“100
bp
a
fi
al
Single. I”
a
(31
Time from detonation ta intake
Intake
I he
r
x
e°
CF
aet 2
=
q
"
2
a
ec
v
uw
Sf
2
3 Lok
Ee
2
.
x
2
Prolonged intake
°
:
be
L.
r
ol
4
to tl
lo
oo a tl
be a
100
oust
10
Time fram Oatanation to Intake (hr)
.
he
AiG. 2. Approximate infinity dose to thyroid from
single intake of the 1!*! and its tellurium precursors
from 10,000 fissions. This figure is used with Toble
3 in the preparation of Fig. 3
‘|
Pop
20
.
net inn te
do
pa tt
30 40 50
100
top te
tt lh
200 300400 *500_—.
Duration of Intake (hr)
*
2
ate ae
wee,
3
-
.
.-
a
‘ wd
FiG. 3. Approximate relative infinity dose to thyroid from short-lived {
isotopes and 1!5! for case of prolonged intcke. See Table 3 for sample
calculation of these curves
When ingestion or inhalation of radioactive fallout material occurs,
it is important to be able to estimate the dose received.
Mere, for the case cf radioiodine, is a procedure for determining
ww
the thyroid dose s'ven present activity or initial intake
ce. The incase. glong with thelr,
of Te: =
cart of which sau
disintecote within the hoist:
[++
To estimate the sriginal rate of intuke of B® from a known activity in
the thyroid at a later date, one can
extrapolate according to the physical
and biological cleeays of T'* only.
This method ignores ti.ake factor b
and thus overestimaies the original
intake; it also ignores faetor c and
thus uuderestimdtes the orginal in-
AKLE |
ou
take The carne’ fo whi theses 7
afect theo amecver Jareneds treon time
Of original intake ction detomaiteon ane
woe eee coe thee tape
WO SS SSIES SEGAD VIRS
Co.
.
Mass number
_.
oe .
ad
ao!
a
(Te)
Oo
1S]
the duration of intake.
pet Be t eee
es
_
ea
{r)
(Xoo.
ve
error would nut pe any greater than
(fF's3
-
132
134
~Smin-- 77hr
The exact steps are given in che
.
— 2.4hr -+ stable
<10min— COmin— 2l
hr
— 5.8 day — stable
<Tmin-+
6.7 hr
.
1. Initial rate of intake of I'!, Re.
<10 min > 43 min > 50.8 min— stable
15.3 min (~10%)
135
Ts
following sections. Thesymbolsare de
fined at the head of page 40. Two
examples are given on pages 40 and 41.
95min 8.0 day — stable
133
/
other tnhercnt waeeetainties.
—
39 br
Elowever. eati-
mates of the effects of ignoring these
two factors iwlicste that the overs]
‘9.2 hr-—+ 2.1
Assume that the rate of intuke decreases according to the physical decay
of the isotope. Then activity in the
thyroid changes with ttme thusly
dA
a7
X 108 yr — stable
Rye! — (A, + ADA
Vol. 14, No. 2 - February, 1956
x"
L
x
&
Po
a
z.
~
ike.
39
in
.
bea
YT
7
he
.
~
~
a
>
an
-
ai.
ih
-
.
-
+
-
.-
a