A Different Approach to Evaluating Health Effects from Radiation Exposure
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V. P. Bond! , C. A. Sondhaus?, and L. E. Feinendegen>
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ABSTRACT
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Absorbed dose D is shown to be a composite variable,
the product of
the fraction of cells hit (F) and the mean “dose" (hit size) Z to the hit
Mone
cells. D is suitable for use with high level exposure (HLE) to radiation
NS,
and its resulting acute organ effects because F = 1.0,
and
approximates closely enough the mean energy density in both the cell and
ral a
(193
the organ.
However, with low-level exposure (LLE) to radiation and its
consequent probability of cancer induction from a single cell, F is <<1.0
and stochastic delivery of energy to cells results
acellular
of single hit sizes.
d
with exposure,
acrar©
at.
and
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pe
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so that only F can vary with D.
46,
none
miqul
roxide
the fraction of cells transformed, obtained with LLE,
misleading.
It does not mean that any (cell) dose, no matter how small,
on the
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diat.
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cells.
Rather,
it means
is
that an exposure of a population of the
constituent relevant cells of an organ results in a Linear increase in the
number of cells dosed, but not in cell dose.
The probability of such a
dosed cell transforming and initiating a cancer can only be greater than
Otherwise stated,
misonidazole
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the apparent proportionality between this
zero if the hit size ("dose of energy”) to the cell is large enough.
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However, because D is the
quantity and
can be lethal,
ancer
in a wide distribution
As a result the expectation value of z is constant
mean organ= and not cell dose,
32.C¢
c
so that D
if the “dose” is defined at the proper level of
biological organization, namely,
the cell and not
the organ, only a large
dose to that cell is effective.
The above precepts are utilized to develop
a drastically different approach to evaluation of the risk from LLE, that
holds promise of obviating any requirement for use in this region of the
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en nigh See
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principal components of the present system: absorbed organ dose, LET, a
standard radiation, RBE, Q, dose equivalent and rem.
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rookhaven National Laboratory
This research was supported in part by the U.S. Department of Energy
under Contract DE-ACO2-76CHO0016. Accordingly, the U.S. Government
retains a nonexclusive, royalty-free license to publish or reproduce the
published form of this contribution, or allow others to do so, for U.S.
Government purposes.
Army Chemical School, Radiation Laboratory, Fort McClellan, Alabama
3 Laboratory for Nuclear Research (KFA), Juelich, FRG
-203-