Technical principles of
medical instruments
Ch1. Introduction
INTRO
Medical devices are different in designs and complexity.
• They can be:
✓ Simple as a tongue depressor ()خافض اللسان,
✓ Compact as pacemaker ()جهاز تنظيم ضربات القلب,
✓ Sophisticated ( )متطورas a surgical robot ()روبوت جراحي.
• medical devices use similar technology as their commercial
applications, but different in many fundamental
Classification of Medical Devices
There are many different approaches to classify or group medical
devices.
Devices can be grouped by:
1. functions,
2. Physical Parameters,
3. Principles of Transduction,
4. Physiological Systems,
5. Clinical Medical Specialties,
6. Risk Classes
Classification of Medical Devices
1- Classified by Functions
• Grouping medical devices by function is by far the most common
way to classify medical devices.
• Devices can be separated into two main categories:
✓ Diagnostic ()تشخيصي
✓ Therapeutic ()عالجي.
Classification of Medical Devices
1- Classified by Functions
Diagnostic Devices:
• are used to determine physical signs, diseases and/or injury
without alteration of the structure and function of the biological
system.( أو اإلصابة دون تغيير في هيكل ووظيفة/ تستخدم لتحديد العالمات الجسدية واألمراض و
.)النظام البيولوجي
• some devices may alter the biological system to a certain extent
due to their applications. “monitoring devices”( قد تعمل بعض األجهزة على
"أجهزة المراقبة.)تغيير النظام البيولوجي إلى حد معين بسبب تطبيقاتها
• The main purpose of this class of devices is trending, absolute
accuracy ( الدقة المطلقة، )الغرض الرئيسي من هذه الفئة من األجهزة هو االتجاه
Classification of Medical Devices
1- Classified by Functions
Diagnostic Devices:
• For example:
✓ A computer tomography scanner “impose ionization
radiation on the human body”.( ماسح تصوير مقطعي للحاسوب "يفرض
.")إشعاع التأين على جسم اإلنسان
✓ heart rate monitors used to detect variation of heart rates
during a course of drug therapy,
✓ noninvasive blood pressure monitors to watch arterial blood
pressure immediately after surgery.
Classification of Medical Devices
1- Classified by Functions
Therapeutic Devices:
• Group I: Are designed to effect structural or functional changes
that lead to improved overall function of the patient.
• Examples:
✓ electrosurgical units in surgery,( وحدات الجراحة الكهربائية في
)الجراحة
✓ linear accelerators in cancer treatment
“Radiotherapy”(“)مسرعات خطية في عالج السرطان "العالج اإلشعاعي
✓ infusion devices in fluid management therapy.( أجهزة الحقن
.)في العالج إدارة السوائل
Classification of Medical Devices
1- Classified by Functions
Therapeutic Devices:
• Group II: Are used to restore an existing function of the human
body. They may be considered a subset of therapeutic devices.
• Examples:
✓ pacemakers,
✓ hearing aids,
✓ wheelchairs.
• Based on the methods of application, these device classes can be
invasive or noninvasive, automatic or manual.
Classification of Medical Devices
2- Classified by Physical Parameters
Medical devices can also be grouped by the physical parameters that
they are measuring.
For example:
✓ blood pressure monitor is a pressure monitoring device,
✓ airway spirometer is a flow measurement device,
✓ tympanic thermometer is a temperature-sensing device.
Classification of Medical Devices
3- Classified by Principles of Transduction
Some medical devices are grouped according to the types of
transducers used at the patient-machine interface such as:
✓ Resistive,
✓ Inductive,
✓ Ultrasonic,
✓ Magnetic.
Classification of Medical Devices
4- Classified by Physiological Systems
Medical devices may also be grouped by their related human
physiological systems.( يمكن أيضًا تجميع األجهزة الطبية حسب األنظمة الفيزيولوجية البشرية ذات
.)الصلة
Examples:
✓ cardiovascular devices(:)أجهزة القلب واألوعية الدموية
➢ blood pressure monitors
➢ electrocardiographs
✓ pulmonary devices: (:)األجهزة الرئوية
➢ Respirators ()أجهزة التنفس
➢ mechanical ventilators
Classification of Medical Devices
Spirometer
Respirator Respirometer
()مقياس التنفس
()أجهزة التنفس ()مقياس التنفس
Spirometry is the most
common of the
Respirometer is a device
pulmonary function tests.
used to measure the rate
It measures lung function,
of respiration of a living
specifically the amount
Respirator is a device organism by measuring its
and/or speed of air that
designed to protect the rate of exchange of
can be inhaled and
wearer from inhaling oxygen and/or carbon
exhaled.( هو أكثر االختبارات
particulate matter( هو dioxide.( هو جهاز يستخدم
يقيس وظيفة.عا ً الوظيفية شيو
جهاز مصمم لحماية مرتديها لقياس معدل التنفس للكائن الحي
أو سرعة/ وتحديد كمية و، الرئة
)من استنشاق الجسيمات عن طريق قياس معدل تبادل
الهواء التي يمكن استنشاقها
أو ثاني أكسيد/ األكسجين و
.)وزفيرها
.)الكربون
Classification of Medical Devices
5- Classified by Clinical Medical Specialties
according to the medical specialties (such as pediatrics, obstetrics,
etc.) in which they are being used.(، والتوليد، وفقا للتخصصات الطبية (مثل طب األطفال
.)وما إلى ذلك) التي يتم استخدامها فيها
example,
✓ obstetric device: a fetal monitor( جهاز رصد الجنين:)جهاز التوليد
✓ radiological device: x-ray machine.(. جهاز األشعة السينية:)جهاز إشعاعي
Classification of Medical Devices
5- Classified by Risk Classes
For biomedical engineers and regulatory personnel, medical devices
are often referred to by their risk class.
Risk classes are created to differentiate devices by rating their risk
level on patients.
Canadian Medical Device Regulations. Similar risk classifications are
used in the United States and Europe.
Next Lecture:
• The medical device is called electrocardiograph,
• The record of the electrical cardiac potential as a function of time
is called the electrocardiogram.
• The first ECG came into clinical use in the 1920s
Cardiovascular system
• Champers
• Valves
Next Lecture:
Circulatory system
• Blood pathway
Thanks for listening…
Any questions
??!!
