to utilize the“Llinear,
non-tnreshold” function required
ta the currentl-
used approach.
However,
tc may be useful,
ited
into, but differs
Fiz.
5.
from
The liaeac curve
the number of hit cells,
to show how the prauposed approacn can te
the present system.
ta
the
or
the
exposure X (the open circcle
fisa of 4 cell being hic,
om Che curve carkead Ry).
given radiation are pravided
If
this distribution is
tight panel,
to deterrine
for a given
This single curve
{tn the upper rivht hand cornet.
those
ia Figs. 2 and 3,
This
is nuocmalized te lev.
then multiplea by the HSEF, shown I[n the center
shown in
distribution represent
[Lllustrates tn
The hit size distributions fer the
the product will represent
responding cells,
aistribution
to
ts
left mand panel permits ome
is tor any LET radiation, or ulxture.
distrfoution, as opposet
This
the distribution of quantally
che cight lower panel.
The areas under tails
tne number of hit cells in the upper nocmallzesy
that responds quaataliy—-nultiplying this value by
of exposed cells given Sy
the aunber
Che open circle in linear curve Py ta
che ieft
panel yields the total cisk for exposure £, shown as the open circle on
’
curve
Rx
q
.
It
in Figs.
\
is emphasized
that
the “normalized distributions” approach cepicted
5 ts for illustrative purposes only.
threshold” relationship,
referred
Neither “Linear,
non=
nor distributions toc different LET's need ce
to or used in practice
(it is superfluous
to provide a curve for
Lag cissa of a Alt versus exposure- the distribution of hit sizes
sutfices).
That is
nixtures of LET's,
microdosimeter.
to say,
for any given exposure, whatever the LET or
only a single distributton would be recorded by the
Direct application of
“risk coefficlent”.
Thus,
che HSEF would yield the requiced
ito practice,
the cell dose approach conle
obviate
the need for multiple “dose response” curves (Fig. 1),
replace
the concept of LET entirely.
not mean
the mean of
That is
to say,
the energy depositions in tissue.
deposited in the cell TCV--the cell dose.
and it could
the “T" in LET dows
[t means
the anount