1 Radiation Protection 1. Epistemology of Radiation 2. International Paradigms Radiation Protection 1. Epistemology of Radiation 2. International Paradigms WNU–Summer Institute 2012 Christ Church Lecture Hall, University of Oxford, UK; August 2 th , 2012 WNU–Summer Institute 2012 Christ Church Lecture Hall, University of Oxford, UK; August 2 th , 2012 Abel J. González Vice-President of the International Commission on Radiological Protection (ICRP) Representative to the United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR) Member of the Commission of Safety Standards of the IAEA Autoridad Regulatoria Nuclear; Av. del Libertador 8250; (C1429BNP) Ciudad de Buenos Aires, Argentina +54 11 6323 1758; (official) [email protected]; (private) [email protected]Abel J. González Vice Vice - - President of the International Commission on Radiological Protec President of the International Commission on Radiological Protec tion (ICRP) tion (ICRP) Representative to the United Nations Scientific Committee on th Representative to the United Nations Scientific Committee on th e Effects of Atomic Radiation (UNSCEAR) e Effects of Atomic Radiation (UNSCEAR) Member of the Commission of Safety Standards of the IAEA Member of the Commission of Safety Standards of the IAEA Autoridad Autoridad Regulatoria Regulatoria Nuclear Nuclear ; ; Av. del Libertador 8250; ( Av. del Libertador 8250; ( C1429BNP) Ciudad de Buenos Aires C1429BNP) Ciudad de Buenos Aires , , Argentina Argentina +54 11 6323 1758; +54 11 6323 1758; (official) (official) [email protected]; [email protected]; (private) [email protected](private) [email protected]
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1
Radiation Protection1. Epistemology of Radiation
2. International Paradigms
Radiation Protection1. Epistemology of Radiation
2. International Paradigms
WNU–Summer Institute 2012Christ Church Lecture Hall, University of Oxford, UK; August 2th, 2012
WNU–Summer Institute 2012Christ Church Lecture Hall, University of Oxford, UK; August 2th, 2012
Abel J. GonzálezVice-President of the International Commission on Radiological Protection (ICRP)
Representative to the United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR)Member of the Commission of Safety Standards of the IAEA
Autoridad Regulatoria Nuclear; Av. del Libertador 8250; (C1429BNP) Ciudad de Buenos Aires, Argentina+54 11 6323 1758; (official) [email protected]; (private) [email protected]
Abel J. GonzálezViceVice--President of the International Commission on Radiological ProtecPresident of the International Commission on Radiological Protection (ICRP) tion (ICRP)
Representative to the United Nations Scientific Committee on thRepresentative to the United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR)e Effects of Atomic Radiation (UNSCEAR)Member of the Commission of Safety Standards of the IAEAMember of the Commission of Safety Standards of the IAEA
Autoridad Autoridad RegulatoriaRegulatoria NuclearNuclear; ; Av. del Libertador 8250; (Av. del Libertador 8250; (C1429BNP) Ciudad de Buenos AiresC1429BNP) Ciudad de Buenos Aires, , ArgentinaArgentina+54 11 6323 1758; +54 11 6323 1758; (official)(official) [email protected]; [email protected]; (private) [email protected](private) [email protected]
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ContentContentFIRST PARTEpistemology:
Radiation Science and its Limitations Quantification Levels Effects
SECOND PARTProtection Paradigm
The International Radiation Protection System The International Organizations Radiation Protection Recommendations Global Regime
FIRST PARTEpistemology:
Radiation Science and its Limitations Quantification Levels Effects
SECOND PARTProtection Paradigm
The International Radiation Protection System The International Organizations Radiation Protection Recommendations Global Regime
Radiation Health Effects(Method, validity and scope of the scientific knowledge
on the detrimental effects of radiation exposure)
(3)Recent Developments on the epistemology of
Radiation Health Effects(Method, validity and scope of the scientific knowledge
on the detrimental effects of radiation exposure)
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Chromosomes
DNA
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0.2 meters!
2 nanometers
1400nanometers
Chromosomes
are a
condensed
packing of
DNA
Chromosomes
are a
condensed
packing of
DNA
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The The EnciclopedyEnciclopedy of Lifeof LifeBases Bases LettersLetters
CodonsCodons Words Words
IntronsIntrons Interruptions Interruptions
ExonsExons ParagraphsParagraphs
Genes Genes ChaptersChapters
Chromosomes Chromosomes VolumesVolumes
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Radiation harm to DNA
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Mutation!Mutation!
Many other
mutations occur due
to DNA miscopying,
thermal agitation, etc.
Usually they can be
correctly repaired by
copying the DNA
template.
Many other
mutations occur due
to DNA miscopying,
thermal agitation, etc.
Usually they can be
correctly repaired by
copying the DNA
template.
