1. Radiation Protection Omar Desouky Review article Submitted by:
Medical Biophysics Lab.
Radiation Physics Department
National Center for Radiation Research and Technology
Atomic Energy Authority (AEA)
2010

2. Natural 87% Manmade 13% Air 51% Misc. 0.3% Fallout 0.4% Medical 12%
Radon & Thoron
Cosmic 10%
Food 12%
Terrestrial 14%
Natural 87%
Manmade 13%
Misc. 0.3%
Fallout 0.4%
Occupational 0.2%
Nuclear 0.1%
Medical 12%

4. Fundamental principles of radiation protection
Justification of practices
Limitation of doses
Optimization of protection and safety

5. 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

6. 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

7. Risk/Benefit analysis
Need to evaluate the benefits of radiation - an easy task in the case of radiotherapy
Radiation is the therapeutic agent
Assessment of the risks requires the knowledge of the dose received by persons

8. ALARA Concept As Low As Reasonably Achievable
GOAL: decrease exposure whenever possible
does not eliminate radiation exposure
provides guidelines to limit the risk of body injury

9. Optimization principle

10. Dose limitation
No dose limitation for medical exposure of the patient - it is always assumed that the benefits for the patient outweigh the risks
Limits need to be applied for public and occupational exposures.

11. Basic radiation protection strategies
Radiation cannot be seen, heard or felt. Therefore it is essential to know about it.
Can be accurately measured using appropriate instruments
Need appropriately qualified expert

12. Basic radiation protection strategies
Radiation cannot be seen, heard or felt. Therefore it is essential to know about it.
Need signs and interlocks

13. Basic radiation protection strategies
Time
Distance
Shielding

14. Dose is proportional to
Time
Dose is proportional to
the time exposed
Dose = Dose-rate x Time

15. Distance Inverse square law (ISL): Dose-rate  1/(distance)2 dose-rate

16. Shielding
Barrier thickness
incident
radiation
transmitted
radiation

17. Summary
Humans must be protected from ionizing radiation at all dose levels
Exposure can occur in three different categories:
Occupational
Medical
Public

18. Summary The basic principles of a system of radiation protection are:
Dose limits to individuals
Optimization of protection
Justification of practices
Even simple measures such as reducing the time exposed to irradiation or keeping distance can be effective measures to reduce exposure

21. Dose
Severity
Dose
Probability

24. Accidental external or internal exposure
In considering the use of radioprotectors or therapeutic agents, it is necessary to distinguish the potential application
Accidental external or internal exposure
Acute high-dose radiation injury,
Environmental alpha-particle exposure to the lung,
Low-dose occupational exposure over a long time period, Military scenarios
Cosmic radiation exposures during space flight,
Radiotherapy protocols where protection of normal tissues and killing of tumor cells is required.
Uncontrolled exposures to radiation from nuclear accidents
potential terrorist incidents

25. Potential scenarios for human exposures may involve ingestion of radionuclides, such as isotopes of:
iodine,
strontium,
americium,
cesium,
plutonium,
Internal exposures of specific organs from ingested radionuclides are best treated initially by blocking agents such as
potassium iodide for iodine),
chelating agents (Ca DTPA and Zn DTPA for plutonium and americium

29. Alpha lipoic acid

30. Alpha lipoic acid against different oxidative stresses
The ability of α-lipoic acid to protect the hemoglobin against β-thalassemic disease oxidative damage and exposure to Gamma radiation (150 Gy) Desouky et al, 2008

31. Effect of lipoic acid on the oxidative stress of thalassemia
and gamma radiation

34. Alpha lipoic acid against different doses of gamma radiation

35. Alpha lipoic acid against different doses of gamma radiation
Changes in the EPR (S4) signal intensity for control, irradiated and irradiated
& α- lipoic acid of RBC.

36. Conclusion

37. Applications of radiation in biophysics cover
many fields
Radiation techniques are applied in diagnosis and treatment of many diseases.
Biophysical measurements are applied for monitoring the effects of radiation exposure as they reflect the missing detailed of the biochemical and biological processes on a molecular level.
Biophysical studies are involved in testing and developing radioprotective agents.

39. Thanks for attention