from July § meas- urement.)
.
t = 27 days (May 19-
EXAMPLE: Human: Inhalation
June 15)
dh, = 6.0366 dav!
y= 0.0204 day7t*
.
Thus
On May 19, 1953 the highest concentration of activity in the air due to
fallout that has ever been recorded in the U. 5., outside the Nevada Test
Site, occurred at St. George, Utah. It amounted to about 1.3) pe/im?
averaved over 24 hours. The total radiation dose to the thvroids of the
people at St. George from inhalation of the isotopes of I is estimated to be
0.302 rep as shown in-the following tabular calculation.
0.37 =
Ke fems8.0808.27 97 0.107)27)]
0.0204
Ro = 0.189 uc/gram/davy.
Now we determine the infinity I!"
dose using Eq. 2.
Estimate of Radiation Doses to Thyroid of Humans From Inhalation
Dix = Ad (Ay + No)
where: A = 55 RoE = 55(0.189)(0.2)
=~
= 2.05
an2 Dy. = 99
224
Time
after
dstinnalion
Cy
;
itr I J131
reps=|is the infinity
Fission-
Average
product
Jissionproduct
achivity
(mefanenees)
Fraction
activity
originally
retained
tae
Added does
of fission
product
that is
. Fiaste
I'l achwity
reaching
thyroid
Gmttine)
Infinity I“!
dose to
thyroid
Coma
from shortlized I
Total
tsotopes*
infinity
treo)
(cen)dose
4.3
0.16
§.00
0.0304
O.121
0.155
0.105
0.47
0:7
1.1
1.80
0.19
0.0230
0.0110
0.0012
0.0018
0.030
0.003
0.003
0.041
0.004
at.
To estimate the dose from short-
.
.
.
.
2-7
lived isotopes of I enter Fig. 3 with
these parameters:
.
;
7g
10-14
14-18
.
start of intake = 3.5 hr —
18-30
duration of intake = infinity.
The graph indicates a ratio of approxi-
é
mately 0.45.
.
.
But this is uncorrected fer biological
decay, ie., it is based on the assamipr
tlon that the bivlugical decay constant
.
.
.
for
"
tie
noes
TANT.
an
US
are
MANTvanis
west
than the phrsies! decay eonstunt.
4.0
12.4
9/3
0.62
0.043
0.35
1.56
0.104
0.014
3.77
0.29
0.074 0.097
0.005
Tote 0.302rep
* Based on 0.83-meter?/hr air intake and acsuming that 75% of the activity will be
initially retained either in the lungs or find its wayinto the gastrointestinai tract.
» Based on assumption that 73% of initial intake of both Te precursors of I'*! will
remain within body until decayed to [F),
¢ Assuming 23°; of initial retention of I'3! (either in lungs or gastrointestinal tract)
reaches the thyroid.
T {nitial dose rate = (53}(0.2)(me of I per gramof tissue) in reps per day. Infinite
tiose
It
= Initial da~e rate yids + M.).
‘From Fig. 1.
Multiply these ratios by (A, + 4.) /A, for I'S in man.
iS nersssqrs te cortert thos cath. :
matltiotving ov tle factar?
’
—.
oom
\
.
=_
ard
77
toe Te
Melo RD = gal
The Gntietc
Tron. shouts
:
tos
q
Boo
lo
vey
tee ta tie rovrei
wea
Jaf
.
.
PO NS Le pen
toons
tO
rt
the
1
wp
lod
Los, seuy
if
°
=
see
Cte ley
.
sites
pentecdalil 2
oe
Bice ety
a
prices
f tdubeedtlse
et
ia
vi
ted
ye
1
aR ey
ieenme
Tet
Lind
as
Bis
Se
A bl
[te
oa
3b7
2
eres
Ula
ettets
ol
ae
te
Gath
Gieet
Gest
LL
1uL)
and Public Hesith Nu f2 (Harvard Universiry
Press, 1954)
60 1-SO1
So1-1,001
28tt
1401
eetelamave and avrothvred User.
BIBUOGRAPHY
2 J. B. Stanbury. er alo URnderie Cotter.”
Harvard University Moncrraph in Medicine
§ L. Van Middlesworth, Necttosrs 12, No, a
7
* Bisiogical half-life in sheep thyraid~ ds
about 34 days (5).
Tee feutante & Table 2.
1
tary
ual
HY} HO
:
.
Gu
~
eee
ran
mo
oo
Ve
eed
dt
fe
1. -4O
ooh
4b
0.55
-——
0.08
4014
7
v 2
irre
fez
1s
Leia
1
2.140
3
1
Peon. bas
~
18a0
1,885
7:
-
Los
1. 5t
mae
i.45
kay
W900
2,121
0.71s
2152
~* a=
0.383
ede
2,155
2,150
VU. 82H
0.500
Q.454
be
exes where biological decay in the thyroid is sigatfeant tor 1-8!) multiply last eobures
(by the faetor (A, o Ap /Ae.
41
kb
aw
fh
2
kw
EO
OL
4
&£@
me!
Pils iscteoreetod tor Uiojestenl decay as deseribed ain footnote 4 Table £0
4
&
aon
;
2.060
Vol. 14, No. 2 - February, 1956
FE
> wy
2052
tony
;
IS4
12
-
0.0005
0.003
Poet
178
a2
(142
205
ives
.
3.6
tye
ue
.
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4,200
4,439
240
ara
ne
* Baselbon Pie, 2.
SO
a
ton
blo
2Ob-SUt
N55
.
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S/d
8(-101
i, H. F. Hunter, N. EL Pallu:. Neenecsies 9,
,
-,
PR et et eg
WTS
sae
3.419
-
Cannon For Ost
a
Ati
3
peorthe
‘Ut
a
51-461
~
mos, Ts;
Fe tet ue
75
so. 5, C-2 (1951)
4
(Fie [it for par fintte
phecotd dave intuke fram
fad fave ta ened of periad
ip
a
G
tay ar foterl en eryies
Cres ree
[airs
guys
2,209
weet ee
au
-
F
Relitice
Oper
font
to
OU
rors
Cee
ws
11-201
uu
cette
Pei Foo
E
ul t
1th
yf
.
Mean «f
rabag af
wae eee
ated
L25
yt
D
25
isu
a
eT
.
.
a
fe
c
oo
velbiler stiuetue and
a
E
te he OT
begs
.
Peat
teogae
tan;
~ ae
.
eka aap
.
vee
jhhot
,
~
mets
°
_--
A
Loot ede ae
--“
~~
TABLE 3—Samplte Calculations for Figure 3
Doves 0 inding dae ee
Bb
=e
uk
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