1. Part 2

2. What can radiation do? Death Cancer Skin Burns Cataract Infertility
Genetic effects 2

3. What can radiation do? Deterministic effects
death, skin burns, cataract,
infertility
Stochastic effects
cancer, genetic effects 3

4. Early Observations of the Effects of Ionizing Radiation
Part No 3, Lesson No 1
Biology
Early Observations of the Effects of Ionizing Radiation
X Rays discovered by Roentgen
First skin burns reported
First use of X Rays in the treatment of cancer
Becquerel: Discovery of radioactivity
First cases of skin damage reported
First report of X Ray induced cancer
First report of leukaemia in humans and lung cancer from occupational exposure
cases of tumour reported in Germany (50 being radiologists)
IAEA Training Material: Radiation Protection in Radiotherapy

5. OBJECTIVES OF RADIATION PROTECTION
PREVENTION of deterministic effect.
LIMITING the probability of stochastic effect 5

6. Radiosensitivity [RS]
RS = Probability of a cell, tissue or organ of suffering an effect per unit of dose.

7. Part 1. Biological effects of ionizing radiation
Radiation Protection in Nuclear Medicine
RADIOSENSITIVITY:
High RS
Medium RS
Low RS
Gonads
Thyroid
Eye lens
Bone Marrow
Spleen
Lymphatic nodes
Lymphocytes
Skin
Mesoderm organs (liver, heart, lungs…)
Muscle
Bones
Nervous system

8. Why do we need protection?
Part No...., Module No....Lesson No
Part 3. Principles. International framework
Radiation protection in nuclear medicine
Module title
Why do we need protection?
It is generally assumed that even very small doses of ionizing radiation can potentially be harmful .
Therefore, persons must be protected from ionizing radiation at all dose levels.
This follows from the linear no-threshold hypothesis for stochastic effects 8
IAEA Post Graduate Educational Course in Radiation Protection and Safe Use of Radiation Sources

9. Who should be protected in Hospital?
Patients.
Members of his/her family.
Workers.
General public. 9

10. Ionizing Radiation
We live with
1-3 mSv/y
Can kill
4000 mSv 10

11. Part No...., Module No....Lesson No
Module title
Patients Protection:
Persons are medically exposed as part of their diagnostic or treatment
According to IAEA, ICRP and BSS, two basic principles of radiation protection are to be complied with:
justification and optimization
Explanation or/and additional information
Instructions for the lecturer/trainer
IAEA Post Graduate Educational Course in Radiation Protection and Safe Use of Radiation Sources

12. RP Principles vs. Actions
Justification
Optimization
Dose Limitations
Time
(dose directly proportional to length of exposure).
Shielding
(b/w source and patient).
Distance
(Intensity and StP distance).

13. Justification
No use of ionizing radiation is justified if there is no benefit.
All applications must be justified.
This implies: All, even the smallest exposures are potentially harmful and the risk must be offset by a benefit. 13

14. The justification of a practice
The decision to adopt or continue any human activity involves a review of benefits and disadvantages of the possible options
E.g.: choosing between the use of X Rays or ultrasound
Most of the assessments needed for the justification of a practice are made on the basis of experience, professional judgement, and common sense.

15. Risk/Benefit analysis:
Need to evaluate the benefits of radiation - an easy task in the case of nuclear medicine.
Radiation is the diagnostic and therapeutic agent.
Assessment of the risks requires the knowledge of the dose received by persons. 15

16. Part No...., Module No....Lesson No
Part 3. Principles. International framework
Radiation protection in nuclear medicine
Module title
Optimization
When radiation is to be used then the exposure should be optimized to minimize any possibility of detriment.
Optimization is “doing the best you can under the prevailing conditions”.
Need to be familiar with techniques and options to optimize the application of ionizing radiation - this is really the main objective of the present course.
This is a very important slide as it summarizes the aim of the material:
If optimization is doing the best one can under prevailing conditions, it is essential to know the conditions very well. The knowledge of these conditions (and constraints) also helps to avoid controversy. 16
IAEA Post Graduate Educational Course in Radiation Protection and Safe Use of Radiation Sources

17. Optimization:
Reducing the patient dose may reduce the quantity as well as the quality of the information provided by the examination or may require important extra resources.
Means that doses should be “As Low As Reasonably Achievable” ALARA, economic and social factors being taken into account” compatible with achieving the required objective.

