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Results from UNSCEAR & ICRP Recommendations South Africa -- 2009 April 15-17 Chris Clement ICRP Scientific Secretary Why is radiological protection important in medical exposures? The ICRP system of radiological protection in medicine 2 3 The highest source of artificial exposure, by far Source Global Average Dose (mSv per year) Occupational 0.005 Atmospheric Nuclear Testing 0.005 Chernobyl Accident 0.005 Medical Diagnosis 0.6 From UNSCEAR Average and collective doses increasing rapidly, particularly due to increasing use of CT 4 5 6 Brain damage from radiotherapy overexposure Whole body of baby exposed instead of chest only Overheated X-ray tube stopped 18 months after cardiac cathetericardiac procedure sation and stent placement 7 8 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 9 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) 10 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 11 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) 12 1. Is the proper use of radiation in medicine doing more good than harm to society? 2. A specified procedure with a specified objective e.g. chest x-ray for diagnostic purposes for patients showing relevant symptoms 3. Application to a specific patient i.e. Do more good than harm to the patient 13 INTERNATIONAL COMMISSION ON RADIOLOGICAL PROTECTION —————————————————————————————————————— INTERNATIONAL COMMISSION ON RADIOLOGICAL PROTECTION —————————————————————————————————————— 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...” 16 Two levels of optimization: 1. 2. 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 17 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 18 19 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 20 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 21 22 Alliance for Radiation Safety in Pediatric Imaging (Society for Pediatric Radiology) www.imagegently.org 23 Christopher Clement CHP Scientific Secretary International Commission on Radiological Protection PO Box 1046, Station B 280 Slater Street Ottawa, Ontario K1P 5S9 CANADA [email protected] www.icrp.org 24