication 85 (ICRP,
2001).
(213) As a general principle, parents or family members should support the child
during any radiological examination. The reported effective dose level for parents
present in the room during x-ray examination of a child are typically 4–7 lSv
(Mantovani and Giroletti, 2004).

5.5.2. Radiation dose management

(214) All dose management actions described in Section 3 also apply for x-ray
examinations of children. Examination parameters must be tailored to the child’s
body size. For children, dose reduction is achieved by using technical factors specific
for children, and not using routine adult factors (Sidhu et al., 2009). Techniques to
reduce patient dose are very much the same as for adult examinations and include:
(a) no grids; (b) collimation solely to the irradiation volume of interest; (c) extra
beam filtration (extra Al or Cu filters); (d) low pulsed fluoroscopy; (e) reducing mag-
nification; (f) large distance between the x-ray tube and the patient, and short dis-
tance between the patient and the detector; and (g) digital subtraction
angiography and road-mapping techniques in fluoroscopy which can save contrast
medium and patient dose. In x-ray procedures in children, care should be taken to
minimise the radiation beam to affect the area of interest alone. Thus, collimation
is even more important for children (Section 3.3.2). One should always reduce the
irradiation beam to the organ/organs of interest and nothing else in order to reduce
the dose. With the automatic brightness control used in the equipment, this could
result in a slightly higher dose within the field, but a lower effective dose and better
image quality.
(215) In the exposure of comforters and carers (parents holding a child during
examination), dose constraints are applicable to limit inequity and because there
is no further protection in the form of a dose limit (ICRP, 2007b). Parents must
be provided with suitable radiological protection tools, and be informed about
the need for their protection prior to supporting their child during the
examination.
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5.6. References

Calama Santiago, J.A., Penedo Cobos, J.M., Molina López, M.Y., et al., 2008. Paediatric varicocele
embolization dosimetric study. Acta Urol. Esp. 32, 833–842.
Damilakis, J., Theocharopoulos, N., Perisinakis, K., et al., 2003. Conceptus radiation dose assessment
from fluoroscopically assisted surgical treatment of hip fractures. Med. Phys. 30, 2594–2601.
Health Protection Agency, 2009. Protection of Pregnant Patients During Diagnostic Medical Exposures to
Ionising Radiation; Advice from the Health Protection Agency, the Royal College of Radiologists and
the College of Radiographers. HPA, Chilton, UK.
ICRP, 2000. Pregnancy and medical radiation. ICRP Publication 84. Ann. ICRP 30(1).
ICRP, 2001. Avoidance of radiation injuries from medical interventional procedures. ICRP Publication
85. Ann. ICRP 30(2).
ICRP, 2007a. The 2007 Recommendations of the International Commission on Radiological Protection.
ICRP Publication 103. Ann. ICRP 37(2–4).
ICRP, 2007b. Radiological protection in medicine. ICRP Publication 105. Ann. ICRP 37(6).
Mantovani, A., Giroletti, E., 2004. Evaluation of the dose to paediatric patients undergoing
micturating cystourethrography examination and optimization of the examination. Radiol. Med.
108, 283–291.
Martinez, L.C., Vañó, E., Gutierrez, F., et al., 2007. Patient doses from fluoroscopically guided cardiac
procedures in paediatrics. Phys. Med. Biol. 21, 4749–4759.
McCollough, C.H., Schueler, B.A., Atwell, T.D., et al., 2007. Radiation exposure and pregnancy: when
should we be concerned? RadioGraphics 27, 909–918.
Molina López, M.Y., Calama Santiago, J.A., Penedo Cobos, J.M., et al., 2008. Evaluation of radiological
risk associated to pieloureteral surgery in paediatric patients. Cir. Pediatr. 21, 143–148.
NCRP, 2009. Ionizing Radiation Exposure of the Population of the United States. NCRP Report 160.
National Council on Radiation Protection and Measurements, Bethesda, MD.
Osei, E.K., Faulkner, K., 1999. Fetal doses from radiological examinations. Br. J. Radiol. 72, 773–
780.
Pandit-Taskar, N., Dauer, L.T., Montgomery, L., et al., 2006. Organ and fetal absorbed dose estimates
from 99mTc-sulfur colloid lymphoscintigraphy and sentinel node localization in breast cancer patients.
J. Nucl. Med. 47, 1202–1208.
Righi, D., Doriguzzi, A., Rampado, O., et al., 2008. Interventional procedures for biliary drainage with
bilioplasty in paediatric patients: dosimetric aspects. Radiol. Med. 113, 429–438.
Radiological Protection Institute of Ireland, 2010. Guidelines on the Protection of the Unborn Child
During Diagnostic Medical Exposures. Radiological Protection Institute of Ireland.
Samara, E.T., Stratakis, J., Enele Melono, J.M., et al., 2009. Therapeutic ERCP and pregnancy: is the
radiation risk for the conceptus trivial? Gastrointest. Endosc. 69, 824–831.
Savage, C., Patel, J., Lepe, M.R., et al., 2007. Transjugular intrahepatic portosystemic shunt creation for
recurrent gastrointestinal bleeding during pregnancy. J. Vasc. Interv. Radiol. 18, 902–904.
Sidhu, M.K., Goske, M.J., Coley, B.J., et al., 2009. Image gently, step lightly: increasing radiation dose
awareness in pediatric interventions through an international social marketing campaign. J. Vasc.
Interv. Radiol. 20, 1115–1119.
Strauss, K.J., Goske, M.J., Kaste, S.C., et al., 2010. Image gently: ten steps you can take to optimize
image quality and lower CT dose for pediatric patients. AJR Am. J. Roentgenol. 194, 868–873.
Theocharopoulos, N., Damilakis, J., Perisinakis, K., et al., 2006. Fluoroscopically assisted surgical
treatments of spinal disorders: conceptus radiation doses and risks. Spine 31, 239–244.
UNSCEAR, 2010. Sources and Effects of Ionizing Radiation. UNSCEAR 2008 Report. United Nations,
New York.

