:
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100
TABLE 35.
.
Animal
Age of
burden
Man
Code
|
Liver
.
Kidney
Spleen
Lung
/
Cortical
100
253
49d
03
100
100
lly
66
100
134
0.5
0.9
26d
48d
26y
83
85
166
100
100
100
66
65
604
0.7
1.0
0.2
0.4
1.t
0.5
0.8
1.3
100
205
0.6
0.7
1.0
100
100
100
100
100
100
100
175
213
580
204
44]
252
316
0.4
0.8
0.9
100
312
07
67
72
73
TH2‘>)
TH3)
TH4®
TH5)
Average
marrow
_|
02
41d
35d
38d
18m
22m
12m
22m
Bone? +
“bone
49d
Average
Rat
Tissce DistrinutTion oF THoROTRAST™
|
Red bone
marrow
—_
8.4
19.1
2.4
1.9
5.0
5.8
14
Il
7.1
12.5
|
‘*) Concentration of thorium (?"Th)/g of tissue as % of liver concentration.
®) Ratios are based on 7Ra activities assuming equal f; values for all the soft tissues.
‘) Rib and vertebra, respectively.
TABLE 36.
OrGan DistTRIBUTION OF THOROTRAST
IN Man (222TH)
W, Organ
Organ
Liver
Spleen
Kidney
Lung
Cortical bone
Red bone marrow
Total
Bone -++ marrow
wt in
Standard
Man, kg
1.7
0.15
0.3
1.0
7.0
1.5
10.0
least about the physical and chemical prope
C,
Thorium
conc. rel.
to liver
% in
organ
Cw
(100 CW/
100
205
0.6
0.7
1.0
12.5
170.0
30.8
0.2
0.7
7.0
18.8
v
13.6
0.1
0.3
3.1
8.3
7.1
227.5
71%)
(from
tions and approximations must be made. The s
mathematical model, and the one which assun
Table 35)
227,5)
100
(9) The figures in the right hand columngivethe fractional
retention of #%2Th in the organ, relative to the amount in the
whole body. Amounts of Thorotrast contained in organs other
than those listed are assumed to be negligible. Thorotrast in
lymphnodes, though probably not negligible, has been ignored
because of inadequate data.
») The danger in extrapolating from the figure for bone
which contains marrow, is demonstrated. This value for the
whole skeleton is approximately three times that obtained by
extrapolating separately for cortical bone and red bone marrow.
not be carried out rigorously since they depend on
metabolic parameters which are inadequately understood. For this reason a numberof simplifying assump-
Thorotrast, is presented in an Appendix to this
The following results have been obtained on th
of the equations contained therein.
RESULTS AND DISCUSSION
Tissue distribution of Thorotrast (732Th)
Measurements were made of *3?Th concentrat
tissues from 6 humans and 7 rats. Average conc
tions in the various organs are summarized in
30, All have been normalized with respect to the —
content of the liver, the organ which containstl.
jor fraction of the total body burden. In this way
of the difficulties which arise in making extrapoi
to the whole body can be minimized, e.g., those
nonuniform distribution of activity in each orga
certainty in the ratio between the weight of the s
measured and that of the whole organ (particul:
the case of bone marrow), and inaccuracies
quoted amounts of Thorotrast injected. On this
no significant differences between man and the r
evident in the extremely meagerdata.
Extrapolation from the data for man (Table .
the whole body has been made by assuming
weights for the standard man in accordance wr
recommendations of ICRP.‘The pattern of dis
perh
MENS R tS