1. Introduction to nuclear medicine technology NMT 231
Aya Ahmed Saeed

2. Radiation Protection

3. Radiation is a Tool Radiation has many wonderful uses Diagnose disease
Cure cancer
Analytical tools for industry and medicine
Sterilize medical equipment and food, etc
Like anything, it can be misused, and
Like anything, too much is not good for you L4

4. Is there a safe point? If not, how to deal with the problem?
Ionizing Radiation
We live with
1-3 (10) mSv/y
(Back ground)
Can kill
4000 mSv
Is there a safe point? If not, how to deal with the problem? L4
21L2

5. Objectives of Radiation Protection
PREVENT occurrence of deterministic effects
Cataracts
Skin burns
Transient hematopoietic
Necrosis
etc,
MINIMIZE the probability of stochastic effects
cancer
genetic L4

6. Systems of Protection Achieving objectives requires:
Source-related rules: how to maximize benefits from use of technology while maintaining individual related rules (minimum time, use maximum distance and shielding)
Individual-related rules: dose limit for maximum safety
Based upon 3 principles:
Justification: Benefit of a practice must offset (outweigh, be
more than) the radiation detriment
Optimization: Exposures and likelihood of exposure should be
ALARA kept as low as reasonably achievable, (economic
and social factors being taken into account)
Limitation: limits for protection of workers and public.
These Principles apply when dealing with all potentially harmful
substances or technologies (chemicals, traffic, sports etc.), requiring:
Clear benefit lowest possible risk tolerable limits
تبرير الإستخدام
الإستخدام الأمثل
وضع حدود L4

7. Principles of Radiation Protection
SYSTEM
Justification
Benefit>risk
Optimization
ALARA
Limitation/constraints
Numerical dose limits
Principle Principle Principle 3
Order of application of principles L4

8. Principles of Radiation Protection
Justification
In medicine, we must not give a person a radiation exposure unless there is good reason, and the person will benefit from the procedure
For workers, the public and for patients, any unnecessary exposure must be avoided

9. Principles of Radiation Protection
Limitation
the ICRP specify dose limits which must not be exceeded
Dose limits are NOT a permitted limit
Dose limits are designed to avoid deterministic effects, and to limit the occurrence of stochastic effects to acceptable levels

10. Principles of Radiation Protection
Optimizations
as well as ALARA (As Low As Reasonably Achievable), dose limits may be reduced by using additional constraints where justified.

11. Radiation Protection Can Be Simple

12. Basic Safety Precautions (1)
Time - more time near source means more dose
Shielding -appropriate use of shielding materials
Distance - inverse square law

13. Basic Safety Precautions (2)
Inverse square law
radiation from a point source decreases by the square of the distance
Dose is proportional to 1/(distance)2
ie. twice the distance gives 1/4 the dose, but half the distance gives 4 times the dose

15. Basic Safety Precautions (3)
Shielding :
Use of high atomic number and high density materials eg. lead, concrete, steel
Normal building materials eg. brick, mortar, wallboard, can be either very poor shielding materials, or have very variable and unpredictable properties

16. Shield Position and Size
Always work behind shields (shield material and thickness depends on type of radiation emitted and quantity being handled)
Shield source:
you protect everybody
Shield person:
you protect one body L4

17. Guidelines
Recording Levels: levels at which values received should be entered in worker records. الحد الأدنى لتعرض العامل الواجبة التسجيل
Investigation levels: values above which investigation is to be conducted. حد تعرض العامل يجب بعدها إجراء تحقيق لمعرفة الأسباب
Action level: dose rate or activity concentration above which remedial actions are necessary
حد الجرعة أو التلوث الذى يستوجب إتخاذ إجراءات تصحيحية
Reference Levels of Medical Exposure: Exposure of patients above this level is assumed to result in an unnecessarily excessive dose for the purpose,يعتبر تعرض المريض فوق هذا المستوى تعرضاً غير مبرر
Intervention levels IL: levels at which intervention and counter measures should be carried out. (IL is also known as Protective Action Guides PAG or Emergency Reference Levels ERL)
مستوى تعرض يستوجب التدخل وإتخاذ إجرآت على وجه السرعة
Cost Benefit Analysis: an optimization procedure setting exposures where efforts for further reduction cannot be justified. L4

18. Controlled Area: Supervised area:
An area where it is necessary to follow special procedures to restrict exposure to ionizing radiation, or
An area where any person is likely to receive 3/10th of the dose limit or more
Supervised area:
Any area where it is necessary to keep conditions under review, or
An area where it is possible for a person to receive a dose > 1 mSv/y or 1/10th the dose limit. L4

19. Local Rules
Anyone entering a controlled area must either be a classified worker, or a patient who have read and/or understood the local rules
Usually, new employees must read and sign to say they have read the local rules before they are allowed to enter a controlled area.
They must learn how to:
Protect patients
Protect yourself
Protect other workers
Protect the environment
Requirement of Monitoring L4

20. CONTAMINATION
Part 5. Occupational Protection

21. Contamination of the worker
Part 5. Occupational protection
Radiation protection in nuclear medicine
Contamination of the worker
Spills
Improper administration
Experimental work with animals
Emergency surgery of a therapy patient
Autopsy of a therapy patient
Part 5. Occupational Protection

22. Part 5. Occupational protection
Radiation protection in nuclear medicine
To minimize contamination risks adopt clean operating conditions adopt good laboratory practices do not eat, smoke etc… use protective gloves and clothing
Part 5. Occupational Protection

23. Part 5. Occupational protection
Radiation protection in nuclear medicine
PROTECTIVE CLOTHING
The image to the right is an example of clothing if the preparation of radiopharmaceuticals have to be done in a sterile environment
Appropriate clothing should as a minimum include lab coat and gloves.National regulations may require more.
Part 5. Occupational Protection

24. DECONTAMINATION PROCEDURES
Part 5. Occupational protection
Radiation protection in nuclear medicine
DECONTAMINATION PROCEDURES
Use adsorbent paper on wet spill or wet absorbent
paper on dry spill
Repetitively swab the area inwards towards the center
of the spill
Place contaminated paper in a plastic bag or container
Monitor the area
Repeat the procedure until the exposure rate is below
given limits
If the decontamination is not successful, mark the
contaminated area and classify the room as a controlled
area If not already done) until the contamination is
completely removed.
Part 5. Occupational Protection

25. Decontamination of skin
Part 5. Occupational protection
Radiation protection in nuclear medicine
Decontamination of skin
If contamination of the skin occurs, immediately the area should be thoroughly washed using mild soap and tepid (not hot) water.
Particular care should be paid to cleaning under the fingernails.
If this does not bring the contamination to an acceptably low level the procedure should be repeated using a decontaminating detergent.
Scrub with a nail brush but take care not to break the skin.
Part 5. Occupational Protection

26. Thanks