The following is a brief outline of the observations made on these patfents: 1) To determine the amount of the treatment dose taken up by the thyrpid, and ith almost_dai:ly thyroidal measurements, determine the character of the diskppearance urve of Sly from the gland. 2) To follow the concentrations of 151r in the serum at the same inte}vals as he above observations were being made on the disappearance from the glard. 3) To determine the amount of 131] extractable (with water saturated butanol) rom the serum. 4) To prepare serial quantitative chromatograms to show the amounts of various odinated compounds in whole serum and in extracts of serum (hours, days and ollowing the administration of the treatment dese. These serial observatio hat are induced by the radiation. 5) To determine the subsequent function of the irradiated gland by f t31y uptake and hormone production and to relate these to the pretreatmen 6) To mike observations on the suppression of circulating lymphocytes ytes each time the above observations on blood were made. ears of the study. This was done o 7) To relate the bicchemical data to the effect of the total dose of alivered and to the ultimate clinical course of the disease. The rise and fall of various compounds (such as thyroxine and triiocdo he appearance of certain other compounds (such as mono-iodotyrosine, diicd nd thyroglobulin), after the treatment dose reflected not oly the effect o adiation, but also probably reflected the features of the abnormal physiolo isease before the radiation effect becomes significant. Retrospectively, atterns of iodinated compounds in the blood, the alterations in rate of re adicactivity from degraded thyroxine to the thyroid, and the subsequent testi he functional capacity of the gland permitted an analysis of what had oc Because of the large amount of labor involved in the study of each pat his study, only selected individuals were used. During the early part of ti he personnel on the study devoted almost all their time to these studies. s the cther long term studies have evolved, more selectivity of patients total of about 2,500 chromatograms have been prepared on approximately 225 serially studied over the course of about 15 years. These very extensive da ot only been analyzed but also stored for reference and reviewed from time time in he light of subsequent clinical developments in these patients. Many of findings re related to other observations described under this contract. ontribution of the 1311 Kinetics Data of the Public Health Service Follow-uq] Study When the United States Public Health Service undertook a follow-up study of a arge number of 1311 treated patients in various centers particularly interedted in hyroid disease, the responsible investigator of this contract was asked to eon he protocol committee and subsequently became chairman of that committee. aboratory became one of the 19 centers in that study. In the course of the ata accumulated at various centers, it was found that there was considerable feview of variation