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What is the
problem then?:
the chromosome is
a very complex
packing of DNA
What is the
problem then?:
the chromosome is
a very complex
packing of DNA
nucleosomesnucleosomesnucleosomes
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10 nm
0.5 0.5 MevMev
2nm
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Chromosomes deletions
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Chromosomes Translocations
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Chromosomal aberrations are easily identifiable in the microscope
Chromosomal aberrations are easily identifiable in the microscope26 July, 2012
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radiation hits a cell nucleus!
radiation hits a cell nucleus!
No changeNo change
DNA mutationDNA mutation
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Probability of mutationProbability of mutation
DoseDose
p = a D + b D2p = a D + b D2
p = a D p = a D
pD (a D + b D2) e-cDpD (a D + b D2) e-cD
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DNA mutation pD a D
DNA mutation pD a D 3)Cell survives
but mutated
Stochasticeffects
1) Mutation repaired
Deterministic Effects (>~1Sv)
No effects
2) Cell dies
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Mutation repaired
Viable Cell
First possible outcome:mutation is repaired
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Unviable Cell
Second possible outcome:cell killing (apoptosis)
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Cell killingat around 1000mSv deterministic effects:burns, organ failure,
death!
Acute dose
Probability
> ~1000 mSv
100%
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Radiation accidents involving masive cell killing are rare
Since 1944 there were around 400 accidents
worldwide.
Approximately 3000 persons were injured,
with 120 fatalities (including 28 Chernobyl
victims).
Since 1944 there were around 400 accidents
worldwide.
Approximately 3000 persons were injured,
with 120 fatalities (including 28 Chernobyl
victims).
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57
58
59
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Cell survives but mutated
Altered process
Third possible outcome:viable but mutated cell
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Normal process
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Altered process
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Cell survives but mutated
Stochastic effects
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Stochastic effects
Cancer
Hereditable
Antenatal
Cancer
Hereditable
Antenatal
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CancerCancer
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6666
Prevalent opinion onradiation-induced cancer
Radiation Radiation
mutates DNAmutates DNA
Failure to Failure to
repair DNA repair DNA
Viable cell withViable cell with
carcinogenescarcinogenes
TumourTumour
promotionpromotion
Malignant Malignant
conversion conversion
Metastasis of Metastasis of
malignancymalignancy
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INMUNE SYSTEMINMUNE SYSTEM
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Estimates of the Risk of Cancer due to
Radiation Exposure
Estimates of the Risk of Cancer due to
Radiation Exposure
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Radioepidemiology
(Epidemia (Gk): prevalence of disease)(Epidemia (Gk): prevalence of disease)
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Control group“N” people“C” cancers“n” probability of ‘natural’ cancer
Control group““NN”” peoplepeople““CC”” cancerscancers““nn”” probability of probability of ‘‘naturalnatural’’ cancercancer
Exposed group“N” people“E” cancers“n” probability of ‘natural’cancer‘pD’ probability of ‘radiation’ cancer
Exposed group““NN”” peoplepeople““EE”” cancerscancers““nn”” probability of probability of ‘‘naturalnatural’’cancercancer‘‘ppDD’’ probability of probability of ‘‘radiationradiation’’ cancercancer
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E= n N
+ pd D N
Numberof
cancersin
exposedgroup
C=n N
Numberof
cancersin
controlgroup
C=n N
Numberof
cancersin
controlgroup
E-C
Difficult to assess!
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UNSCEAR has reviewed many many
epidemiological data on effects of radiation in
exposed populations
UNSCEAR has reviewed many many
epidemiological data on effects of radiation in
exposed populations
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The radium dial painters,…
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…the early x-rays doctors and patients……the early x-rays doctors and patients…
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..the Mayak cohort of workers…
MAYAK
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..the survivors of Hiroshima y Nagasaki....the survivors of Hiroshima y Nagasaki..
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…all these victims of radiation exposure have
unwillingly contributed to the
UNSCEAR’s epidemiological assessments.
…all these victims of radiation exposure have
unwillingly contributed to the
UNSCEAR’s epidemiological assessments.
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Slide 6
Cohort of Hiroshima & Nagasaki(LIFE SPAN STUDY, LSS)
Mt.HijiMt.Hiji
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Solid Cancer Mortality47 years of follow-up (1950-1997)
Exposed population: 9,335 (10,127) cancer deaths
Reference population: 8,895 (9,648) cancer deaths
~440 (479) cancers attributable to radiation (5%)
Exposed population: 9,335 (10,127) cancer deaths
Reference population: 8,895 (9,648) cancer deaths
~440 (479) cancers attributable to radiation (5%)
Preston et al, Radiat Res 160:381-407, 2003(updated figures)Preston et al, Radiat Res 160:381-407, 2003(updated figures)
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Lifetime cancer mortality risk (after 1000 mSv acute dose)
~ 0.6-1.0%. for leukæmia
and
~4.3–7.2% for all solid cancers combined, (lower for men than for women)
Lifetime cancer mortality risk (after 1000 mSv acute dose)
~ 0.6-1.0%. for leukæmia
and
~4.3–7.2% for all solid cancers combined, (lower for men than for women)
Lifetime cancer risk estimates for those exposed as children might be a factor of 2 to 3 times higher than the estimates for a population exposed at all ages.
