Where
the cucves
become congruent, aC
the curve, each cell has
recelved a
summation of eneryzy censtties
then
it is clear
Che uppec high-expesurs fart
larzse number of hits.
from these multiple hies
that even though
the
if one
tie “cell
in size,
and smaller.
There
{s
.
then no reason to eviluate separatel: the
each discrete
Hit.
It
is adequate,
high-expesure
regions,
practical purposes,
tne vartunce of
cose™,
tre rein «fll tecome
for practical ceasons,
the mean dose.
the cell dose anc
ftdentical.
Staller
cisx foe
siuply
to «use
Ta other words, in tnrese
the organ dose ace, for sal
Then, and most iaportantly, one cana
characterize and predict the probability of 2 biological response
cell population, or in
the organ itself,
the absorbed dose D to
Che organ.
However,
splits
as one goes low2r in exposure,
even though
in the
in terms of a singie parameter,
{it is seen
into independent components, Zz and Rue
value of Z,
the
indiviaual “lets constituting that
“dose” vary ywreatly
the summed energy density as
calls
the variance is
that the exocsure
note that tne expectation
large,
remains constant, so treet
the only cellular parameter that can increase with increasizg exposure ts
the Ry or the number of hit sizes
dose
the
per exposed cell.
Thus, «ith &LE
to cells and oryvans alike can iner2ase because of multiple hits, and
one variable,
However,
D,
with LLE,
ae
increases;
Note
it
ec
{is
adequate
neither
.
fs oly
that while LLB has
predict a
dose
tye
the anuaber
only a small fraction of
exposure,
the
to
to
fan
of
the
response
cells
1.
<
calls dosed
its counterpart
aor
na
in
tne
aw
ixic cin
the
indiviczal.
reaa dose
we
:
tirease
in sacro accicents, and inat
the exposed pooulation is hit with increasinz
there is 20 analogue, with macro accidents, of HLZ exposure.
reasoas for
this ts
accident rate
that,
for practical and ethical reasons, if
other hand,
w=
The
the
in given population increases above a very srall fractisn per
year, even drastic action is likely to be taken.
With radiation,
the accident rate can be increased at will,
course of minutes,
seconds, or less.
It {s only because of this
which may permit interactions between the hits,
seen only with high-level exposure of cells
15
on the
so tnat any 6
given
cell can readily be exposed to dozens or more severe accideats,
Sooub
.
ia tre
‘fact,
that the “quadratic” term,
to ionizing radiation, exists.