On the basis of these consideratims, the tissue sections ‘were gradedlas to
positive or negative evidence of radiation effect by the following system:
0
+
-
++ +++ -
Nothing to suggest radiation effect
Uncertain category ~- some features suggested there might be
radiation effect - cften more samples of tissue would have
to a definite decision
Definite radiation effect
Marked radiation effect; at least some architectural distortio in
addition to bizarre nuclear forms
After the observations on each individual slide had been recorded and Feported to
Dr. Conard, the slides were grouped so that all slides from the same indivifual could
be reviewed and a single grade registered for each thyroid. In some cases, there had
been considerable variation in the appearance of the tissue from one area tb another.
In such cases the evidence for radiation effect was much more convincing inj some areas
than in others. Where only a single slide was available a reevaluation andj grading was
all that could be done.
When the code was broken and the judgement as to radiation changes was] matched
against the radiation exposed (so far as was known), it was found that
ther
was a
surprisingly close correlation between exposure and the recognition of radiftion effect
in the thyroid.
See Fig. 13.
Tissues from 7 of the 16 Marshallese who
werg
thought
to have had the greatest radiation to their thyroid had unequivocal evidence in tissues.
Most of the Marshallese were singled out as being at least suspicious. Onelfof these
that was definitely positive was considered a Marshallese control (thyroid Fissue from
post mortem examination from the hospital on Majuro) that later proved to b@ an
individual that had been exposed but had developed no gross thyroid pathology (335 rads).
Changes in the thyroids from the Japanese bomb casualties showed minor fer only
Suspicious change when they were arranged in order depending on their distayee from the
epicenter.
Those nearest seemed to have the most suggestive change.
This {find ing, if
Significant, was surprising because the amount of radioiodine in that fallajt
was small
considering the presence of otherTadloactiveématerials that were in the falldut.
Only debatable changes were seen in the tissues from the Utah group, most of which
were not thought to have been exposed to significant fallout.
considered positive for radiation effect.
One case in
]§ was
At the present time, it is imposspble to
determine for certain just how much radiation exposure these individuals
recbived.
Certainly the majority had not lived in the fallout area when the largest faflout occurred.
Most of these thyroids were adenomatous.
‘Some of those in which suspicion
was
raised
were in glands that contained considerable lymphocytic thyroiditis accompanifd by
hyperplasia. - The only gland that was classified as positive had been considfred normal
in the pathology report but in this study there seemed to be an occasional
ge radiation
nucleus.
These observations served to illustrate that subtle degrees of radiatiah
caused by radioiodine in the thyroid can be identified.
.
changes