Lifetime cancer risk estimates for those exposed as children might be a factor of 2 to 3 times higher than the estimates for a population exposed at all ages.
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UNSCEAR Estimates of NOMINAL Cancer Risk
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Hereditable EffectsHereditable Effects
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Prevalent opinion on the induction of hereditable effects from radiation exposure
Radiation Radiation
Mutes the DNA Mutes the DNA
of a Germinal of a Germinal
CellCell
Failure to Failure to
RepairRepair
Viable Sperm Viable Sperm
or Ovum or Ovum
Containing Containing
Defective GenesDefective Genes
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The risk is so low that the estimation has to be based on animal studies
The risk is so low that the estimation has to be based on animal studies
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Hereditable Effects
Total risk to first generation following parental exposure:
~ 0.2% per Sv
>1/10 the risk of fatal carcinogenesis
constitutes 0.5% of baseline
Total risk to first generation following parental exposure:
~ 0.2% per Sv
>1/10 the risk of fatal carcinogenesis
constitutes 0.5% of baseline
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Antenatal EffectsAntenatal Effects
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1000mSv1000mSv
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= IQ= IQ
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Shift in the IQ curve:30 IQ units per 1000 mSv incurred during the 8-15 weeks
1000mSv1000mSv
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= IQ= IQ
89
Latest newsLatest news
91
93
Summary
of the scientific knowledge
Summary
of the scientific knowledge
94
Dose (Sv)
Likelihoodof health effects
100%(certainty)
~0,1
Approx. lower bound
of pathological knowledge
~ 5%(UNSCEAR estimate)
~1 ~10
Tissue reactionsClinical diagnosis
(individual pathology)
Approx. lower bound of epidemiological
knowledge
Cytogenetic exposure indicators
radiation
syndromes
and death
~ 10%
~ 1%
General radiobiological information
Increase incidence of malignanciesStatistical estimates (epidemiology of populations)
The time scale of the phenomena limits knowledge.The time scale of the phenomena limits knowledge.26 July, 2012
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New UNSCEAR’s assessments
Epidemiological evaluation of cardiovascular disease
Non-targeted and delayed effects of radiation exposure
Effects of ionizing radiation on the immune system
Epidemiological evaluation of cardiovascular disease
Non-targeted and delayed effects of radiation exposure
Effects of ionizing radiation on the immune system
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Cardiovascular diseasesCardiovascular diseases
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Chernobyl workers,
atomic bomb survivors, and
radiotherapy patients …
… seem to suffer a higher risk of
cardiovascular diseases.26 July, 2012
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‘Non-targeted’and
delayed effectsof radiation exposure
‘Non-targeted’and
delayed effectsof radiation exposure
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Adaptive Response
+
Mutation
Mutations
Mutations
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Adaptive responseconditioningconditioning
dosedose responseresponse
challengingchallengingdosedose
responseresponse
conditioningconditioningdosedose
challengingchallengingdosedose
responseresponse++
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The role of apoptosis(cell killing by mutations)
If at low doses, apoptosis >> carcinogenesis...
..then.. hormesis!
If at low doses, If at low doses, apoptosis >> carcinogenesis......
..then.. ..then.. hormesishormesis!!
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ApoptosisApoptosis
Dose rateDose rate
Mutation RateMutation Rate
ApoptosisApoptosis
CarcinogenesisCarcinogenesis
hormesishormesis
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Genomic instability …Genomic instability …
… or … increased rate of acquisition of
alterations in the genome.
… or … increased rate of acquisition of
alterations in the genome.
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Basic paradigms of radiobiology
Effects occur in cells whosenucleus crossed by radiation
Damage fixed in DNA of irradiated cell, if not lethal, transmitted to descendant
MicronucleusMicronucleus
Mitotic failure: aneuploid
Mitotic failure: aneuploid
MutationMutation Chromosomalaberration
Chromosomalaberration
Cellular death
Cellular death
Challenge to the paradigm
Genomic instabilityGenomic instability
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Bystander effects
The so-called “bystander” effect is the ability of irradiated
cells to convey damage to neighbouring cells
not directly irradiated.
The so-called “bystander” effect is the ability of irradiated
cells to convey damage to neighbouring cells
not directly irradiated.
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“Bystander” effect
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Signals via intercellular unions(Azamm 2001)
Signals via intercellular unions(Azamm 2001)
Signals via medium/plasmaSignals via medium/plasma
ROSNitric oxideCytokinesTGF
(Lehnert 1997)
ROSNitric oxideCytokinesTGF
(Lehnert 1997)
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Clastogenic plasma factors
There is a large body of evidence that blood plasma from
irradiated animals and humans can contain so-called
“clastogenic plasma factors” capable of inducing
chromosomal damage in unexposed cells.
