- 23 - as in the Marshallese is whether.thyioids being cperated for the be subjected to total thyroidectomy. [gross lesions should Very often the malignant leBion found in an ir- radiated gland is not the lesion that prampted exploration. Between 1956 and 1960 when the risk of carcinoma of the thyrpid following radiation to the head and neck became an issue, we had available the rpcords of 200 indi- viduals who had received x-radiation between 1939 and 1949 for lymphadenitis in this hospital. amined for thyroid nodules. explored. Of those that were living, 60 There were 12 found to have masses Three carcinomas were found; the remaining were ad 10 thyroids were Post-mortem records of one additional patient in the group showed carcinama. additional lesion of the several removed and considered to have been an "atypical enoma’' has recentl: recurred and now shows microscopic features of carcinoma. PARTICIPATION IN OTHER WORK IN THIS LABORATORY CONCERNING RADIATION EFFECTS In recent years, the principal investigator has. participated projects concerned with radiation effects on the thyroid. Marly in several other the observations and analyses of findings have contributed to the investigation 1. The opportunity to study the Marshallese patients has been This is a very unique situation where a low but a critically oncdgenic dose of radioiodines reached the thyroid of normal persons. These were n to hyperplastic thyroids of Graves' disease treated with T31y are more sensitive to radiation than the former. thyroids in contras cells of the latt This differenca is illustrated by t far greater dose of 131; necessary to cause therapeutic reductior in function of the normal thyroid of the cardiac patient than the amount used to pratuce a similar effec in the hyperplastic gland of Graves' disease. Thus, it may be ceived, the radiation effect was far less in the Marshallese where than in Graves's disease where neoplasms are rarely produced. Thq ed that rad for r neoplasms were for similarity between