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 6. TRAINING

 A training programme in radiological protection for healthcare professionals has to

be oriented towards the type of practice in which the target audience is involved.
 A worker’s competency to carry out a particular function should be assessed by indi-
viduals who are suitably competent themselves.
 The main purpose of training is to make a qualitative change in practice that helps
operators use radiological protection principles, tools, and techniques to reduce their
own exposure without cutting down on work, and to reduce patient exposure without
compromising on image quality or intended clinical purpose. The focus has to remain
on achievement of skills. Unfortunately, in many situations, it takes the form of com-
plying with requirements of number of hours. While number of hours is an important
way to provide a yardstick, actual demonstration of skills to reduce occupational and
patient exposure is an essential part. In large parts of the world, clinical profession-
als engaged in fluoroscopy outside the imaging department have either no training or
inadequate training. The Commission has recommended that the levels of education
and training should be commensurate with the level of radiation use (ICRP, 2009).
 Legislation in most countries requires that individuals who take responsibility for
medical exposures must be properly trained in radiological protection.
 Training activities in radiological protection should be followed by an evaluation of
the knowledge acquired from the training programme (a formal examination
system).
 Physicians who have completed training should be able to demonstrate that they pos-
sess the knowledge specified by the curriculum by passing an appropriate certifying
examination.
 Nurses and other healthcare professionals who assist during fluoroscopic procedures
should be familiar with radiation risks and radiological protection principles in order
to minimise their own exposure and that of others.
 Medical physicists should become familiar with the clinical aspects of the specific
procedures performed at the local facility.
 Training programmes should include both initial training for all incoming staff, and
regular updating and retraining.
 Scientific congresses should include refresher courses on radiological protection,
attendance at which could be a requirement for continuing professional development.
 The issue of delivery of training has been dealt with in a recent publication (ICRP,
2009) and the text has been drawn from this publication.

6.1. Introduction

(216) In Publication 75, the Commission requires the provision of relevant and
adequate information on, and training in, radiological protection. This should be re-
garded as an essential component of the programme of implementation of the prin-
ciple of optimisation of protection in the control of both normal and potential
exposures (ICRP, 1997).