There is a large body of evidence that blood plasma from
irradiated animals and humans can contain so-called
“clastogenic plasma factors” capable of inducing
chromosomal damage in unexposed cells.
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Abscopal effects
An abscopal effect is said to occur if there is a significant
response in a tissue that is physically separate from the
region of the body exposed to radiation.
An abscopal effect is said to occur if there is a significant
response in a tissue that is physically separate from the
region of the body exposed to radiation.
Human & Experimental Toxicology, Volume 23, Issue 2, 1 February 2004, ArnoldHuman & Experimental Toxicology, Volume 23, Issue 2, 1 February 2004, Arnold
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Irradiation ofan organ
Irradiation ofan organ
Effects in another organ
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Effects of ionizing radiation on the
immune system
Effects of ionizing radiation on the
immune system
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Infections
Cancer
Immune
system
Does radiation exposure affect the immune system?
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129
SECOND PART
Protection Paradigm:
The International Radiation Protection System
SECOND PART
Protection Paradigm:
The International Radiation Protection System
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(1)
The International Organizations
(1)
The International Organizations
WNU-Summer Institute
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Epistemology of radiationMethod, validity and scope of the scientific
knowledge on radiation
Radiation Protection ParadigmConceptual model for keeping people protected
Global Radiation Safety RegimeEstablishing international safety standards and
providing for their global application
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UNSCEARUNSCEAR
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The United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR)
Established by the UN General Assembly in 1955 Assess levels & effects of ionizing radiation Reports findings to Assembly Scientists from 21 UN Member States Other States provide relevant data Holds annual sessions in Vienna UNEP arranges secretariat and provides support
Established by the UN General Assembly in 1955 Assess levels & effects of ionizing radiation Reports findings to Assembly Scientists from 21 UN Member States Other States provide relevant data Holds annual sessions in Vienna UNEP arranges secretariat and provides support
134134
Member States on UNSCEAR
Argentina Brazil Mexico Peru Australia China India Indonesia Japan Korea Pakistan Canada USA
Argentina Brazil Mexico Peru Australia China India Indonesia Japan Korea Pakistan Canada USA
Egypt Sudan Belgium Belarus Finland France Germany Poland Russia Slovakia Spain Sweden UK Ukraine
Egypt Sudan Belgium Belarus Finland France Germany Poland Russia Slovakia Spain Sweden UK Ukraine
135
WNU-Summer InstituteWNU-Summer Institute 135135
The latest UNSCEAR reportsThe latest UNSCEAR reports
Norway 17.6.1961 Paraguay 10.7.1967 Poland 23.12.1964 Portugal 17.3.1994 Russian Fed. 22.9.1967 Slovakia 1.1.1993 Spain 17.7.1962 Sri Lanka 18.6.1986 Sweden 12.4.1961 Switzerland 29.5.1963 Syrian A. R. 15.1.1964 Tajikistan 26.11.1993 Turkey 15.11.1968 Ukraine 19.6.1968 U.K. 9.3.1962 Uruguay 22.9.1992
Norway 17.6.1961 Paraguay 10.7.1967 Poland 23.12.1964 Portugal 17.3.1994 Russian Fed. 22.9.1967 Slovakia 1.1.1993 Spain 17.7.1962 Sri Lanka 18.6.1986 Sweden 12.4.1961 Switzerland 29.5.1963 Syrian A. R. 15.1.1964 Tajikistan 26.11.1993 Turkey 15.11.1968 Ukraine 19.6.1968 U.K. 9.3.1962 Uruguay 22.9.1992
149
(2)The International Radiation
Protection Recommendations
The conceptual model for keeping people safe from radiation exposure
(2)The International Radiation
Protection Recommendations
The conceptual model for keeping people safe from radiation exposure
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150
In paradigm choice there is no standard higher
than the assent of the relevant community
Thomas S. Kuhn, The Structure of Scientific Revolutions, p. 93 (1960).
In paradigm choice there is no standard higher
than the assent of the relevant community
Thomas S. Kuhn, The Structure of Scientific Revolutions, p. 93 (1960).
151
Totalbackground incidence of effects
Background annual dose
(average 2.4, typical 10 mSv y-1)
Postulated likelihood of health effects
Dose
Radiation-unrelatedbackground
incidence
Presumedradiation-related
background incidence
Nominal incrementallikelihoodof health effects
Incremental dose
0.005%/mSv0.005%/mSv
152
ICRP had to introduce the concept of
‘detriment-adjusted’
‘nominal’ risk coefficients
ICRP had to introduce the concept of
‘detriment-adjusted’
‘nominal’ risk coefficients
153
Detriment-adjusted Nominal Risk Coefficients
Risk Coefficient: A numeral, expressed in % Sv-1, which –multiplied by dose– quantifies the plausibility of harm.
