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. (131.132. I, This will be discussed below. There were several isotopes of iodine absorbed from the fallout, I, 133—0«135 I, 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 pCi 131) was accumulated in the thyroid gland during the exposure. The adult gland was estimated to have received about 160 rads from the iodine 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. Annual examinations had always included careful thyroid examinations §001293 a,