Growth and development studies of children using anthropometric
measurements and bone age radiographic studies have revealed a slight
retardation in growth and development of some of the boys exposed at less
than 12 years of age.
The greatest retardation was noted in several children
exposed between 12 and 18 months of age.
noted in the female children.
Only slight immaturity has been
The next slide shows the relatively greater
retardation in skeleton age in exposed boys than in girls.
shows the statural growth retardation in exposed boys.
The next slide
The cause of the
growth retardation was not known until the recent detection of thyroid
abnormalities.
This will be discussed below.
There were several isotopes of iodine absorbed from the fallout,
131
I,
132
I,
133
I,
135
I.
Thyroid accumulation of these isotopes resulted
from consumption of contaminated food and water and possibly to some extent
from inhalation.
Since no direct measurements of radiation in the thyroid
gland were made it was necessary to use an indirect approach, that is, the
radioiodine measured in the urine analyses which were collected at 15 days
after exposure.
By extrapolation it was estimated that about 11.2 ywCci 131,
was accumulated in the thyroid gland during the exposure.
The adult gland
was estimated to have received about 160 rads from the iedine isotopes in
addition to 175 rads from the gamma radiation.
glands of children was quite likely higher.
The dose to the much smaller
It was estimated that the dose
to thyroid glands of children less than 4 years of age was in the range of
700 - 1400 rads.
"Beta burns" in the neck region over the thyroid, as shown
in the next slide, were not considered to have added any significant dose to
the thyroid gland because of the low energies of the beta activity.
we
2
Annual examinations had always included careful thyroid examinations