Nominal: The stated numeral does not necessarily correspond to its real value: it relates to hypothetical (no real) people who are averaged over age and sex.
Detriment-adjusted: The numeral is multidimensional, expressing plausible expectation of harm, and includinginter alia the weighted plausibility of fatal and non-fatal harm, and life-lost should the harm actually occur.
Risk Coefficient: A numeral, expressed in % Sv-1, which –multiplied by dose– quantifies the plausibility of harm.
Nominal: The stated numeral does not necessarily correspond to its real value: it relates to hypothetical (no real) people who are averaged over age and sex.
Detriment-adjusted: The numeral is multidimensional, expressing plausible expectation of harm, and includinginter alia the weighted plausibility of fatal and non-fatal harm, and life-lost should the harm actually occur.
3 systemshomogeneous, coherent and consistent….but distinct
Patients
Occupational
Public
Patients
Occupational
Public
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Source constraint
Doses to be constrained arethose committed in a year
rather than those incurred in a year!
Doses to be constrained arethose committed in a year
rather than those incurred in a year!
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Patients(The exposure is voluntary, beneficial for the individual exposed and measurable)(The exposure is voluntary, beneficial for the individual exposed and measurable)
• Radiodiagnosis
• Radiotherapy
• Radiodiagnosis
• Radiotherapy
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Doses in mSvDoses in mSv
100 100
~~ 10 10
~~ 11
TYPICALLY HIGHTYPICALLY HIGH
TYPICALTYPICAL
MINIMALMINIMAL
HIGHHIGHFluoroscopFluoroscopyy
Vertebral Vertebral
TTooraxrax
Guidance for the Guidance for the protection of protection of patients in patients in
radioradio--diagnosisdiagnosis
190
TRAINING..!!TRAINING..!!
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Occupational exposure:
ALL exposure of workers incurred in the course of
their work.
Occupational exposure:
ALL exposure of exposure of workers incurred workers incurred in the course of in the course of
their work.their work.
Workers(voluntary and individually monitored exposure)
Monitored workerMonitored worker
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Maximum Maximum (except life saving)(except life saving)
mSv in a year
1000
500
100
50
20
OccupationalDose
Restrictions
OccupationalDose
Restrictions
OptimizationOptimizationofof
ProtectionProtection
Annual dose limitAnnual dose limit
Average dose limitAverage dose limit
EEvery effort novery effort nott to to exceedexceed itit
RREESSCCUUEE
All reasonable All reasonable efforteffortssnonot to t to exceedexceed itit
NNOORRMMAALL
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The female worker:
protecting the
unborn and
the infant
The female worker:
protecting the
unborn and
the infantWNU-Summer Institute
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Members of the Public(involuntary no-individually monitored exposure)
19726 July, 2012 197
Members of the Public(involuntary no-individually monitored exposure)
Planned exposure situations
(Practices) restrict
the expectedadditional doses
belowindividual dose limitsand source constraints
Planned exposure situations
(Practices) restrict
the expectedadditional doses
belowindividual dose limitsand source constraints
Existing & emergency exposure situations
(Interventions) reducethe extant
avertable dosesbelow
reference levels
Existing & emergency exposure situations
(Interventions) reducethe extant
avertable dosesbelow
reference levels
(planned)‘Practices’
(planned)‘Practices’
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Naturalbackground
radiation
ExpectedExpectedadditional additional
dose dose
Activity introducedActivity introduced
(planned) ‘Practices’
RestrictionsRestrictions: dose limits and constraints: dose limits and constraints
20026 July, 2012 200Wastes
Hospitals
IndustryTransport
Mining
Nuclear power
Industry
Dose limit
20126 July, 2012 201
Source constraint
WNU-Summer Institute
Doses to be constrained arethose committed in a year
rather than those incurred in a year!
Doses to be constrained arethose committed in a year
rather than those incurred in a year!
202
mSv in a year
1
0.01
1
0.01
Restrictions on the dose
attributable to practices
(additional annual dose)
Restrictions on the dose
attributable to practices
(additional annual dose)
Optimization of protection
Optimization of protection
Source constraintSource constraint
Regulatory limitRegulatory limit
Regulatory exemptionRegulatory exemptionWNU-Summer Institute
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‘Interventions’(in existing and emergency situations)
‘Interventions’(in existing and emergency situations)
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AvertableDose
Howmuch?
AvertableDose
HowHowmuch?much?
Referencelevel
Extant Dose
Should Should it be it be
reduced?reduced?