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(217) Despite the extensive and routine use of ionising radiation in their clinical
practice, physicians worldwide typically have little or no training in radiological pro-
tection. Traditionally, medical students do not receive training in radiological pro-
tection during medical school. Medical professionals who subsequently specialise
in radiological specialties, such as diagnostic radiology, nuclear medicine, and radio-
therapy, are taught radiological physics and radiological protection as part of their
specialty training. In many countries, there is no radiological protection education
during training in other specialties that form the target audience of this publication.
(218) In the past, training in radiological physics and radiological protection was
not necessary for non-radiologists, as x-rays and other radiation sources were only
used in imaging departments by staff with a reasonable amount of training in radio-
logical protection. Although x-ray fluoroscopy has been in use for more than a cen-
tury, its early application involved visualisation of body anatomy, movement of
structures, or passage of contrast media through the body. Radiologists normally
performed these procedures. When fluoroscopically guided procedures were intro-
duced, other specialists began to perform these procedures. Initially, they did so
jointly with radiologists in imaging departments. Over the years, equipment has been
installed in other clinical departments and outpatient facilities, and this is used by
non-radiologists without the participation of a radiologist. These non-radiologists
have not been subject to the training requirements of radiological physics and radio-
logical protection that are mandatory for radiologists. It is now clear that this train-
ing is essential; hence the need for specific guidance for these specialists.
(219) The Commission has addressed the specifics of training for interventional-
ists, nuclear medicine specialists, medical physicists, nurses, and radiographers/tech-
nologists, among others, in Publication 113 (ICRP, 2009).

6.2. Curriculum

(220) Conventional training programmes use a structure that is curriculum based.

There is a fundamental difference between training methodologies employed in non-
medical subjects and in medical, or rather clinical, subjects. While much of the train-
ing in sciences such as physics or biology is based on knowledge transmission, there
is much greater emphasis in clinical training on imparting skills to solve day-to-day
problems. A training programme in radiological protection for healthcare profes-
sionals has to be oriented towards the type of practice with which the target audience
is involved. Lectures should deal with essential background knowledge and advice
on practical situations, and the presentations should be tailored to clinical situations
to impart skills in the appropriate context. Practical training should be in a similar
environment to that in which the participants will be practising, and should provide
the knowledge and skills required for performing clinical procedures. It should deal
with the full range of issues that the trainees are likely to encounter (ICRP, 2009).
For further details, the reader is referred to Publication 113 (ICRP, 2009).

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Radiological Protection in Fluoroscopically Guided Procedures Performed Outside the Imaging Department

6.3. Who should be the trainer?

(221) The primary trainer in radiological protection should normally be an expert

in radiological protection in the practice with which he or she is dealing (normally a
medical physicist). In other words, a person with knowledge about clinical practice in
the use of radiation, the nature of radiation, the way in which it is measured, how it
interacts with the tissues, what type of effects it can lead to, principles and philoso-
phies of radiological protection, and international and national guidelines. As radio-
logical protection is covered by legislation in almost all countries of the world,
awareness of national legislations and the responsibilities of individuals and organ-
isations is essential (ICRP, 2009).
(222) In many situations, the radiological protection trainer may lack the knowl-
edge of practicalities, and may talk from an unrealistic standpoint relating to idea-
lised or irrelevant situations. The foremost point in any successful training is that
the trainer should have a clear perception about the practicalities in the work that
the training has to cover. It should deal with what people can practice in their
day-to-day work. Many trainers in radiological protection cannot resist the tempta-
tion of dealing with basic topics such as radiation units, interaction of radiation with
matter, and even structure of the atom and atomic radiations in more depth and de-
tail than is appropriate for this audience and for the practical purposes of this train-
ing. Such basic topics, while being essential in educational programmes, should only
be dealt with to a level such that they make sense. A successful trainer will not be too
focused on definitions which are purely for academic purposes, but will be guided by
the utility of the information to the audience. The same applies to regulatory require-
ments. The trainer should speak the language of users to convey the necessary infor-
mation without compromising on the science and regulatory requirements. Health
professionals who use radiation in day-to-day work in hospitals and impart the radi-
ation dose to patients have knowledge about the practical problems in dealing with
patients who may be very sick. They understand problems with the radiation equip-
ment they deal with, the time constraints for dealing with large numbers of patients,
and the lack of radiation measuring and radiological protection tools. Inclusion of
lectures from practising clinicians to dwell on good and bad radiological protection
practices is strongly recommended. It may be useful for the radiological protection
trainer to be on hand during such lectures to comment and discuss any issues raised
(ICRP, 2009).

6.4. How much training?

(223) Most people and organisations follow the relatively easy route of prescribing
the number of hours. The Commission gives some recommendations on the number
of hours of education and training; this should act as a simple guideline, rather than
be applied rigidly (ICRP, 2009). This has advantages in terms of implementation of
training and monitoring the training activity, but is only a guide.
(224) The issue of how much training is given should be linked with the evaluation
methodology. One has to be mindful about the educational objectives of the training
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(i.e. acquiring knowledge and skills). Many programmes are confined to providing
training without assessing the achievement of the objectives. Although some pro-
grammes have pre- and post-training evaluations to assess the knowledge gained,
fewer training programmes assess the acquisition of practical skills. Using modern
methodologies of online examination, results can be determined instantaneously.
It may be appropriate to encourage development of questionnaire and examination
systems that assess knowledge and skills, rather than prescribing the number of
hours of training. Due to the magnitude of the requirement for radiological protec-
tion training, it may be worthwhile for organisations to develop online evaluation
systems. The Commission is aware that such online methods are currently available,
mainly from organisations that deal with large-scale examinations. The development
of self-assessment examination systems is encouraged to allow trainees to use them in
the comfort of the home, on a home PC, or anywhere where the internet is available.
The Commission recommends that evaluation should have an important place
(ICRP, 2009).
(225) The amount of training depends upon the level of radiation employed in the
work, and the probability of occurrence of overexposure to the patient or workers.
For example, radiotherapy employs the delivery of several Gy of radiation per pa-
tient, and a few tens of Gy each day to groups of patients. Interventional procedures
could also deliver skin doses in the range of a few Gy to specific patients. The level of
radiation employed in radiography practice is much lower than the above two exam-
ples, and the probability of significant overexposure is lower, unless the wrong pa-
tient or wrong body part is irradiated. The radiation doses to patients from CT
examinations are also relatively high, and thus the need for radiological protection
is correspondingly greater. Another factor that should be taken into account is the
number of times that a procedure such as CT may be repeated on the same patient.
(226) The training given to other medical specialists such as vascular surgeons,
urologists, endoscopists, and orthopaedic surgeons before they direct fluoroscopi-
cally guided invasive techniques is significantly less or even absent in many countries.
Radiological protection training is recommended for physicians involved in the
delivery of a narrow range of nuclear medicine tests relating to their speciality.

6.5. Recommendations on training

(227) Training for healthcare professionals in radiological protection should be re-

lated to their specific jobs and roles.
(228) The physicians and other health professionals involved in procedures that
irradiate patients should always be trained in the principles of radiological protec-
tion, including the basic principles of physics and biology (ICRP, 2007a).
(229) The final responsibility for radiation exposure lies with the physician provid-
ing the justification for the exposure being carried out, who should therefore be
aware of the risks and benefits of the procedures involved (ICRP, 2007b).
(230) Education and training, appropriate to the role of each category of physi-
cian, should be given at medical schools, during residency, and in focused specific
courses. There should be an evaluation of the training, and appropriate recognition
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 Radiological Protection in Fluoroscopically Guided Procedures Performed Outside the Imaging Department

that the individual has completed the training successfully. In addition, there should
be corresponding radiological protection training requirements for other clinical per-
sonnel who participate in the conduct of procedures utilising ionising radiation, or in
the care of patients undergoing diagnosis or treatment with ionising radiation
(ICRP, 2007b).
(231) Scientific and professional societies should contribute to the development of
the syllabuses, and to the promotion and support of the education and training. Sci-
entific congresses should include refresher courses on radiological protection, atten-
dance at which could be a requirement for continuing professional development for
professionals using ionising radiation.
(232) Professionals involved more directly in the use of ionising radiation should
receive education and training in radiological protection at the start of their career,
and the education process should continue throughout their professional life as the
collective knowledge of the subject develops. It should include specific training on
related radiological protection aspects as new equipment or techniques are intro-
duced into a centre.
(233) Nurses and other healthcare professionals who assist during fluoroscopic
procedures should be familiar with radiation risks and radiological protection prin-
ciples in order to minimise their own exposure and that of others.
(234) Medical physicists should become familiar with the clinical aspects of the
specific procedures performed at the local facility.
(235) Training programmes should include both initial training for all incoming
staff, and regular updating and retraining.

6.6. References

ICRP, 1997. General principles for the radiation protection of workers. ICRP Publication 75. Ann. ICRP
77(1).
ICRP, 2007a. The 2007 Recommendations of the International Commission on Radiological Protection.
ICRP Publication 103. Ann. ICRP 37(2–4).
ICRP, 2007b. Radiological protection in medicine. ICRP Publication 105. Ann. ICRP 37(6).
ICRP, 2009. Education and training in radiological protection for diagnostic and interventional
procedures. ICRP Publication 113. Ann. ICRP 39(5).

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 7. RECOMMENDATIONS

 There is a need to rectify the neglect of radiological protection coverage to facil-

ities outside the control of imaging departments.
 There is high radiation risk to workers and patients in fluoroscopy facilities out-
side imaging departments, primarily due to the lack of radiological protection
training of workers in many countries.
 A number of procedures, such as EVAR, renal angioplasty, iliac angioplasty, ure-
teric stent placement, therapeutic ERCP, and bile duct stenting and drainage,
involve radiation levels exceeding the threshold for skin injuries. If due attention
is not given, radiation injuries to patients are likely to occur in the future.
 Many patients require regular and repeated radiation exposure for many years,
and quite a few patients will require this for life. In some cases, the effective dose
for each year of follow-up has been estimated to be a few tens of mSv. Unfortu-
nately, this has not received the attention it needs. The Commission recommends
that urgent attention should be given to application of justification and optimisa-
tion of protection to achieve the lowest exposure consistent with the desired clin-
ical outcomes.
 Workers should be familiar with the radiation dose quantities used in fluoroscopy
equipment to represent patient dose.
 Modern sophisticated equipment requires understanding of features that have
implications for patient dose and how patient dose can be managed.
 For fluoroscopy machines in operating theatres, there are specific problems that
make the use of radiation shielding screens for workers’ protection more difficult,
but not impossible. Such occupational protective measures should be used.
 Manufacturers should develop shielding screens that can be used for protection of
workers using fluoroscopy machines in operating theatres without hindering the
clinical task.
 Manufacturers should develop systems to indicate patient dose indices with the
possibility of producing patient dose reports that can be transferred to the hospi-
tal network.
 Manufacturers are encouraged to develop devices that provide representative
occupational doses without the need for extensive cooperation of staff.
 Health professionals involved in procedures that irradiate patients should always
be trained in radiological protection. The Commission recommends a level of
radiological protection training commensurate with radiation use.
 Medical professionals should be aware about their responsibilities as set out in
regulations.
 Scientific and professional societies should contribute to the development of train-
ing syllabuses, and to the promotion and support of education and training. Sci-
entific congresses should include refresher courses on radiological protection,
attendance at which could be a requirement for continuing professional develop-
ment for professionals using ionising radiation.

