{
t
:
t
i
Mark and Bustad report similar findings in sheep/,
.
Though the dose to
|
. the thyroid gland in the Marshallese was generally considerably below the
t
.
dose of 134y used for therapy of hype <hyroidism it is likely that the
|
:
|
7
|
Co
:
eo
doses received by some of these children were in excess of the optimum |:
{
-
.
.
.
!
.
‘carcinogenic range and therefore the true risk per effective rad may be
greater in this group.
.
. -! a
.
The paradoxical finding of greater risk in the
older group appears to be in line with this reasoning.
-The two stunted |
t
' Marshallese boys who showed almost complete atrophy of their thyroid
glands with no evidence of nodular development are probably comparable
°
i
_ to those cases of hypothyroidism developing in patients years after
No " -Yeceiving radioiodine therapy.
-
|
It should be pointed out that the thyroid = 4-0
|
J
igs
exposures in the Rongelapese were slightly different from patients treated. 0/7)
with 131] because their thyroids were not hyperplastic when exposed and at ne
.
_-
hw
'
t
least part of the radioiodine isotopes to which they were exposed were ©. _
in addition their exposure was complicated, |)
of shorter half life than 131, ,
.
-by gamma radiation.
lead “
o
There were some factors secondary to radiation exposure that might
" have enhanced the development of thyroid lesions in the Marshallese. .Iodine. =~":
:
|
.
-
oe
et
deficiency or presence of goitrogensin the diet did not appear to be among. * :
these.
However the physiological stresses of :puberty and pregnancy may
' have played a role in the development of the lesions.
°
!l
-
For instance thé
|”:
children during or near’...
development of 10 cases of nodular goiter in the
. ole
I
.
,
the time of puberty might indicate that this stress may have enhanced nodular
development.
In 3 females that developed thyroid nodules later the demand
of multiple pregnancies may have been related:
However since the latent
-
DOE ARCHIVES |
793