‘Interventions’(in existing and emergency situations)
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INTERVENTIONINTERVENTIONALMOST ALWAYS ALMOST ALWAYS
JUSTIFIABLE JUSTIFIABLE
mSv in a year100
10
1
CRITERIA FOR INTERVENING (Extant Annual Dose)
CRITERIA FOR INTERVENING (Extant Annual Dose)
INTERVENTIONINTERVENTIONIS NOT LIKELY TO BE IS NOT LIKELY TO BE
JUSTIFIABLEJUSTIFIABLE
INTERVENTIONINTERVENTIONMAY BEMAY BE
JUSTIFIABLEJUSTIFIABLE
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Simplified summary of dose
restrictionsand reference
levels(in mSv in a year)
Simplified summary of dose
restrictionsand reference
levels(in mSv in a year)
NO INDIVIDUAL/SOCIETAL BENEFIT ABOVE THIS Emergency workers Emergency workers Evacuation/relocation in emergenciesEvacuation/relocation in emergencies High levels of existing controllable exposuresHigh levels of existing controllable exposures Information, training, monitoringInformation, training, monitoring
DIRECT OR INDIRECT BENEFIT TO THE INDIVIDUALOccupational exposureSheltering, stable iodine, in emergenciesExisting exposures such as radon Comforters and carers to patients Information, training, monitoring or assessment
SOCIETAL, BUT NO INDIVIDUAL DIRECT BENEFITNormal situations No information or training, No individual dose assessment
Exclusion, exemption, clearance
100100
2020
11
0.010.01
207
The use of a reference
level in an existing
exposure situation and
the evolution of the
distribution of
individual doses with
time as a result of the
optimization process
The use of a reference
level in an existing
exposure situation and
the evolution of the
distribution of
individual doses with
time as a result of the
optimization process
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In paradigm choice there is no standard higher than the assent of the relevant community
DecisionDecision--aiding Processaiding Processbased on radiation protection consideration
DecisionDecision--making Processmaking Process
involving relevant ‘stakeholders’
searching for their informed consent
209
(4)
The International
Regime
(4)
The International
Regime
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The IAEA is the only organ within the UN system with specific statutory responsibilities
on radiation protection and safety
The IAEA is the only organ within the UN system with specific statutory responsibilities
on radiation protection and safetyWNU-Summer Institute
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“For their efforts
[i] to prevent nuclear energy from being used for military purposes and
[ii] to ensure that nuclear energy for peaceful purposes is
used in the safest possible way“
“For their efforts
[i] to prevent nuclear energy from being used for military purposes and
[ii] to ensure that nuclear energy for peaceful purposes is
used in the safest possible way“
The Nobel Peace Prize2005
TheThe NobelNobel PeacePeace PrizePrize20052005
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to establishstandards
to establishstandards
to provide for their applicationto provide for
their application
to service international conventionsto service international conventions
IAEAstatutory safety functions
IAEAstatutory safety functions
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Legally Binding
ConventionsLegally Binding
Conventions
214
Convention on Early Notification of a Nuclear Accident
215
Convention on Assistance in the Case of a Nuclear Accident or Radiological Emergency
216
Convention on Nuclear Safety
217
Joint Convention on the Safety of Spent Fuel Management and on the
Safety of Radioactive Waste Management
218
Convention on Physical Protection of Nuclear Material
21926 July, 2012 219
International
Radiation Safety
Standards
International
Radiation Safety
Standards
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Commissionon Safety Standards
(CSS)
Nuclear Safety StandardsCommittee(NUSSC)
Radiation Safety StandardsCommittee(RASSC)
Waste Safety StandardsCommittee(WASSC)
Transport Safety StandardsCommittee(TRANSSC)
Expert Groups Expert Groups Expert Groups Expert Groups
Safety Principles 1: Responsibility for safety 2: Role of government 3: Leadership and management for safety 4: Justification of facilities and activities 5: Optimization of protection 6: Limitation of risks to individuals 7: Protection of present and future generations 8: Prevention of accidents 9: Emergency preparedness and response 10: Protective actions to reduce existing or
unregulated radiation risks
1: Responsibility for safety 2: Role of government 3: Leadership and management for safety 4: Justification of facilities and activities 5: Optimization of protection 6: Limitation of risks to individuals 7: Protection of present and future generations 8: Prevention of accidents 9: Emergency preparedness and response 10: Protective actions to reduce existing or
unregulated radiation risks
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22826 July, 2012 228
rendering APPRAISAL SERVICES
coordinating RESEARCH & DEVELOPMENT
fostering INFORMATION EXCHANGE
providing TECHNICAL ASSISTANCE
Provisionsfor the
application of the
standards:IAEA
mechanisms
promoting EDUCATION & TRAINING
22926 July, 2012 229
Example on how the system for
establishing standards works:Example on how the system for
establishing standards works:
The Regulations for Safe TransportThe Regulations for Safe Transport
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to Geneva
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233
234
235
236
237
238
Take away points
1. Additional doses to members of the public should not exceed 1 millisievert in a year
2. Total doses to workers should not exceed 20 millisievert in a year, except for emergency workers () and pregnant workers ()
3. Existing doses to members of the public of several tens of millisieverts, e.g. following an accident, will justify intervention with special protective measures, but if the doses are around 1 millisievert intervention may not be justifiable.
