With the above digression, we can now raturn to Fig. 3.
from the fipure
che data
[t
that it fs not appropriate, and Ls misleadin;,
in terns of a “linear-no-ctireshold” ralationashin.
Co presene
rnacnec, as
shown also tn Fig.
3,
the data should Se presented as distributions of
cells, the area of
the distridution fepresenting the total amount of
ait
2xoosure,
AS noted avove,
series
of
cell
the dcistclouctons
doses,
dose-rasponse curve,
exactly
in itd
in Md are frequently of
that what
is
quantally is
needed
to
as
is
in Fiss. 2 aud J peovice
done
organ
essentially
evaluate
the
the same size}.
number
of
(it then
hit cells
Seeoses cle:c
that will
Increasing cell dose.
shoun schematically as
Such a function,
is
the S-shaped curve in Fly. 2.
the data
the cell
re
is
An actual curve iar
in Fis.
these curves is now discussed,
One such curve
1,
is shown ta
following which their
the HSEF
The use of the HSEF is snown schematically in Fig. 2.
multiplied by
4
summarized.
"Use of
i
wee oH yr ae de,
aha elhahulend
{.,¢.,
ternea a hit-sice
nas been ceveloved (4-9),
chromosome abnormalities, derived from
The use of
Pespuns
the peobabilicy of a cell quantal vtesponse,
effectiveness function (SEF),
or all of
to yradeq
the cell equivalent of an organ-dose response curve,
as a function of
derivation
Jdetermliaing aa
(tie numbers of antnals subjects
ceiatlonshio that will perovida
Fig. 7.
in
“mae
ve
Sit siz2 alstribictons shown,
eis
west
7 UT
Ty
aa mey
- on
wee
wee my
fake ee
the carcresponding point on
the fraction of hit cells
&
wh
For any one,
one simply nultiplies
ar
take
7 tte
wt ee
the HSeF.
~f
hee
moa
Dita
re
2
aad
-
moe
~ 2
The resuiting droducts,
responding quantally at each cell point on tre
distribucion, are shown as the much smaller distributions within the larger
ones.
The area under each of
fraction of exposed cells
the smaller aistributions yields
responding quantally,
marked E-l, E-2, and E~3.
excess
incidence,
risk assessment.
It is
the
the exposures
Ic is this fraction, of exposed cells responding
quantally for a given amount of exposure,
cisk evaluation.
for each of
the total
total risk
in that system, of
that is
the end product of
to the cellular system,
che end point,
t.8.,
the
the
for expusure —, of
the
Thus such a value can be readily obtained for any amount
of exposure to a radiation of any LET, or sixcure, without any requirement
Ll
500 1k b8