95
 ANNEX A. DOSE QUANTITIES AND UNITS

(A1) Dosimetric quantities are needed to assess radiation exposures to humans in

a quantitative way. This is necessary in order to describe dose–response relationships
for the health effects of ionising radiation, which provide the basis for setting protec-
tion standards as well as for the quantification of exposure levels.
(A2) Absorbed dose in tissue is the energy absorbed per unit mass in a body tissue.
The unit of absorbed dose is joule per kilogram (J/kg), whose special name is gray
(Gy). It is assumed that the mean value of absorbed dose in an organ or tissue is cor-
related with radiation detriment from stochastic effects in the low-dose range. The
averaging of absorbed doses in tissues and organs of the human body and their
weighted derivatives are the basis for the definition of protection quantities.
(A3) The protection quantities are used for risk assessment and risk management
to ensure that the occurrence of stochastic effects is kept below unacceptable levels
and tissue reactions are avoided. The average absorbed dose to an organ or tissue
is called ‘organ absorbed dose’ or simply ‘organ dose’.
(A4) The equivalent dose to an organ or tissue is the organ dose multiplied by a
radiation weighting factor that takes account of the relative biological effectiveness
of the radiation relevant to the exposure. This radiation weighting factor is numer-
ically 1 for x rays. The equivalent dose has the same SI unit as that of absorbed dose,
but it is called ‘sievert’ (Sv) to distinguish between them.
(A5) For medical exposures, the assessment of stochastic risk is complex as more
than one organ is irradiated. The Commission has introduced the quantity ‘effective
dose’ as a weighted sum of equivalent doses to all relevant tissues and organs, in-
tended to indicate the combination of different doses to several different tissues in
a way that is likely to correlate well with the sum of the stochastic effects. This is
therefore applicable even if the absorbed dose distribution over the human body is
not homogeneous. The effective dose has the same unit and special name as equiva-
lent dose (i.e. J/kg and Sv).
(A6) While absorbed dose in a specified tissue is a physical quantity, the equivalent
dose and effective dose include weighting factors which are based on radiobiological
and epidemiological findings. The main and primary use of effective dose is to pro-
vide a means of demonstrating compliance with dose limits in occupational and pub-
lic exposures. In this sense, effective dose is used for regulatory purposes worldwide.
Effective dose is used to limit the occurrence of stochastic effects (cancer and genetic
effects), and is not applicable to the assessment of the possibility of tissue reactions.
(A7) The use of effective dose for assessing the exposure of patients has severe lim-
itations that must be taken into account by medical professionals. Effective dose can
be of value for comparing doses from different diagnostic procedures, in a few special
cases from therapeutic procedures, and for comparing the use of similar technologies
and procedures in different hospitals and countries, as well as using different technol-
ogies for the same medical examination. For planning the exposure of patients and
risk/benefit assessments, however, the equivalent dose – or preferably, the absorbed

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dose to irradiated tissues – is the more relevant quantity. This is especially the case
when risk estimates are intended (ICRP, 2007).
(A8) Collective dose is a measure of the total amount of effective dose multiplied
by the size of the exposed population. Collective dose is usually expressed in terms of
person-Sv.

A.1. Quantities for assessment of patient doses

(A9) Air kerma (kinetic energy released in a mass) is the sum of the initial kinetic
energies of all electrons released by the x-ray photons per unit mass of air. For the
photon energies used in x-ray procedures, the air kerma is numerically equal to the
absorbed dose free in air, except where there is no equilibrium of secondary electrons
such as in air in the vicinity of an interface. The unit of air kerma is J/kg or Gy
(ICRU, 2005; IAEA, 2007).
(A10) A number of earlier publications have expressed measurements in terms of
the absorbed dose to air. Recent publications point out the experimental difficulty in
determining the absorbed dose to air, especially in the vicinity of an interface; in real-
ity, what the dosimetry equipment registers is not the energy absorbed from the radi-
ation by the air, but the energy transferred by the radiation to the charged particles
resulting from the ionisation. For these reasons, ICRU (2005) recommends the use
of air kerma rather than absorbed dose to air, which applies to quantities determined
in air, such as the entrance surface air kerma (rather than entrance surface air dose)
and the kerma–area product (rather than DAP). Notwithstanding this remark, the
quantities ‘DAP’ and ‘entrance surface dose’, both in air, have been retained in some
places in this report, as they appear in the given references and readers are more
familiar with them.
(A11) In diagnostic radiology, the incident air kerma ðK i Þ is often used. This is the
air kerma from the incident beam on the central x-ray beam axis at focal spot-to-skin
distance (i.e. at skin entrance plane). Incident air kerma can be calculated from the x-
ray tube output, where output is measured using a calibrated ionising chamber
(ICRU, 2005).
(A12) Entrance surface air kerma ðK e Þ is the air kerma on the central x-ray beam
axis at the point where the x-ray beam enters the patient. The contribution of back-
scatter radiation is included through backscatter factor (B), thus: K e ¼ B  K i . The
backscatter factor depends on the x-ray spectrum, the x-ray field size, and the thick-
ness and composition of the patient or phantom. Typical values of backscatter factor
in diagnostic and interventional radiology are in the range of 1.2–1.6 (ICRU, 2005).
The unit for entrance surface air kerma is the Gy. Entrance surface air kerma can be
calculated from incident air kerma using suitable backscatter factor, or determined
directly using small dosimeters (thermoluminescent or semiconductor) positioned
at the representative point on the skin of the patients.
(A13) Incident air kerma and entrance surface air kerma are recommended quan-
tities for establishment of diagnostic reference levels in projection radiography, or to
assess maximal skin dose in interventional procedures (ICRU, 2005).

