The ICRP System of Protection Applied to Medical Exposures

1. The ICRP System of ProtectionApplied to Medical Exposures Results from UNSCEAR & ICRP Recommendations South Africa -- 2009 April 15-17 Chris Clement ICRP Scientific Secretary

2. Overview • Why is radiological protection important in medical exposures? • The ICRP system of radiological protection in medicine

3. Why is radiological protection in medical exposures important?

4. Medical Exposures • The highest source of artificial exposure, by far • Average and collective doses increasing rapidly, particularly due to increasing use of CT From UNSCEAR

5. US NCRP Report 160, Radiation Exposure to the US Population

6. US NCRP Report 160, Radiation Exposure to the US Population

7. Medical Overexposures Whole body of baby exposed instead of chest only Brain damage from radiotherapy overexposure Overheated X-ray tube stopped cardiac procedure 18 months after cardiac catheteri-sation and stent placement

8. The ICRP system of radiological protection in medicine

9. System of Protection in Medicine • P 103: the complete system of protection • P 105: Radiological Protection in Medicine(replaces P 73) • P 80: Radiation Dose to Patients from Radiopharmaceuticals • P 84: Pregnancy and Medical Radiation • P 85: Avoidance of Radiation Injuries from Medical Interventional Procedures • P 86: Prevention of accidental exposures to patients undergoing radiation therapy

10. System of Protection in Medicine • P 87: Managing Patient Dose in Computed Tomography • SG 2: Radiation and your patient: A guide for medical practitioners • P 93: Managing patient dose in digital radiology • P 97: Prevention of high-dose-rate brachytherapy accidents • P 98: Radiation safety aspects of brachytherapy for prostate cancer using permanently implanted sources • P 102: Managing Patient Dose in Multi-Detector Computed Tomography (MDCT)

11. System of Protection in Medicine • P 106: Radiation Dose to Patients from Radiopharmaceuticals and in the works: • Minimising unintended exposure in radiation therapy from new technologies • Evaluation and management of secondary cancer risk in radiation therapy • Protecting Children in Paediatric Radiology

12. System of Protection in Medicine Justification • Benefit and most of the risk apply to the patient Optimization • ALARA in medicine is management of the radiation dose to the patient commensurate with the medical purpose • Diagnostic reference levels (not constraints) Dose Limitation • Does not apply to medical exposures (of patients)

13. Three Levels of Justification • Is the proper use of radiation in medicine doing more good than harm to society? • A specified procedure with a specified objective • e.g. chest x-ray for diagnostic purposes for patients showing relevant symptoms • Application to a specific patient • i.e. Do more good than harm to the patient

14. ‘Buy Our CT, Earn $ 2,163,000 in 5 Years’ INTERNATIONAL COMMISSION ON RADIOLOGICAL PROTECTION ——————————————————————————————————————

15. Gift Certificates for Radiation Exposure ???? INTERNATIONAL COMMISSION ON RADIOLOGICAL PROTECTION ——————————————————————————————————————

16. Even in South Africa! Maybe not all that bad... • “responsible ... low-dose screening” • “targeted scans of vital organs” • “does not perform unproven Full Body Scans” • “If you have risk factors...”

17. Optimization • Two levels of optimization: • The design, selection and construction of equipment and installations • The day-to-day methods of working • Keeping doses ALARA, economic and societal factors being taken into account • In medicine this is management of the radiation dose to the patient commensurate with the medical purpose

18. Optimization Doses can be too high • Non-optimised diagnostic equipment or methods (e.g. QA problems, limited access to, short-lived radiopharmaceuticals) • Non-optimised therapeutic equipment or methods (e.g. limited access to conformal therapy, inverse dose-planning) • Inadequate or insufficient training (e.g. over-utilisation of ‘boost’ options in digital radiology) Doses can be too low • The UK Computerised Treatment Planning accident, 1982-1991 • 1 045 patients affected, 5-30% under-dosage • 492 patients had a recurrence, believed to be caused by the under-dosage

20. Diagnostic Reference Levels • Detriments and benefits are received by the same individual, the patient • Dose is determined principally by medical needs • Dose constraints are therefore inappropriate • Diagnostic Reference Levels help evaluate whether a patient dose is unusually high or low for a particular procedure

21. Diagnostic Reference Levels (SG-2) • The concept: are my doses in line with those of my peers? • If not: Do I have a good reason? • DRLs should be set by regional / national / local bodies • One size does not fit all! • DRL numerical values are advisory • Implementation of the concept may be a legal requirement • DRLs should be easily measured • ESD, DAP, DLP, administered activity… • DRLs apply to groups, not to single patients

22. Paediatric RadiologyPoster & Sticker

23. Image Gently • Alliance for Radiation Safety in Pediatric Imaging (Society for Pediatric Radiology) • www.imagegently.org

24. Christopher Clement CHP Scientific Secretary International Commission on Radiological Protection PO Box 1046, Station B 280 Slater Street Ottawa, Ontario K1P 5S9 CANADA sci.sec@icrp.org www.icrp.org