SeeRe, LATE EFFECTS OF RADIOACTIVE IODINE IN FALLOUT Figure 15 are shown results of the #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 indicate a severe deficiency of thyroid function. The third was a girl! who had had a subtotal thyroidectomy -approximately a year earlier. The 1871 study showed that she had little or no remaining thyroid function, perhaps due to radiation damage to the thyroid remnant. The other three individuals had what appeared to be normal up- take of 187]. 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 171. 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 some studies 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 organification does not, and the iodide that accumulates in the gland could be discharged by giving a competing ion suchas _ 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 #97] uptake. my 1233 In Table 9 we have attempted to summarize 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 187] 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 *?I studies performed at the Brookhaven National Lab- oratory 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 somewhatgreater reliability. The very low urine excretion rates in some cases are probably due to incomplete urine collection and result in comparable errors, in the opposite sense, in the computed thyroid fraction. In ‘Table 10, uncorrected neck counts are used except for the data at Brookhaven National Laboratory, June 1965. In the group strudted in the Marshall Islands in March 1966, blood 1871 was measured at 2 and 4 hr in order to calculate the iodide space. All subjects had been off levothyroxine therapyfor at least 3 weeks unless otherwise indicated. The TSH level in serum was kindly per- formed by Dr. William Odell of the National Cancer Institute by a radioimmuno- assay method. oe ee ee oe Volume 66, No. 6 June 1967