a
eae
eee wre
-— we
ohysycians,
who
ad
had
atm
no
.
eet
wee
dtrect way
gE
ae
ee
went
te
determining «nat
tissues were recelving from a give exposure.
he ke ee
che
That is
~~ «
tutor
“3
wee
of nersil
to sav, ome Must use
a “cell phantom” tf one wishes to estimate the dose to a Living cell.
we ust outline
cell phantom.
the requirements ana lecessary charactertstics of
However,
only
the dose
4avptoach
to
tne Ladividual urpan of
the problem from the Ch,
statistics standpoints.
radiation enersy
(L.@., due
to
This
tlisues
Cumuoc of
taterest, ~2 must
1.e., epidentlolugteal and acciceur
is, of course,
tanes plac2
because any
transfer of
only 45 a result of
s7sena
bet.zen 2 ch:ryved
the (fractional) number of cells nit.
Also, because
1.e.,
the “nit slze” or “celi dose”.
magnitude of
the cell cose varies greatly from cell
trom zero to
the maximum amount of kinetic energy carried by
the
dose,
to
be
Thus <e
the TCY in separate, discrete amounts, we need also
the amount of energy deposited,
Thus
regiiced
al
particle and a target-containinsg volume (TCV) within the cell.
energy is deposited tn
unitke
ia an “td* rode amd
to random processes) encounters or collisions
first need, with LLE,
Sucn a
in so dulnhg we cust Be ever mindful that,
the eicly (and peesent) physiclans who operated
Thus
relevant,
must be
registered
The
tuo cell, anc ranges
in
tne particle.
[ndivideals
ace
tre
level of bDfLological organization at which the
initatioa of
interest occurs.
that, while with KLE oniy
The
imporctunc conclusion is
the response cf
the
one physical quantity organ dose is cequired tor risk evaluation, witn LLE
least
The
and
two
fodependent
quantities
First requirement,
cosed
during
electronic.
any given
many hits per cell can
register a
to >
total
of
x
f2
verfod
Te
requires
the shect recovery
be recorded
hits
rcequtrea,
-
a.e
exposure
It can then have
are
wT
iD
at
during
(L.e.,
that
tiie needed in order that
tf a number of phantom cells
au exposure
Cine
t,
then a
cecovering cell will also register x hits during a time
of
the phantom will, with use of
with
the
first
of
at
least
eoidemtological evaluation,
numerically
to
the
tyvo
xt).
Tr
the appropriate scaling factor,
probabilities!
namely,
probability
the
the
that a
needed
nunber
cell
will
of
in
hits
be hit,
provide us
principle
per
cell,
doses,
for
equal
ana
tnrured.
=o
;
The number in a group expected to respond quantally attec a alven exsosuce
provides the numerical probability that such a response will accur.
Thus,
the term probability will be used interchangeably with tne terus “rraction’
or “proportion” of equaily dosed quantal responders and the term “risa”
will be used fLaterchangeably sith the oruportics or inefdence of
stuchastically, and thus unequally-dosed quantal respunders.
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