Late Effects of Radioactive Iodine in Fallout Combined Clinical Staff Conference at the National Institutes of Health Moderator: Jacosn Rossins, M.D., Bethesda, Maryland. Discussants: JosEPH E. RALL, M.D., PH.D., Bethesda, Maryland, and RoBErT A. CONARD, M.D., Upton, New York R. JAcoB Roszins: During the nuclear D explosion testing in the Pacific Islands in 1954, a combination of circumstances led to the accidental exposure of a group of Marshall Islanders, as well as some U. S. Navy personnerand the crew of a Japanese fishing vessel, the Lucky Dragon, to a rather unusualsort of fallout. In addition to body surface irradiation that led to skin burns and general body irradiation from the surroundings that led to acute radiation sickness, contamination of food and drink with radioactive isotopes of iodine produced pathological alterations of the thyroid gland. Largely through the perseverance of Dr. Robert A. Conard of the Brookhaven National Laboratory, the Marshall Island- ers, both exposed and unexposed, have been the subjects of thorough, repetitive exami- Dr. Conard will describe the findings as they have developed over the ensuing 1 years. He was a memberoftheoriginal expedition dispatched by the Atomic Energy Commission and the U. S. Navy and thus can give us a firsthand report of the initial radiation effects. The major emphasis of this Conference, however, will be on the late effects that have become evident only in the last several years. These observations highlight a subject that is currently of considerable theoretical and practical impor- tance—the effects of radiation on the thyroid gland. The Conference will be opened by Dr. Joseph E. Rall, Director of Intramural Research, National Institute of Arthritis and Bas - participated rican ie nations by teams of observers sent by the -aaae =" = ‘Be Atomic Energy Commission. i a 6 aflji just returned a weeks ago|from the Received March 27, 1967; accepted for publication March 31, 1967. This is an edited transcription of a combined clinical staff conference at the Clinical Center, Be- Ravwoactive‘Teo Poe Parks “ NuCLEAR EXPLOSIONS thesda, Md., by the National Institute of Arthritis and Metabolic Diseases, National Institutes of Health, Public Health Service, U. S. