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Table 2 indicates that about a quarter of a million
Utah infants were exposed to fallout iodine 131, with
an indicated average thyroid dose of 1.3 ~ 10 rads.*
The significance of these exposures is not the size of
the average dose (which is srall) but in the enormous
number of irradiated children.
THYROID CANCERS
The natural occurrence of childhood thyroid cancer
is extremely low.
Values from Mustacchi and Cutler
indicate that by age fifteen years only 25 thyroid
cancers are expected to appear per
gillion
children.®
Thus only about six "natural" childhood thyroid cancers
are anticipated in the 250.17 Oeosed Utah children
by age fifteen.
The fraction of these so called
"natural" cancers which were in fact induced by medical
X-rays may be appreciable.
In a series of childhood
thyroid cancers collected by Winship and Rosvoil,
about 80 per cent showed a history of prior irradiation.”
in the United Kingdom only about three children per
million develop thiyroic canccr by age fifteen, 1°
X-rays can indice thyroid cancer,
About 20-30 years
ago, it was common in some hosnitals to X-irradiate
infants in the neck region for benign conditions.
Thyroid
cancer has followed °-n an unpleasantly large number of
these exposed children. ?
Beach and Dolphin? 1
founda
reports of 132 post-irradiation thyroid malignancies
in the published medical literature;
the additional
number of unpublished cases remains unknown.
They
analyzed the relation between incidence and dose in
4673 exposed children for whom the individual doses were
obtainable.
The incidence of thyroid cancer increased
with dose to 1.7 per cent at 500 rads.
assuming
*Vyearliercrudemethods (see Ref. 5) yielded an
estimated thyroid dose averasing 4.4 rads to this
population.
I am pleased at the agreement.
DOE ARCHIVES
43