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

sci.sec@icrp.org

www.icrp.org