Qograted in an Ud mode,
the
problem must be approached trom the Ph,
This
ecidemiological and accident statistics standpoints.
because any transter of
radiation energy
to
the
i.e.,
is, of course,
individual cells
takes
nlace only as a cesult of stochastic (1.e., due to random processes)
between a charged particle and a target-cuntaining
Thus we first need, with LLE,
che
(fractional) number of cells hit.
Also, because energy is deposited in the
TCV in separate, discrete amounts,
we need also the amount of eneray
deposited,
1.e.,
the "hit size” or "cell dose".
dose varies greatly from cell
The magnitude of the cell
to cell, and ranges
amount of kinetic energy carried by the particle.
dose,
to be relevant, must be registered
from zero to
In other words,
initiation of
occurs,
that, while with HLE only
whysical quantity organ dose
is required
the
in individuals at the level of
biological organization at which the
The important conclusion is
the maxinun
the
response of
interest
.,
cues
volume (TCV) within the cell.
reesre a.
encounters uc collisions
the one
for risk evaluation, witn LLE at
phantom response
Eye
number of cells
can be accomplished
is determined electronically.
This provides
if
hit
the
tor the short
recovery time needed in order that many hits per cell can be recorded
(i.e.,
if an array of phantom cells registers a total of x hits during an
exposure time t,
then a single “rapidly recovering” phantom cell will also
register x hits during a time xt).
use of
the phantom will, with
the appropriate scaling factor, provide us with the
least two probabilities needed
namely,
Next,
to the probability
and injured.
the phantom must record separately every discrete hit on the
phantom cell, as well as
it must provide
deposits
first of at
in principle for epidemiological evaluation,
the number of nits per cell, equal numerically
that a cell will be hit, dosed,
say,
This property of
in
the amount of
the energy deposited.
the distribution of
the magnitudes of
the cell TCV's, or tie cell doses.
That is
This distribution of cell
radiation, or any mixture.
doses neatly in order of
the stochastically delivered cell
increasing magnitude. Thus we have
the exact
analogue of what is commonly used in pharmacology and toxicology
-208-
9812910
to
the energy
doses must be obtainable for any given exposure to a single type of
The electronic phantom arranges
ilkacre ee
and dosed during any given exposure period,
the
i Tee
to register
to
he SEfeate te
to be able
; ina, wives,
The first requirement,
te
least two separate quantities are needed.