= 14 In obtaining the derived values in Tables I and II,
MPLB anc MPC, for Pu-239, a QF=10 was employed.
implies,
25 mentioned above,
This QF
that the particles of Pu-239,
wiich emit alpha particle radiation, are 10 times more effective
in inducin¢e cancer than X-rays.
Although the irradiation of
tissue by insoluble plutonium particles is highly nonuniform,
no DF value has been assigned to these particles and hence, a
DF=1 was enployed in determining the derived values in Tables I
and II.
Ideally,
the DF should be determined by the ratio
of the cbserved effects in an organ following uniform and
nonunizor= radiation of the tissue with the same radionuclide;
For #xamcle:
oF = Numer of cancers
°
Number of cancers;
(nonuniform irradiation)
{uniform irradiation)
Since Girect exserimental data are not available,
it is
=
mecessary ic derive the DF for insoluble Bu-239 particles from
teral cata.
In a subsequent section, we shall sresent
the bioicgical evidence that strongly suggests that a DF=l
crossiv underestimates the DE for insoluble particulates of
.
this
.
.
radionuclide,
are greatly
.
20
in error.
$12 be shown that the biological data strongly
I~
*
that the derived standards, MPLB
t
I~
it
itr
it
a3
iw
cr
et
Q
ur
cr
lh
fu
"
fs
atd
ath
th
wi
Hi
J
anda MPC,
consecuently,
ft
Q
rg
Pu-239 and,
such parzicles one shovld use a DF=115,000.
t@s as well to other aloha-emitting actinices
reticulate form.