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in the people extrapolated back to day 1 based on radiochemical urine
analblvses.
Lt can be noted thac the Larcent exposure was to the thyroid
gland from radiogiodines.
Ln addition co the dase imparted by 131,, the
shorter-Lived isotopes b32y 1537, and 145
aise contributed substantially
to the dose.
Absorption of these iodine isotopes was both From inhalation
as the radioactive cloud passed over and trom drinking contaminated water
and eating contaminated
food.
Based
on radiochemical
urine analyses
beginning at 15 days after exposure it was estimated chat about il.2 Ci
of L3lt was accumulated in the thyroid gland at the time of the fallout.
The adult thyroid was estimated to have received abouc 160 rads from the
radioiodines in addition to 175 rads from whole body gamma irradiation,
The dose to the much smaller glands of children was estimated to be
considerably higher; in children less than 4 vears of ape the range
was catimaced to be 700-1400 vads.
Annual examinations have always included carerul thyroid evaluacion.
1,2]. Until 5 years ago che exposed people were considered to have nomal
Numerous serum protein bound iodine determinations had been done and all
en
Since that time increasing numbers of cases of
19 with nodules and 2 other cases with atrophy of the gland with development of marked hypothyroidism.
Only 1 of these cases with a nodular
thyroid was in the lesser exposed Ailingnae group. Thirty-eight percent
of the more heavily exposed group have displayed thyroid abnormalities.
This includes one new case that was discovered in March 1969. A notable
fact is that 90% of the children exposed at less than 10 years of age
Table III shows the distribution of
r in
a a
al
the
Of the 19 children in the
175 rad group exposed at less than 10 years of age, only 2 have failed
to show clearcut abnormality.
[t is noteworthy thac no thyroid
abnormalities have been noted in children that received lesser
exposure, i.e. che 6 children in the Ailingnae croup, the 54 children
in the Utirik group and che 48 unexposed children in the same age range.
Only 4 cases of abnormalities have been noted in the adults, 1 of these
occurring in the lesser exposed group.
It should be noted that a low
incidence of thyroid enlargement does appear in older people (greater
than 50 years of age) of the Utirik and unexposed population (See
Table LIL).
The chyroids of 12 children and 2 aduits have been subjected tc
surgical exploration and the nodules removed. On surgical exposure,
the thyroid gland was seen in most cases to be multinodular as shown in
Fig. 2.
Note the varied size of the nodules from several miilimeters
to several centimeters, some being.cytstic, and some hemorrhagic.
cords
vid.
sent
The
microscopic diagnosis in all but one case was adenomatous goiter, Fig.
3 shows the microscopic appearance with the wide variation in size of
follicles closely resembling adenomatous goiter seen with iodine deficiency.
Some pathologists claim to see radiation induced changes in the thyroid
glands but others do not,
Fig. 4 shows the microscopic appearance of the
mixed papillary and follicular carcinoma with localized metastases ina
en gee
thyroid cases in the populations under study.
wie pee
have developed such abnormalities.
<r ne ee
ture
ame age.
al
"ears
in
Serum cholesterol
At the present time chere have been 21 cases of thyroic aanormalicies,
in
tion
Le
levels had been normal.
nodularity of the thyroid gland have developed in the exposec people.
h
women
urinary iodine excretion were within the normal range.
12 year old exposed giri.
s
posed
ot
We later discovered
that Marshallese people in general have high levels of iodoprotein
which may have masked an earlier hypothyroid tendency.;3] Dietary and
Ten years after fallouc exposure nodular changes were noted in a
c
or
wice
appeared to be in the normal range for these people.
memow: me eee om oe
2n and
Lene ee ee
thyroid tunction with no obvious evidence of any thyroid abnormality.
esulted