1.1. Additional doses to members of the public Additional doses to members of the public should not exceed should not exceed 1 millisievert in a year
2.2. Total doses to workers should not exceed Total doses to workers should not exceed 20 millisievert in a year, except for , except for emergency workers (emergency workers () and pregnant workers () and pregnant workers ())
3.3. Existing doses to members of the public of Existing doses to members of the public of several tens of millisieverts, e.g. following an , e.g. following an accident, will justify intervention with special accident, will justify intervention with special protective measures, but if the doses are around protective measures, but if the doses are around 1 1 millisievertmillisievert intervention may not be justifiable.intervention may not be justifiable.
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Take away points
1. There is a growing international safety regime
2. Obey the international conventions
3. Comply with the international requirements
4. Follow the international guides
5. Use the IAEA application mechanisms
1.1. There is a growing international safety regimeThere is a growing international safety regime
2.2. Obey the international conventionsObey the international conventions
3.3. Comply with the international requirementsComply with the international requirements
4.4. Follow the international guidesFollow the international guides
5.5. Use the IAEA application mechanismsUse the IAEA application mechanisms
Policy Implications on effects at low doses :The effects are
probable and, therefore,plausible
but, they are notprovable!
Policy Implications Policy Implications on effects at low doses ::The effects areThe effects are
probable and, therefore,plausible
but, they are notprovable!
26 July, 2012 244S
Low-dose effects cannot be attributed
to radiation exposure!
Low-dose effects cannot be attributed
to radiation exposure!
245WNU, , 2008
Dose (mSv)
Likelihood of Health Effect
Certainty(100%)
epidemiology pathology
Limit of epidemiology
Limit of epidemiology
Limit ofpathologyLimit of
pathology
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246WNU, , 2008
Dose (mSv)
Certainty(100%)
Epidemiology Pathology
PlausiblePlausible Collective estimate
Collective estimate
Individual diagnosisIndividual diagnosis
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Likelihood of Health Effect
247
Dose (mSv)
Certainty(100%)
Epidemiology Pathology
No attribution
No attribution
Collective attributionCollective attribution
Individual attributionIndividual attribution
26 July, 2012
Likelihood of Health Effect
248
Dealing with uncertainties
Is it plausible that there is a risk at low doses?
Dealing with uncertainties
Is it plausible that there is a risk at low doses?
PlausibilityApparently reasonable or probable,
without necessarily being so.from L. plausibilis, from plaus-, plaudere ‘applaud’.
PlausibilityApparently reasonable or probable,
without necessarily being so.from L. plausibilis, from plaus-, plaudere ‘applaud’.
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249249WNU-Summer Institute
ICRP Publication 99
Low - Dose Extrapolation
of Radiation Related
Cancer Risk
2006
ICRP Publication 99
Low - Dose Extrapolation
of Radiation Related
Cancer Risk
2006
26 July, 2012
Charles E Land; Uncertainty, lowCharles E Land; Uncertainty, low--dose extrapolation and the threshold hypothesis; dose extrapolation and the threshold hypothesis; J. J. RadiolRadiol. Prot. . Prot. 22 22 (2002) 1(2002) 1––77
250WNU-Summer Institute250
Nominal statistical uncertainty distribution for excess lifetimerisk of solid cancer mortality among atomic-bomb survivors
Confidence limits 7.5–12.5% Sv-1
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Uncertainty distribution for excess lifetime risk(taking into account extrapolation to another population)
confidence limits 1.2–8.8% Sv-1
approximately approximately loglog--normal normal
15 M a y , 2004 IR P A11: S ie vert L ecture 134
1 .0 -
0 .8 -
0 .6 -
0 .4 -
0 .2 -
‘2
‘4
‘6
‘8
‘10
‘12
‘14
R isk (% )/S v
C u m u la tivep ro b ab ility
95 % u p per lim it
5%
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1.0-
0.8-
0.6-
0.4-
0.2-
‘2
‘4
‘6
‘8
‘10
‘12
‘14
Risk (%)/Sv
Cumulativeprobability
95% upper limit
5%
Assuming a 20%
probability of threshold8.8%/Sv
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1.0-
0.8-
0.6-
0.4-
0.2-
‘2
‘4
‘6
‘8
‘10
‘12
‘14
Risk (%)/Sv
Cumulativeprobability
95% upper limit
5%
Assuming a 50%
probability of threshold
7%/Sv
8.8%/Sv
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1.0-
0.8-
0.6-
0.4-
0.2-
‘2
‘4
‘6
‘8
‘10
‘12
‘14
Risk (%)/Sv
Cumulativeprobability
95% upper limit
5%
Assuming a 80%
probability of threshold
5%/Sv
8.8%/Sv
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… Namely …
…ICRP considers that due to the
uncertainties in the radiation risk estimates,
it should presume a nominal radiation risk at low
doses and recommends to limit such nominal risk
with radiation protection measures.
