RADIATION
PROTECTION
PRESENTED BY: GROUP 2
TEN COMMANDMENTS OF RADIATION PROTECTION
1. Understand and apply the cardinal principles of radiation
control: time, distance, and shielding.
2. Do not allow familiarity to result in false security.
3. Never stand in the primary beam.
4. Always wear protective apparel when not behind a
protective barrier.
5. Always wear an occupational radiation monitor and
position it outside the protective apron at the collar.
TEN COMMANDMENTS OF RADIATION PROTECTION
6. Never hold a patient during radiographic examination. Use
mechanical restraining devices when possible. Otherwise,
have family or friends hold the patient.
7. The person who is holding the patient must always wear a
protective apron and, if possible, protective gloves.
8. Use gonadal shields on all people of childbearing age when
such use will not interfere with the examination.
9. Examination of the pelvis and lower abdomen of pregnant
patients should be avoided whenever possible, especially
during the first trimester.
10. Always collimate to the smallest field size appropriate for
the examination.
CARDINAL PRINCIPLES OF RADIATION PROTECTION
All health physics activity in radiology is designed to minimize the radiation
exposure of patients and personnel. Three cardinal principles of radiation
protection developed for nuclear activities—time, distance, and shielding—find
equally useful application in diagnostic radiology. When these cardinal principles are
observed, radiation exposure can be minimized (Box 35-1).
CARDINAL PRINCIPLES OF RADIATION PROTECTION
Time
Length or time of exposure.
Minimize Time.
Time is directly related to dose.
*If time is doubled, the dose is doubled.
*If time is halved, the dose is halved.
In radiography, the radiographer controls the time.
-EMPLOY THE SHORTEST POSSIBLE EXPOSURE TIME
In Fluoroscopy, the radiologist controls time
-using intermittent fluoro (which means off and on, not constantly on)
-and a 5 min reset timer to let radiologist know how long the beam is on, not a
limit.
CARDINAL PRINCIPLES OF RADIATION PROTECTION
Distance
Maintain as much distance as possible when concerned about radiation
protection.
Keep the maximum distance between you (or patient) and the source.
The Inverse Square Law represents the relationship of intensity to
distance:
CARDINAL PRINCIPLES OF RADIATION PROTECTION
Shielding
Placing shielding material between the radiation source and the person/s
exposed reduces the level of exposure.
Shielding for diagnostic radiology usually consist of lead and sometimes
concrete.
The amount of protective barrier needed to reduce the intensity of radiation
can be estimated by HVL or TVL.
For both the patient and the radiographer use the maximum shielding
possible (lead glass window, lead contact shield).
CARDINAL PRINCIPLES OF RADIATION PROTECTION
HVL (Half-Value Layers) TVL (Tenth-Value Layers)
The TVL is the thickness of
The HVL of an x-ray beam is
the material required to
the thickness of absorbing
reduce the x-ray beam’s
material necessary to reduce
intensity to one-tenth of its
the x-ray intensity to half of
original value.
its original value.
CARDINAL PRINCIPLES OF RADIATION PROTECTION
Shielding
Table 35-1 shows approximate HVLs
and TVLs for lead and concrete for
diagnostic x-ray beams between 40
and 150 kVp.
CARDINAL PRINCIPLES OF RADIATION PROTECTION
Cardinal Rules Working Together
Figure 35-3 illustrates the use
of these cardinal principles of
radiation protection during a
typical clinical situation.
CARDINAL PRINCIPLES OF RADIATION PROTECTION
Cardinal Rules Working Together
Use all three cardinal rules to determine exposure to personnel or
to the patient.
All three work together to find exposure received.
*When working a problem with cardinal rules, always be consistent and
work in order that address all three aspects of the cardinal rules.
1. First, address the time aspect which involves Exposure (exposure rate
x time (either mAs, hrs. or sec.)
2. Secondly, address distance (using the Inverse Square Law)
3. Thirdly, address the shielding cardinal rule.
4. Lastly, time allowed which is not always included - usually concerned
with dose and not time factor. (Time allowed is in days, hours, min, etc)
LEGAL AND ETHICAL RESPONSIBILITIES
LEGAL RESPONSIBILITIES (Minimum required by law)
Follow ALARA principle — mandated in many regulations.
Comply with regulations from:
*NCRP: dose limits, protection guidelines.
*NRC & state agencies: licensing, safety inspections.
Maintain credentials — valid ARRT/state license + CE credits.