18. Optimization principle ALARA
Part 3. Principles. International framework
Part No...., Module No....Lesson No
Radiation protection in nuclear medicine
Module title
Optimization principle ALARA
The lecturer should point out that:
a) Acronyms are always a shortening of the actual problem and may create confusion
b) BSS deliberately avoids the use of the acronym ALARA - it is mentioned here because it is so widely used, but should be avoided
c) It is essential to also include the second part of the statement: “keeping in mind …” 18
IAEA Post Graduate Educational Course in Radiation Protection and Safe Use of Radiation Sources

19. OPTIMIZATION OF PATIENT EXAMINATION
Part 6. Medical exposure
Part No...., Module No....Lesson No
Radiation protection in nuclear medicine
Module title
OPTIMIZATION OF PATIENT EXAMINATION
Optimization of medical exposure means a proper balance between the diagnostic objective and radiation burden for the patient
Diagnostic objective Medical exposure
IAEA Post Graduate Educational Course in Radiation Protection and Safe Use of Radiation Sources

20. Optimization of image quality
Part 6. Medical exposure
Part No...., Module No....Lesson No
Radiation protection in nuclear medicine
Module title
Optimization of image quality
Image quality depends on:
Administered activity
Technical factors - equipment used - acquisition protocol - image processing & evaluation - noise - spatial resolution
- scatter
Patient factors - size
- age
- disease - movement
IAEA Post Graduate Educational Course in Radiation Protection and Safe Use of Radiation Sources

21. Framework of RP for medical exposure
Justification
Optimization
The use of doses limits is NOT APPLICABLE
Dose constraints and guidance (or reference) levels ARE RECOMMENDED

22. Three types of exposure
Medical Exposure (principally the exposure of persons as part of their diagnostic or treatment)
Occupational Exposure (exposure incurred at work, and practically as a result of work)
Public Exposure (including all other exposures)

23. Medical exposure Medical Exposure
Exposure of persons as part of their diagnostic or treatment.
Exposures incurred by volunteers as part of a program of biomedical research.

24. Responsibilities for Medical Exposure
Part No...., Module No....Lesson No
Part 3. Principles. International framework
Radiation protection in nuclear medicine
Module title
Responsibilities for Medical Exposure
(a) No patient to be administered a diagnostic or therapeutic medical exposure unless the exposure is prescribed by a medical practitioner;
(d) For therapeutic uses of radiation, the calibration, dosimetry and quality assurance requirements of the Standards be conducted by or under the supervision of a qualified expert in radiotherapy physics.
The insert shows one of the first diagnostic X-rays ever taken.
Father Slattery exposed the hand of a boy who was accidentally shot by a shot gun in 1896 in Australia. This resulted in taking the gun shot out instead of amputating the hand as it would have been likely otherwise. The bright spots are the gun shot in the picture. 24
IAEA Post Graduate Educational Course in Radiation Protection and Safe Use of Radiation Sources

25. PUBLIC: effective dose of 1 mSv/year
equivalent dose to lens of the eye 15 mSv/yr
equivalent dose to skin of 50 mSv/year.

26. Guidance levels for diagnostic radiography (typical adult patient)
Examination
Entrance surface dose per radiograph (mGy)
Lumbar spine AP 10
Lumbar spine LAT 30
Lumbar spine LSJ 40
Abdomen, IVU and cholecystography AP

27. Guidance levels for diagnostic radiography (typical adult patient)
Examination
Entrance surface dose per radiograph (mGy)
Pelvis AP 10
Hip joint AP
Chest PA
0.4
Chest LAT
1.5

28. Typical effective doses from diagnostic medical exposures
procedure
Typical effective dose (mSv)
Equiv. no. of chest x-rays
Approx. equiv. period of natural background radiation
Chest (single PA film)
0.02 1
3 days
Skull
0.07
3.5
11 days
Thoracic spine
0.7 35
4 months
Lumbar spine
1.3 65
7 months
From: Referral Criteria For Imaging. CE, 2000.

29. Typical effective doses from diagnostic medical exposures
procedure
Typical effective dose (mSv)
Equiv. no. of chest x-rays
Approx. equiv. period of natural background radiation
CT head
2.3
115
1 year
CT chest 8
400
3.6 years
CT Abdomen or pelvis 10
500
4.5 years
From: Referral Criteria For Imaging. CE, 2000.

30. OCCUPATIONAL - APPENDIX I
Part No...., Module No....Lesson No
Part 3. Principles. International framework
Radiation protection in nuclear medicine
Module title
OCCUPATIONAL - APPENDIX I
Dose Limits
effective dose of 5mSv per year averaged over five consecutive years
equivalent dose to lens of eye of 150mSv in a year
equivalent dose to extremities or skin of 500mSv in a year.
For apprentices (16-18 years of age)
effective dose of 6mSv in a year
These are the dose limits for workers. 30
IAEA Post Graduate Educational Course in Radiation Protection and Safe Use of Radiation Sources

31. Part No...., Module No....Lesson No
Part 3. Principles. International framework
Part No...., Module No....Lesson No
Radiation protection in nuclear medicine
Module title
OCCUPATIONAL
Female workers should notify pregnancy.
Working conditions shall be adapted to ensure that the embryo and fetus are afforded the same broad level of protection as for members of the public. 31
IAEA Post Graduate Educational Course in Radiation Protection and Safe Use of Radiation Sources

32. Class Activity 3
Mr. Sharp, I am given to understand that 2 bone scans and a cardiac study done on me have given me 22 mSv whereas 20 mSv is the safe dose. I want to file legal suit against the doctor. What do you feel??