Transcript PROGRESS TOWARDS NEW RECOMMENDATIONS

NKS TODAY AND TOMORROW
20 - 21 MARCH, ROSKILDE, DENMARK
RADIOLOGICAL PROTECTION
AT THE START OF THE 21ST
CENTURY:
A PROGRESS REPORT
Roger H Clarke, Chairman, ICRP
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THE FIRST PHASE
1895 - 1955
Protection was concerned with keeping
INDIVIDUAL WORKERS below the
THRESHOLDS for deterministic effects
No SOCIETAL concerns, indeed low doses
deemed beneficial and consumer
products abounded
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18902
THE MIDDLE PHASE
1955 - 1990
UTILITARIAN* ethics applied classical CostBenefit Analysis to address the question ‘How much does it cost and how many lives are
saved?’
The use of Collective Dose emphasised the
protection of SOCIETY and the inability to take
account of individual risk
*‘The doctrine that the greatest good of the greatest number should be the
guiding principle’ - Oxford English Dictionary
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1990 RECOMMENDATIONS ON
OPTIMISATION
‘This procedure should be constrained by
restrictions on the doses to individuals
(Dose Constraints),….., so as to limit the
inequity likely to result from the inherent
economic and social judgements.’
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CURRENT PHASE
1990 -
Recommendations since 1990 are in terms of
- firstly restrictions on individual dose
- then a requirement to optimise
A shift from UTILITARIAN values, so as to
include the recognition of individual rights by
using EGALITARIAN* ethics, an equity-based
system
* ‘Holding the principle of equal treatment for all persons’
- Oxford English Dictionary
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MAIN COMMISSION 2001-5
FRED METTLER
ROGER COX
LARS-ERIK HOLM
BERT WINKLER
ABEL GONZALEZ
RUDOLF ALEXAKHIN
YASUHITO SASAKI
JOHN BOICE
GRETA DICUS
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CHRISTIAN STREFFER
ANNIE SUGIER
PAN ZI QIANG
ROGER CLARKE
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THE OBJECTIVES AND SCOPE
OF THE RECOMMENDATIONS
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RISKS AT LOW DOSES AND
LOW DOSE RATES
-is there a threshold below which repair is
totally effective?
-are low doses more dangerous than we
currently assume?
Epidemiology alone cannot answer these
questions, so support is needed from
molecular studies
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THE ‘LNT’ HYPOTHESIS
above the prevalent background dose, an increment in dose
results in a proportional increment of risk
Probability of
stochastic effects, p
D
Background
incidence
p
5% / Sv
In this zone
the
relationship
is irrelevant
Background dose
D
D
Annual dose, D
average 2. 4 mSv
high
10 mSv
LO UI SV ILLE
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JUSTIFICATION
The practice leading to an exposure must
produce an overall benefit
It is a policy matter for decision makers,
-with radiological protection issues being a
minor input
For medical doctors, it is a matter both of the
generic procedure and then the individual
referral
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PRINCIPLES OF PROTECTION
for generically justified medical procedures
Justify the examination
individual-based criterion
Optimisation
Reference Levels as indicators of
good practice
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PRINCIPLES OF PROTECTION
For a justified practice or for an environmental
source
Protective Action Levels
basic levels of health protection for the
individual
Optimisation
the optimum level of health protection for a
given source
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PROTECTIVE ACTION LEVELS
PEOPLE
10 x

AVERAGE NATURAL BACKGROUND

DISCHARGES
0.1
EXCLUSION
0.01 x
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x
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OPTIMISATION OF
PROTECTION
The ‘stakeholder’ process of involving
most affected individuals is an
important approach
-EMPOWER THE WORKFORCE
-ENGAGE THE PUBLIC(S)
-Leading to the
optimum level of health protection
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RECOMMENDATIONS FOR THE
START OF THE 21st
CENTURY(i)
Develop the System of Protection
- describe the Ethical Basis
Define doses of interest for risk
- few mSv/a
Justification
- for practices,
- medical exposures to be separate
Protective Action Levels
- based on natural background
Optimisation
- replace differential equations with
common sense
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RECOMMENDATIONS FOR THE
START OF THE 21st
CENTURY(ii)
Definition of an individual
- revisit critical group
Stakeholder involvement
- how is this to be achieved
Natural radiation exposures
- philosophy as for radon?
wR and wT
- values for Effective Dose
Protection of the Environment
- policy needed
Regulatory guidance
- not prescriptive, but flexible
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OVERALL CONCLUSIONS
Before the 1950s
1960s to 1990s
Currently
- protect workers
- Utilitarianism and cba
- shift to Egalitarianism
PROTECTION AT THE START OF THE 21ST
CENTURY
Use the existence of natural background to
set PROTECTIVE ACTION LEVELS and
simplify, engage, explain
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