30 thyroid lesions is more recent, has not been on treatment long enoughfor evaiuation. The zn utero case was not placed on thyroxine treatment until after nodules had been detected. Thyroid lesions developed in several persons who were presumably taking their thyroid medication regularly and who appeared to be euthyroid with normal thyroxinelevels; on the other hand, thyroid nod- ules disappeared in two cases (Nos. 53 and 40) during thyroxine treatment(in the latter case, they recurred and were surgically removed). 1. Follow-up Careful follow-up studies on the subjects who had cancer, including whole-body scans at Tripler Army Medical Center, have shownnosigns ofrecurrence. No clear-cut evidence has been seen of further development of nodularities in the thyroid remnants in the benign cases. Because papillary thyroid carcinoma progresses very slowly, tong continued follow-up observation is necessary. No deathsor acuteillnesses have been associ- ated with the thyroid abnormalities. Morbidity has beenrelated to the developmentof reduced thyroid function resulting in varying degrees of hypothyroidism andin one case of hypoparathy- roidism following thyroidectomy. The lackofstrict compliance with the thyroid treatment program in the operated cases involves the potential danger that serious hypothyroidism may develop, particularly in patients living on the outer islands and therefore less frequently seen. roid funetion has been greatly improved bv the use of radioimmunoassay techniques for measuring Ty, T3 (triiodothvronine), and TSH.*%-89 Stud- ies of serum iodoproteins, which had resulted in artifactual elevations in the serum PBI in the Marshallese, are discussed below, as are more re- cent measurements of thyroxine-binding proteins and serum thyroglobulin. Studies of thyroid function havealso included tests of radioiodine uptake and excretion on several occasions. In the field these were done with a somewhat primitive apparatus(Figure 38). 1521 was used to minimize the dose to the thyroid. More extensive and sophisticated tests were done on patients brought to BNL for evaluation priorto sur- gery elsewhere. These included tests of thyroid radioiodine uptake and scans (technetium-99m) before and after TSH stimulation; determination of basal metabolism rate, cholesterol, antithyrogiobulin antibody leveis; and a variety ofciinical chemistry tests. In a number of cases a small amountof 131[ was administered prior to surgery and the function of excised thyroid lesions and sur- roundingtissues was studied by autoradiography. One 48-year-old man (No. 40) briefly developed acute thyroiditis after TSH administration. 2. Studies of Exposed Rongelap People With Thyroid Abnormalities Evidence of thyroid hypofunction and reduced reserve was seen in a few of the children prior to surgery (Nos. 2, 20, 33, and 65) and to a greater degree in the two bovs who developed myxedema &. STUDIES OF THYROID FUNCTION* 1. Procedures Measurementof circulating thyroid hormone has been an importantpart of the evaluation of thyroid function in these surveys. During thefirst 10 years it was done by PBI analysis and subsequently by ion-exchange chromatography(thyroxine by column). Since 1972 evaluation of thy- *Thyroid uptake studies were done at Rongelap in 1965 and 1971 by Dr. J.E. Rall and in 1966 and 1972 by Dr. J. Robbins. At BNL thyroid function studies were done by Dr. H.-L. Atkins. PBI determinations were made by the Clinical Chemistry Section at BNL andby Bio Science Laboratories, Van Nuys, Calif., who also did other serum iodine analyses. T, and T; by RIA, and dialyzable T,, TSH, and TBG by reverse-flow electrophoresis were analyzed by Dr. P.R. Larsen at the University of Pittsburgh and more recently at the Peter Bent Brigham Hospital, Boston. TGB analysis by RIA was done by Drs. M. Gershengorn and J. Rob- bins, and TG analysis by Drs. M. [zuma and J.-L. Baulieu. SO0bIN1 Figure 38. Thyroid function testing under field conditions, 1966.