The

fact that D is effectively exposure and not dose also provides

into what the basic problem is when one attempts,
express

the

as

insight

is done in Fig. 1,

tv

biological respouse of cells in terms of a single variable,

i.e., as E, or the proportional parameter D.

This

is depicted in Fig. 3,

the lower panel of which shows conceptually two of the curves given in
Fig.

lL.

In the upper panel

is a three-dimensional schematic, on the

exposure-No/N, plane of which is depicted the same curve and labeled
poiats shown in the lower panel.
cell dose distributions,

1.e.,

On the Ng NpTcelt dose plane are the

the relative numbers of cells dosed, as

funetion of the cell dose, z.

the
per

las|
quar
appr
tal

z

~

cont:

o

z

cénei

Teads

Rach

CELL OOSE z
a

.

i

HIGH LET

wo

iF

z

2

=

Ps

“hit”

1D

eo

t
1

18

Low LET

The

\

from r

E(ehdeh'O)

Fig. 3 A three-dimensional schematic plot, designed to show
that any single point on a given conventional absorbed dose-response
curve doés not represent a single value of cell dose, Rather,
oe
each potot,

for any quality radiation, represents an entire

distribution of cell doses, as shown on the plane representing
Ng/Ne VS Z.

-

heac”

,

these

j

inveate
Substir
QOn-ana

idea of

Feinend

8Pplieat

Stochas,

recent (

2G 14

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