LATE EFFECTS OF RADIOACTIVE IODINE IN FALLOUT Figure 15 are shown results of the 1°71 up- take into the neck as a function of time. The uptake patterns fall into two groups. One group had an abrupt rise in neck radioactivity, but this was mostly blood iodide. From there on there was very little change, indicating that these individuals had very little accumulation of iodine in their thyroids. Two of these three subjects were the severely retarded boys to whom Dr. Conard referred, and the results indi- cate a severe deficiency of thyroid function. The third was a girl who had had a sub- total thyroidectomy approximately a year earlier. The 1#7I study showed that she had little or no remaining thyroid function, perhaps due to radiation damage to the thyroid remnant. The other three individ- uals had what appeared to be normal uptake of 18?I. One of them had had a subtotal thyroidectomy 1 year before. One subject, who was later operated upon, was a girl with moderate retardation in growth who was found to have a depressed thyroxine level in the blood and so was mildly hypothyroid despite the normal uptake of 1271. As part of this study we looked to see whether the iodine that was accumulating in the thyroid was being organically bound. There had been somestudies earlier (17, 18) on patients treated with radioiodine for hyperthyroidism indicating that radiation damage to the function of irradiated glands may affect different chemical systems differently. The finding was that iodide trapping proceeds normally whereas or- 1233 In Table 9 we have attempted to summa- rize some of the pertinent findings in the Marshallese who developed clinical thyroid abnormality. The subjects with thyroid nodules are listed in the order in which the abnormality was detected. The results of kinetic analysis of 1%7I studies are presented in Table 10. The data in these two tables are presented here in detail since, for the most part, they have not appeared in the earlier publications. The 182I studies performed at the Brookhaven National Laboratory were done on the patients who had come to the United States for surgery. These studies were done preoperatively. The methods were similar except that the neck counts were taken with and without lead interposed between the crystal and the neck in order to correct for the extrathyroidal radioiodine “seen” by the counter, and the measurements were continued for 6 hr in some cases. Computer analysis of the data obtained at the Brookhaven National Laboratory in June 1966 was evaluated in several ways: with or without the corrected neck counts using a lead shield, with or without inclusion of urine data. None of these made an important difference in the value for thyroid accumulation rate, but the uncorrected data gave somewhatgreaterreliability. The very low urine excretion rates in some cases are probably due to incomplete urine collection and re- sult in comparable errors, in the opposite sense, in the computed thyroid fraction. In ganification does not, and the iodide that Table 10, uncorrected neck counts are used except for the data at Brookhaven National charged by giving a competing ion such as ied in the Marshall Islands in March 1966, accumulates in the gland could be dis- potassium perchlorate. The Marshallese patients were, therefore, given 500 mg potassium perchlorate by mouth at about the 4-hr point, and neck measurements were continued. There was no discharge, and therefore we could conclude that there was no defect in organification in the subjects with normal 187] uptake. Laboratory, June 1965. In the group studblood 18?I was measured at 2 and 4 hr in order to calculate the iodide space. All subjects had been off levothyroxine therapy for at least 3 weeks unless otherwise indicated. The TSH level in serum was kindly performed by Dr. William Odell of the National Cancer Institute by a radioimmunoassay method. ieseltaeinali beensia Volume 66, No. 6 June 1967