ae
2age 3 - Geneva Douglas
Effects (Comments):
A.
Study Group 1:
Conard, R. A., et al, Thyroid Neoplasia as Late
Effect of Exposure to Radioactive Iodine in Fallout.
#2 (October 12, 1970)
JAMA, Vol. 214
Thyroid Lesions in Marshallese, March 1969
island Group
(Radiation
Age at
Dose-Gamma) Exposure (yr)
Rongelep
(178 Rad)
<10
>to
all
Rongelap
(69 Rad}
<10
>1d0
Utirik
<10
Rongelap
<10
all
(74 Rad)
(unexposed)
>10
al]
Estimates
Thyroid Dose (Rad,
Radioactive lodines*}
Thyroid Lesions
y (%ajT
500-1.400
89.5 (17 of 19)
1601
wee
275-550
55
oes
$5-100
14
Malignant Lesi .15
® (%)i
BB def HE
8.8 ( 3 of 34)
59:20 TD)
39.6 (21 af 53)
5.7 (3 oF SF
é
0.6 ¢ Oof 6)
12.5 {¢ lof &)
7.1¢
1 of 14)
9.0 ( O af 40}
a
§.1 1. 3 of 59)
17 r of SH
wae
3.0¢ 3 of 99}
1.0 (1 of 39.
ves
0.01 Oof61)
>10
eae
2.3¢€ 3 of 133)
all
aes
1.5¢(
3of 194;
"Dose from Tey, i224, 1434, 1asy,
+Based on number now living.
Children 16 to 20 years of age at exposure received doses between 160 ond 500 rad
~
The highest incidence of thyroid lesions (89.5%) nas been noted in
the heavily exposed Rongelap children who were less than 10 years
of age at time of the accident.
In 1965 one case, and in 1969 three
cases of malignant lesions were discovered. These recent findings
greatly increase the author's concern about radiation-induced
neoplasms in the population.
'Microscopically the thyroid carcinomas
were considered of low grade malignancy..."
The exposure of the Rongelap people was not comparable to exposure of
populations from reactor accidents where radionuclides are chiefly
absorbed from contaminated milk obtained from cattle grazing on
contaminated pastures.
It has been generally believed that radioactive iodine exposure was
less effective that X-irradiation in producing thyroid lesions based
primarily on the fact that few thyroid tumors had beer noted following
radioactive iodine therapy.
It seems likely, however, that the
scarcity of such findings is relative to the high doses of radiation
used (S to 10,000 rad or more in the treatment of hyperthyroidism,
and 50,000 rad or more used for ablation of the gland to ameliorate
Symptoms in certain diseases). Such doses are probably so destruc7ive
that they preclude proliferative activity and malignant transforma ion
in such damaged glands.
“t