- 13 -
rem is the unit of Dose Equivalent (DE)
8
,
;
The DE is obtained
.
by multiplying the absorbed dose in rad by modifyina factors
to correct for these observed differences
if the effect.
As
a
consequence,
effect will be the same
in the magnitude
the magnitude of the
for a given DE regardless of the
rature of the radiation or the manner of radiation.
B.
Modifying Factors
At the present time,
One is the Quality Factor
two modifying factors are employed.
(QF) which accounts for differences
in producing biological effects among various forms of
radiation.
The other is the Distribution Factor
which accounts
(DF)
for the modification of the biological effects
when a radionuclide is nonuniformly distributed in an organ.
For example, the DE for X-ray to bone tissue is determined
sy usind OF=1
and DF=1, while that for Pu-239
determined by using a QF=10
in the bore is
(to account for the greater
effectiveness of alpha particle irradiation)
and a DF+5
(to account for the peculiar distribution of Pu in the bone) 2”.
.
A DE=50 rem from X-rays or Pu-233 would thus
induce the same
number of cancers in bone but the absorbed dose from the X-rays
would be 50 rad while that from Pu-239 would be only 1 rad.
18/
NCRP Report No.
39, Op.
19/
ICRP Publication ll, Op.
cit.,;
Pp.
cit., p.
81.
2l.