radiation safety in nuclear medicine for Nurses.pptx

radiation safety in nuclear medicine for Nurses

1. Radiation Safety Jay Prakash Kumar Scientific Officer ‘C’ & RSO Department of Nuclear Medicine MPMMCC(A Unit of Tata Memorial Centre)

2. What is radiation? Form of energy Emitted by nucleus of atom or orbital electron Released in form of electromagnetic waves or particles

3. TYPES OF RADIATION Ionizing radiation Radiation that has sufficient energy to dislodge orbital electrons cause ionization in the medium through which it passes Eg : alpha particle, beta particle, x-rays, gamma rays, neutrons Non ionizing radiation A type of low energy radiation that doesn’t have enough energy to remove an electron from an atom or molecules. Eg :- radio waves, microwaves, radar, infrared, visible light, ultraviolet.

4. Penetrating power of Radiation

5. Radiation is OMNIPRESENT

6. We and Radiation! We can’t see it We can’t feel it. We can’t smell it If exposed to High radiation May Cause vomiting,diarrhea,cancer,genetic damage ,death Its's effect may not show up immediately May appear –this decade, this generation, next generation There is no marker to tell damage was caused by radiation

7. Ionization Chamber

8. Proportional counter

9. Radiation Detector (G M Counter)

10. Personal radiation protection instrument

11. Principle of Radiation protection Justification Justification means that any dose of exposure must have a benefit to exposed individuals or society   process of justification allows determining whether the medical exposure will take place or not.

12. Optimization Optimization means that minimum risk and maximum benefit (should be achieved). Optimization means that doses should be ‘as low as reasonably achievable’ (ALARA).

13. Optimization of protection ALARA concept ALARA stands for A s L ow A s R easonably A chievable Refers to the continual application of the optimization principle in the day-to-day practice Because of some risk, however small, exists from any radiation dose, all doses should be kept ALARA. Includes reducing both internal and external radiation dose. ALARA is the responsibility of all employees .

14. How to achieve ALARA? Cardinal principles of radiation protection, Basic protective actions taken to minimize external dose include: Minimizing time in radiation areas Maximizing the distance from a source of radiation Using shielding whenever possible Reducing the amount of radioactive material (source reduction)

15. Time An ALARA principle is to reduce the time in a radiation field 100 200 300 mrem 100 mrem / hr 1 hour 2 hours 3 hours

16. Distance Effective & Easy Inverse Square Law I∝1/d 2 Doubling distance from source, decreases dose by factor of four Tripling it decreases dose nine-fold More Distance = Less Radiation Exposure

17. Shielding Barriers of lead, concrete or water can stop radiation or reduce radiation intensity.

18. Dose limit • The dose limit is determined by the law based on the protection standards recommended by the ICRP/AERB • This is not the boundary between safety and danger. Individual doses from all relevant practices should not exceed specified dose limits.

19. Basis of Dose Limits Risk based approach : For radiation workers : The death rate probability is 1 out of 1000. This death rate probability is equal to the death rate probability of the workers working in high risk areas in a safe industry. For the public the risk is considered to be 1/10 th of the workers The average dose received by a radiation worker is below 1 mSv/annum i.e. below 1/20 th of the prescribed limit Note: The risk is estimated on the basis of Linear No Threshold (LNT) Model. The deleterious effects of ionising radiation is yet to established at low doses. The genetic effects w.r.t. radiation exposure in human beings is yet to be established.

20. System of Radiological Protection Type of exposure situations Planned exposures Emergency exposures Existing exposure situations Categories of exposures Occupational exposure Public exposure Medical exposure Identification of exposed individuals Workers Members of public Patients and comforters

21. Categories of Exposure… Occupational Exposure : Rradiation exposure of workers incurred as a result of their work during use of radiation sources (radioactive material and radiation generating equipment). Dose Limit: As per AERB Directive 01/2011

22. Adult Occupational Dose Limits Whole Body (everything except extremities) 30 mSv maximum per year 20 mSv averaged over 5 years Extremities 500 mSv per year Skin of the Whole Body 500 mSv per year Lens 150 mSv (New limit 20 mSv/y)

23. Categories of Exposure… Public Exposure : Public exposure encompasses all exposures of the public other than occupational exposures and medical exposures of patients.

24. Public Dose Limits Whole Body (everything except extremities) 1 mSv per year Skin of the Whole Body 50 mSv per year Extremities 50 mSv per year Lens 15 mSv

25. Annual average exposures (mSv) for the year 2014 in India Source/Practice Average annual effective dose (mSv) Diagnostic X- rays 0.8 Radiation therapy 0.55 Nuclear Medicine 0.9 Industrial Radiography and Radiation processing 1.41 Research 0.37

26. Categories of Exposure… Medical Exposure : As per RPR 2004 M edical exposure means exposure incurred by - patients as part of their own medical diagnosis or treatment; persons, other than occupationally exposed, while knowingly and willingly helping in the support and comfort of patients; and volunteers in biomedical research.

27. Categories of Exposure… Medical Exposure : Dose limits do not apply to medical exposures. Diagnostic reference levels Dose constraints for comforters and carers ???

28. Dose constraints for comforters and visitors of patients: 5 mSv for adults and 1 mSv for children. Diagnostic Reference levels / Guidance Levels (R adiography, Fluoroscopy, CT & Cardiology procedures, Nuclear Medicine)

29. Radiation protection