Radiation Dose Limits for Adult Subjects
Henry D. Royal, M.D.
Associate DirectorDivision of Nuclear Medicine
Mallinckrodt Institute of Radiology
Professor of RadiologyWashington University School of Medicine
St. Louis, MOFDA Meeting 11/16/04
Past and Present Experiences
IAEA International Chernobyl ProjectSeveral NAS CommitteesPresidential Advisory Committee on
Human Radiation ExperimentsImmediate Past President, SNMVeterans Advisory Committee for
Environmental HazardsBoard of Directors, NCRPUS Delegate to UNSCEAR
Overview
Current RegulationsLimitations of Current RegulationsCommunicating RisksAnswers to QuestionsOther Comments
Whole Body, Active Blood-forming Organs, Lens Of The Eye, And Gonads:
Rem
Single dose 3
Annual and total dose commitment
5
Other Organs: Rem
Single dose 5
Annual and total dose commitment
15
Limitations
Linked to Occupational ExposureWhole Body DoseNo Adjustment for AgeNo Adjustment for Life Expectancy
Linked to Occupational Exposure
Rationale UnclearSince Subjects Will Not Directly
Benefit From RDRC Studies, Risk Should be Minimal
Unfortunately, Minimal Risk is Ambiguously Defined
Whole Body Dose
Should Be Replaced By EDDose is a Surrogate for RiskDose Limits Should Be Modified To
Adjust For Age And Life Expectancy
ConsumerProducts
0
200
400
600
800
1000
1200
1400
1600
0 10 20 30 40 50 60 70 80
Leukemia
Cancers
Age
Can
cers
per
10
4 P
ers
on
-Gy
Females
BEIR V 1990
Communicating Risks
The Magnitude of a Risk Depends on Framing
Common Approach:
Radiation Increases the Risk of a Fatal Cancer by 4%-5% per Sievert (100 rems)
For a 5 Rem ED
Participation In this Research Study Will Increase Your Chances of Getting Cancer (Dying) by 2/1000
Communicating Risks
What’s Wrong With This Approach?
Very Difficult For Most People to Think in Terms of Numerical Risks
Does Not Distinguish Between Immediate Deaths and Delayed Deaths
Does Not Account for Age or Life Expectancy
Loss of Life
< 1 Gy – 2 Months
>1 Gy – 2.6 Years
60% Cancer
30% Other
10% Leukemia
Cologne et al: Lancet 2000; 356:303-07
Alc
oh
olic
Poor
Socia
l S
tatu
s Gra
de S
ch
ool D
rop
-Ou
t
Can
cer
20%
Overw
eig
ht
Hig
h
Ris
k J
ob
Orp
ah
ned
Povert
y
Sm
okin
g -
Male
Heart
D
isease
Moto
r V
eh
icle
Accid
en
ts
1,000
2,000
3,000
4,000
Cohen: Health Physics 61:317-335, 1991
5,000
6,000Loss o
f Lif
e
Exp
en
tan
cy (
Days)
Catalog of Risks
Su
icid
e
Dri
nkin
g W
ate
r
Fir
e,
Bu
rns
Alc
oh
ol
Mu
rder E
nerg
y C
on
serv
ati
on
Moto
r V
eh
icle
Accid
en
ts
Loss o
f Lif
e
Exp
en
tan
cy (
Days)
50
100
150
200
Catalog of Risks
Cohen: Health Physics 61:317-335, 1991
Air
Pollu
tion
Sm
all C
ars
AID
S
Rad
on
Pesti
cid
es
Pois
on
Natu
ral H
azard
s
Bic
ycle
s
Sp
ou
se S
mokin
g
Dro
wn
ing
Rad
iati
on
Work
er
250
300
An Alternative Approach
Variations in Background Radiation
±100 mrem X 70 Years = 7 remNot Possible to Measure the Risk Directly“…the possibility that there may be no
risks from exposures comparable to external natural background radiation can not be ruled out.”
BEIR V 1990 Page 181
Unintended Consequences
Some Populations Will Not Benefit From Medical Research
Increased Collective Dose to Obtain the Same Information
Opportunity Costs
Answers to Questions
Current Dose Limits (5 Rem Annual Dose) Are Appropriate
Should Adjust for Age and Life Expectancy So That Dose is A Better Surrogate For Risk
Top Related