The ICRP System of ProtectionApplied to Medical Exposures
Results from UNSCEAR & ICRP Recommendations
South Africa -- 2009 April 15-17
Chris ClementICRP Scientific Secretary
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Overview
Why is radiological protection important in medical exposures?
The ICRP system of radiological protection in medicine
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Why is radiological protection in medical exposures important?
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Medical ExposuresThe highest source of artificial exposure, by
far
Average and collective doses increasing rapidly, particularly due to increasing use of CT
Source Global Average Dose(mSv per year)
Occupational 0.005
Atmospheric Nuclear Testing
0.005
Chernobyl Accident 0.005
Medical Diagnosis 0.6From UNSCEAR
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US NCRP Report 160, Radiation Exposure to the US Population
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US NCRP Report 160, Radiation Exposure to the US Population
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Medical Overexposures
Brain damage from radiotherapy overexposure
Whole body of baby exposed instead of chest only
18 months after cardiac catheteri-sation and stent placement
Overheated X-ray tube stopped cardiac procedure
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The ICRP system of radiological protection in medicine
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System of Protection in MedicineP 103: the complete system of protectionP 105: Radiological Protection in
Medicine (replaces P 73)
P 80: Radiation Dose to Patients from Radiopharmaceuticals
P 84: Pregnancy and Medical RadiationP 85: Avoidance of Radiation Injuries from
Medical Interventional ProceduresP 86: Prevention of accidental exposures to
patients undergoing radiation therapy
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System of Protection in MedicineP 87: Managing Patient Dose in Computed
TomographySG 2: Radiation and your patient: A guide for
medical practitionersP 93: Managing patient dose in digital radiologyP 97: Prevention of high-dose-rate brachytherapy
accidentsP 98: Radiation safety aspects of brachytherapy
for prostate cancer using permanently implanted sources
P 102: Managing Patient Dose in Multi-Detector Computed Tomography (MDCT)
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System of Protection in MedicineP 106: Radiation Dose to Patients from
Radiopharmaceuticals
and in the works:Minimising unintended exposure in radiation
therapy from new technologiesEvaluation and management of secondary
cancer risk in radiation therapy Protecting Children in Paediatric Radiology
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System of Protection in Medicine
JustificationBenefit and most of the risk apply to the patient
OptimizationALARA in medicine is management of the
radiation dose to the patient commensurate with the medical purpose
Diagnostic reference levels (not constraints)
Dose LimitationDoes not apply to medical exposures (of patients)
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Three Levels of Justification1. 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
‘Buy Our CT, Earn $ 2,163,000 in 5 Years’
INTERNATIONAL COMMISSION ON RADIOLOGICAL PROTECTION ——————————————————————————————————————
Gift Certificates for Radiation Exposure ????
INTERNATIONAL COMMISSION ON RADIOLOGICAL PROTECTION ——————————————————————————————————————
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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...”
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Optimization Two levels of optimization:
1. The design, selection and construction of equipment and installations
2. 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
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OptimizationDoses can be too highNon-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 lowThe UK Computerised Treatment Planning accident, 1982-
19911 045 patients affected, 5-30% under-dosage492 patients had a recurrence, believed to be caused by the
under-dosage
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Diagnostic Reference LevelsDetriments and benefits are received by the
same individual, the patientDose is determined principally by medical
needsDose constraints are therefore inappropriate
Diagnostic Reference Levels help evaluate whether a patient dose is unusually high or low for a particular procedure
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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 bodiesOne size does not fit all!
DRL numerical values are advisoryImplementation of the concept may be a legal requirement
DRLs should be easily measuredESD, DAP, DLP, administered activity…
DRLs apply to groups, not to single patients
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Paediatric RadiologyPoster & Sticker
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Image GentlyAlliance for Radiation Safety in Pediatric
Imaging (Society for Pediatric Radiology)
www.imagegently.org
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Christopher Clement CHP
Scientific SecretaryInternational Commission on Radiological
ProtectionPO Box 1046, Station B280 Slater StreetOttawa, Ontario K1P 5S9CANADA
www.icrp.org