Transcript Title Slide
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
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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
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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
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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
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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)
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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
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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)
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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
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INTERNATIONAL COMMISSION ON RADIOLOGICAL PROTECTION
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INTERNATIONAL COMMISSION ON RADIOLOGICAL PROTECTION
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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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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
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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
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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
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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
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Alliance for Radiation Safety in Pediatric Imaging
(Society for Pediatric Radiology)
www.imagegently.org
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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
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