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Radiological Protection in Fluoroscopically Guided Procedures Performed Outside the Imaging Department

(A14) The incident and entrance surface air kerma do not provide information on
the extent of the x-ray beam. However, the air kerma–area product ðP KA Þ, as the
product of air kerma and area A of the x-ray beam in a plane perpendicular to
the beam axis, provides such information.
(A15) The common unit for air kerma–area product is Gycm2. The P KA has the
useful property of being approximately invariant with distance from the x-ray tube
focal spot. It can be measured in any plane between the x-ray source and the patient
using specially designed transparent ionising chambers mounted at the collimator
system or, in digital systems, calculated using data of the generator and the digitally
recorded jaw position (ICRP, 2001). The air kerma–area product is the recom-
mended quantity to establish diagnostic reference levels in conventional radiography
and complex procedures including fluoroscopy. It is helpful in dose control for sto-
chastic effects to patients and operators (ICRP, 2001).
(A16) In radiology, it is common practice to measure a radiation dose quantity
that is then converted into organ doses and effective dose by means of conversion
coefficients. These coefficients are defined as the ratio of the dose to a specified tissue
or effective dose divided by the normalisation quantity. Incident air kerma, entrance
surface air kerma, and kerma–area product can be used as normalisation quantities.
Conversion coefficients to convert air kerma–area product or entrance surface kerma
to effective dose for selected procedures are given in Table A.1.

A.2. Quantities for occupational dose assessment

(A17) Dose limits for occupational exposures are expressed in equivalent doses for
tissue reactions in specific tissues, and expressed as effective dose for stochastic effects
throughout the body. When used for tissue reactions, equivalent dose is an indicator
of whether or not the threshold for the tissue reaction is being approached.
(A18) Occupational dose limits are recommended by the Commission (ICRP,
1991, 2007) for stochastic effects (dose limits for effective dose) and tissue reactions
(dose limits for equivalent dose to the relevant tissue). As presented in Table 2.1,
dose limits are given in mSv. For x-ray energies in diagnostic and interventional pro-
cedures, the numerical value of the absorbed dose in mGy is essentially equal to the
numerical value of the equivalent dose in mSv.
(A19) The main radiation source for workers is the patient’s body, which scatters
radiation in all directions during fluoroscopy and radiography. A personal dosimeter
should be worn, and the dose determined can be used as a substitute for the effective
dose. To monitor doses to the skin, hands and feet, and lens of the eye, special
dosimeters (e.g. ring dosimeter) should be used (ICRP, 2001). The instruments used
for dose measurement are commonly calibrated in terms of operational quantities,
defined for practical measurement and assessment of effective and equivalent dose
(ICRU, 1993).

