1232 NATIONAL INSTITUTES OF HEALTH CLINICAL STAFF TABLE 8. Annals of Internal Medicine Kinetic Analysis of }”I Studies (March 1965) in Subjects Without Thyroid Abnormality Group No. Subjects Urine* Thyroidt Thyroid Fraction} Marshallese—exposed — 12 Marshallese—unexposed 9 1.10 (0.34-2.57) 0.67 (0.33-1.27) 0.40 (0.25-0.65) (0.17-1.99) (0.23-1.47) (0.26~-0.77) 0.81 North Americans 2.0 0.79 1.0 0.52 0.33 Mean and rangesare given. * Fraction of extrathyroidal iodide excreted in urine per day (\¢1). t Fraction of extrathyroidal iodide transferred to the thyroid per day (Asi). . . Aa _ +t Theoretical thyroid uptak (—“~). Theoreti yroid uptake { Tx to the thyroid gland. A 18*Te generator was used, capable of producing a supply of 1871 for a period of several weeks. Radioiodine accumulation in the neck was measured + hr after the oral dose and at hourly inter- vals for approximately 4 hr. (Details are given in reference 12.) Urine was collected at the end of this time and measured for 132], The data were analyzed by Dr. Mones KC! 0 20-- + ‘ _---4 4-785 + <t 10k > | ~~g— a x o > . +L “" _o‘e e = 0 ~~a-7 i 0 i 1 2 i 4 L 6 HOURS Figure 15. Neck accumulation of I in subjects with thyroid abnormality. Values are gross neck counts, as percent of dose, uncorrected for blood background after oral administration of “J. Computer analysis of these data indicates that 7% of the extrathyroidal iodide pool is “seen” by counter. At the vertical lines, 500 mg perchlorate (KCIO,) was given by mouth. 54; /8= Case 2 (partial thyroidectomy); the neck potassium A = Case © = Case 65; @ = Case 5; [] = Case 3; @ = Case 69 (partial thyroidectomy). The calculation used the gross neck uptake, uncorrected for extrathyroidal iodine, and the analysis indicated that the counter “saw” more than 99% of the thyroidal ra- dioactivity and that 8% of the neck radioactivity was extrathyroidal. In Table 8 we have listed the fraction of the body iodide that is taken up in the thyroid per day and the fraction going into the urine per day. e+ w Berman, Mathematical Research Branch, National Institute of Arthritis and Metabolic Diseases, using the computer program that he has in operation for kinetic studies and particularly for thyroid studies (16). Interestingly enough, both of these values compared with United States values are low, again an abnormality for which there is no explanation. The balance between these two depressions was such that when the theoretical maximal! thyroid uptake is calculated it actually comes out higher than is normal in the United States. Although the low urinary excretion rate might well be due to incomplete urine collection, which was very difficult under field conditions, this does not significantly alter the calculated thyroid accumulation rate. I joined the survey for the first time in March 1966. At this time we were interested in doing some further studies on the individuals who had developed thyroid nodules, and we were able to carry out a few such studies. The patients stopped their thyroxine therapy 3 weeks before testing. In Piggripe rssamyengey fee amount of radiation that it would deliver