Equipment compliance — ensure shielding, filtration, exposure
indicators work properly.
LEGAL AND ETHICAL RESPONSIBILITIES
LEGAL RESPONSIBILITIES (Minimum required by law)
Dosimetry & records — wear personal dosimeters, document
occupational doses.
Incident reporting — document and report
overexposures/malfunctions.
Informed consent — explain risks/benefits before exposure.
Scope of practice — do not perform procedures outside legal
competency.
LEGAL AND ETHICAL RESPONSIBILITIES
ETHICAL RESPONSIBILITIES (Professional & moral duty beyond the law)
Patient first — always prioritize safety and comfort.
Minimize exposure — use lowest dose possible for diagnostic quality.
Avoid repeats — ensure correct positioning, technique, and patient
instructions.
Respect autonomy — allow patients to refuse; do not pressure.
Maintain confidentiality — protect patient information (HIPAA).
LEGAL AND ETHICAL RESPONSIBILITIES
ETHICAL RESPONSIBILITIES (Professional & moral duty beyond the law)
Special Considerations - Children and Pregnant Women: Extra caution
due to higher sensitivity to radiation.
Beneficence and Non-Maleficence - Ensure the procedure benefits the
patient.
Avoid unnecessary radiation exposure (do not perform x-rays without
valid medical reason)
SYSTEM OF DOSE LIMITS
Principles of Justification
Principles of Optimization
Principles of Dose limits
PRINCIPLES OF JUSTIFICATION
The potential benefits of exposing the patient to
ionizing radiation must far outweigh the potential risk of
adverse biologic effects.
Assess the Benefits vs Risk of additional exposure of
an activity.
PRINCIPLES OF OPTIMIZATION
The exposure from a justified application of radiation
must follow the ALARA Rule.
This is achieved through the application of basic
principles of radiation exposure.
PRINCIPLE OF DOSE LIMITS
No one should get more than the recommended dose
limits (except patients with valid medical reasons).
DOSE LIMITATION
Numerical Limits
Recommended dose equivalent received under various
circumstances.
These limits are expected to produce no significant radiation effects.
RECOMMENDED DOSE LIMITS
CATEGORIES OF EXPOSURE
Occupational Exposure (Radiation Workers)
Public Exposure (General Public)
Patients undergoing Medical Exposure
Special Considerations
RECOMMENDED DOSE LIMITS
DOSE LIMITATION FOR OCCUPATIONAL WORKERS AND PUBLIC
TYPES OF LIMIT OCCUPATIONAL PUBLIC
Effective Dose 20 mSv/year 1 mSv/year
Lens of Eye 150 mSv/year 15 mSv/year
Skin 500 mSv/year 15 mSv/year
Hands and Feet 500 mSv/year 50 mSv/year
Pregnant Women 1 mSv/year 1 mSv/year
RECOMMENDED DOSE LIMITS
EFFECTIVE DOSE LIMIT RECOMMENDATION
EDUCATION AND TRAINING EXPOSURES
Annual 1 mSv or 0.01 rem
Lens of Eye 15 mSv or 1.5 rem
Skin 50 mSv or 5 rem
Hands and Feet 50 mSv or 5 rem
EMBRYO TO FETUS (PREGNANCY PERIOD) EXPOSURES
Monthly Dose Limit 0.5 mSv or 0.05 rem
Entire Gestational Period 5 mSv or 0.5 rem
RECOMMENDED DOSE LIMITS
Patients undergoing Medical Exposure
No fixed dose limits
Exposure is justified by benefits to the px health like diagnosis and
treatment
Focus is on Optimization (ALARA) and recommended dose levels to avoid
unnecessary exposure.
Special Considerations
Pregnant Radiation Workers: The fetus should not receive more than 1 mSv
Student/Trainees in Clinical Training: Effective DL is 6 mSv/year
CLASSIFICATION OF WORKING AREA
Controlled Area
An area occupied primarily by radiology personnel & patients.
Occupied by persons trained in radiation safety wearing PPEs.
DL: <1 mSv/week (100 mrem/week); Annual Recommended Occupational DL: 5000 mrem
or 50 mSv
Uncontrolled Area
An area that can be occupied by anyone
Areas open to the general public; not provided with dosimeter or radiation safety
training.
DL: <20 µSv/week; Annual Recommended Public DL: 100 mrem or 1 mSv
PROTECTIVE BARRIER: should ensure that no individual will receive more than 2.5 mrem/hr
or 25 µSv.hr.