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 Table A.1. Conversion coefficients to convert air kerma–area product and entrance surface kerma to effective dose for adults in selected x-ray procedures
(European Commission, 2008; NCRP, 2009; Health Protection Agency, 2010).
Group Examination Conversion Conversion coefficient Conversion coefficient Conversion
coefficient (mSv/Gy cm2) (mSv/Gy cm2) coefficient (mSv/mGy)
(mSv/Gy cm2) (European (Health Protection (Health Protection
(NCRP, 2009) Commission, 2008) Agency, 2010) Agency, 2010)
Urinary and renal studies Cystography 0.18
Excretion urography, 0.18
micturating cysto-
urethrography
Antegrade pyelography 0.18

ICRP Publication 117

Nephrostography 0.18
Retrograde pyelography 0.18
Intravenous urography 0.18
100

Endoscopic retrograde 0.26

cholangio-pancreatography
Orthopaedics and joints 0.01
Femur AP 0.036 0.023
Femur LAT 0.0034 0.002
Knee AP 0.0034 0.001
Knee LAT 0.003 0.001
Foot (dorsiplantar) 0.0032 0.001
Foot (oblique) 0.0032 0.001
Obstetrics and gynaecology Pelvimetry 0.29
Hysterosalpingography 0.29
Renal Retrograde pyelography 0.18
Nephrostography 0.18
Barium meal 0.2
Barium enema 0.28
Line missing
 Radiological Protection in Fluoroscopically Guided Procedures Performed Outside the Imaging Department
Table A.1. (continued )
Group Examination Conversion Conversion coefficient Conversion coefficient Conversion
coefficient (mSv/Gy cm2) (mSv/Gy cm2) coefficient (mSv/mGy)
(mSv/Gy cm2) (European (Health Protection (Health Protection
(NCRP, 2009) Commission, 2008) Agency, 2010) Agency, 2010)
Barium follow 0.22
Cardiac angiography 0.2
Percutaneous transluminal 0.26
angioplasty
Stents Renal/visceral percutaneous 0.26
transluminal angioplasty
(all) with stent;
Iliac percutaneous transluminal
angioplasty (all) with stent;
Bile duct, dilation and stenting
101

Radiography Chest (PA + LAT) low kVp 0.10

Chest (PA + LAT) high kVp 0.18 0.158/0.125 0.131/0.090
Thoracic spine 0.19 0.244/0.093 0.094/0.031
Lumbar spine 0.21 0.224/0.092 0.116/0.027
Abdomen 0.26 0.180 0.132
Pelvis 0.29 0.139 0.099
Hip 0.29 0.13 0.064
Skeletal survey Average of arms, legs, skull LAT, 0.09
lumbar spine LAT, chest AP,
abdomen/pelvis AP
Whole spine/scoliosis Average of thoracic and 0.22
lumbar spine AP
Average of cervical, thoracic and 0.16
lumbar spine (AP + lateral)

AP, antero-posterior; PA, postero-anterior; LAT, lateral.

 ICRP Publication 117

A.3. References

European Commission, 2008. European Guidance on Estimating Population Doses from Medical X-Ray
Procedures. Radiation Protection 154. European Commission, Luxembourg.
Health Protection Agency, 2010. Frequency and Collective Dose for Medical and Dental X-ray
Examinations in the UK, 2008. HPA-CRCE-012. Health Protection Agency, Chilton.
IAEA, 2007. Dosimetry in Diagnostic Radiology: an International Code of Practice. IAEA Technical
Report Series 457. IAEA, Vienna.
ICRP, 1991. 1990 Recommendations of the International Commission on Radiological Protection. ICRP
Publication 60. Ann. ICRP 21(1–3).
ICRP, 2001. Avoidance of radiation injuries from medical interventional procedures. ICRP Publication
85. Ann. ICRP 30(2).
ICRP, 2007. The 2007 Recommendations of the International Commission on Radiological Protection.
ICRP Publication 103. Ann. ICRP 37(2–4).
ICRU, 1993. Quantities and Units in Radiation Protection Dosimetry. ICRU Report 51. ICRU Bethesda,
MD.
ICRU, 2005. Patient Dosimetry for X-rays Used for Medical Imaging. ICRU Report 74. ICRU Bethesda,
MD.
NCRP, 2009. Ionizing Radiation Exposure of the Population of the United States. NCRP Report 160.
National Council on Radiation Protection and Measurements, Bethesda, MD.

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