The verytrapid cleara 19 /of ‘radioactivity’from the Gl tract contras
:
with the relatively slow bjglogical loss observediin the respiratory sygtem.:
At 5 days fgllowing gn inhalation exposure, 42:pezy cent of the. maximum:
agtivity of.the respipatoryptract is still present.is'The loss of activity
_ from the lung: for the! firsfa}5 days was carve
&.
theiinhalatipft simulantgt} ‘and III, The curve
ther‘respiratory system canrbe described by, 2: te’constants, ‘The inifial
rapid loss of:material (habfwlife about 10 hr is) yyobably associated wif
piratory tract, whil
J theirapid upward movemathe material ‘in t
the’ second :process#“oor of. approxim
associated’y ith the:plowexlogs' of the smaller:p
alveolar tidgye. With sigiulan
activity following Ndminietseti
te
rapid than’¢
t following
rial.in the. ting, ‘Fglio
F
‘the alr side ‘of:‘thealye
lis “Jepositedsen
‘stayed. nedevel:‘in the
concentration appeared
Eyaluation of the Inte rngRadiation Hazard
.
“While calculationof rapiationdose from fa}lout with any.degree of:
precision is difficult,
pproximation based- onexperimental data igs
feasible and was performed here, In order to'evaluate the*dose to in
dividual tissues jollowingran inhalation exposure, fhe activity
tissue as a function of time was determined (Figs 5). The ‘Qieatest
activity per gram ee as observed in the thyroid at 1 heéfollowin re
exposure, At this time ‘the activity in the GI tract (includin ‘content
was next highest, followed by that in the respiratory tract, iN
/
an
ae
The tota} dose received by each organ for comparable ener ies ago
:
course, praportional toithe area under ite-curve: (see Table:3}, The:
thyroid, for’ example, x ceived 170 rad, ° ‘This'was by forthie highest”
dose received by any off the tissues measured during the Istiay expexiox
:
mental period studied, ifhe ratio of the dose received by thhe:thyzal
Ny
veeoN
2 getERE
10
1s
i-~
jen
WP
Ir
{>
IQ
Iq
(Zz
a
ri
- l 2 -
Spares on u
:
=
he
ne
* Calculation. was performed by ene integration,