The dose of radiation to the thyroid, the average thyroid weights of
[the mother
rats, and the average thyroid weight of the offspring by litters is shown —in the
attached Figure 12.
Tt is condluded that animals born of mothers with some thyroid damage do not
display thyroid hypertrophy at 100 days of life, which is canparable to adblescence
in man.
At the present time, the autoradiographs and histologic interpreta ion of
thyroids of the mother rats have not been evaluated since they remain in preparatian.
Since the time that the question was raised concerning the significange of
adolescent goiter in the children of radiated Marshallese people, a furthe# recent
survey made on Likiep Atoll (remote to the area of fallout) has revealed alfew mild
adolescent goiters in native Marshallese.
This excludes a few other goitegs appearing
nndd
1311 om the
All during the life of this contract, the principal investigatur and
have been concerned with the morphologic changes that are produced in
by radioiodine.
The devastating effect of a large dose of radioiodine wi
His associates
did tissue
the complete
loss of thyroid epithelium and replacement by connective tissue is well kn@m.
the hyperplasia of the thyroid of Graves’ disease is subjected to radiciod
the hyperplastic picture of papillary projections into thyroid follicles
a more simple follicular picture. With a large dose of radiation, the fo
distorted and the general architectural pattern of the thyroid is markedly
When
radiation,
changed to
es are
tered 2D
the extent that there may be only scattered surviving epithelium cells in cbhnnective
tissue. These changes are we}}, known and easily recognized, but the more shbtle changes
produced by smaller doses of
IT are difficult to identify with certainty.
Various workers have described a variety of changes that indicate subthe radiation
effect. In trying to identify these subtle changes, we have stressed the récogniticn
of the large bizarre nuclear forms containing excessive amounts of chromatih. Other
workers have placed more emphasis on lymphocytic infiltration, plasma cells land
increased amounts of comnective tissue.
Unfortunately, changes similar to
fhese my
occur in thyroids which have not been subjected to radiation. Lymphocytic
iltration
is a common finding in thyroids of patients with Graves' disease. The presence of
} connective tissue may represent past influences on the thyroid such as
necrgsis,
repeated hyperplasia and involution and varying degrees of nodularity. Obj¢ctions may
be made to using the large bizarre nuclear forms as a means of identifying gadiation
because somewhat similar changes may occur in the margins of areas that are|starting to
undergo necrosis. From the considerable opgymence studying pathologic
charges in
| tissues of patients treated with 199] and
I and the extensive experience
with animal
thyroids that are subjected to various degrees of radiation, we have come td the
| conclusion that a careful consideration of the bizarre nuclear forms is the best clue to
the more subtle degrees of radiation effect caused by radioiodine.