…ICRP considers that due to the
uncertainties in the radiation risk estimates,uncertainties in the radiation risk estimates,
it should presume a nominal radiation risk at low
doses and recommends to limit such nominal risk
with radiation protection measures.26 July, 2012
Policy Implications:
plausibility of effects at low dosesversus
their attributability
Policy Implications:Policy Implications:
plausibility of effects at low dosesversus
their attributability
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257WNU-Summer Institute 257
Likelihood of radiation health effects
Doses Doses
Likelihood
Certainty(100%)
0.005%/mSv for cancer0.0002%/mSv for hereditable
0.005%/mSv for cancer0.0002%/mSv for hereditable
Uncertainty!Uncertainty!
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AttributabilityAttributability
Attribute: regard something as being caused by.
from L. attribut- ‘allotted’: both from attribuere, from ad- ‘to’ + tribuere
‘assign’.
Attribute: regard something as being caused by.
from L. attribut- ‘allotted’: both from attribuere, from ad- ‘to’ + tribuere
‘assign’.
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259259WNU-Summer Institute
Epistemological limits in radioepidemiologyEpistemological limits in radioepidemiology
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Control group“N” people“C” cancers“n” probability of ‘natural’ cancer
Control group““NN”” peoplepeople““CC”” cancerscancers““nn”” probability of probability of ‘‘naturalnatural’’ cancercancer
Exposed group“N” people“E” cancers“n” probability of ‘natural’cancer‘pD’ probability of ‘radiation’ cancer
Exposed group““NN”” peoplepeople““EE”” cancerscancers““nn”” probability of probability of ‘‘naturalnatural’’cancercancer‘‘ppDD’’ probability of probability of ‘‘radiationradiation’’ cancercancer
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E= n N
+ pd D N
Numberof
cancersin
exposedgroup
C=n N
Numberof
cancersin
controlgroup
C=n N
Numberof
cancersin
controlgroup
E-C
Difficult to detect!
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Limitation of knowledge in epidemiology
The standard deviation is
= 2 n N + pd D N If the excess cancers are to be detected with a statistical
confidence of 95%
E – C > 2
The standard deviation is
= 2 n N + pd D N If the excess cancers are to be detected with a statistical
confidence of 95%
E – C > 2
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Epidemiological limit
Operating algebraically and as n >> pd D,
N > constant / D2
which is the equation giving the number of people, N, needed for detecting excess cancers at dose D.
Operating algebraically and as n >> pd D,
N > constant / D2
which is the equation giving the number of people, N, needed for detecting excess cancers at dose D.
(Constant = 8 n / pd2)
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10 2
10 1
10-0
10-1 10 2 10 4 10 6 10 8
Dose (Dose (mSvmSv))
PeoplePeople
knowledgeknowledge
unprovableunprovable
1 1 mSvmSv10 9 p.
SOLID CANCERS
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10 2
10 1
10-0
10-1 10 2 10 4 10 6 10 8
Dose (Dose (mSvmSv))
PeoplePeople
~1 ~1 mSvmSv
HEREDITABLE EFFECTS
~10~1012 12 people!people!
knowledge(very limited)
knowledge(very limited)
unprovableunprovable
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C H E R N O B Y LC H E R N O B Y L
267
268
Radiation Doses
Average over 10 years 8 mSv
For life 13 mSv
Average over 10 years 8 mSv
For life 13 mSv
269
annual dosemSv/year
~100
~ 10
~ 2.4
~ 1
Natural Background
TYPICALLY HIGHTYPICALLY HIGH
AVERAGE AVERAGE
MINIMUM MINIMUM
VERY HIGHVERY HIGHFew peopleIn few areas
Many peopleIn many areas
Majority of peoplearound the world
Chernobyl for life Chernobyl for life
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10 2
10 1
10-0
10-1 10 2 10 4 10 6 10 8
Dose (Dose (mSvmSv))
PeoplePeople
SOLID CANCERS in Chernobyl(except thyroid cancers in children)
Chernobyl doses Chernobyl doses ~10 ~10 mSvmSv
Chernobyl residents residents in strict control areas in strict control areas
~300 000~300 000
knowledgeknowledgeunprovableunprovable
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10 2
10 1
10-0
10-1 10 2 10 4 10 6 10 8
Dose (Dose (mSvmSv))
ChildrenChildren
Thyroid Cancer
knowledge(very expanded)knowledge
(very expanded)
unprovableunprovable
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274WNU, , 274
Thyroid cancer in children in Belarus
Thyro id cancer in ch ild ren in B elarusThyro id cancer in ch ild ren in B elarusThyroid ca ncer in children in Be la rus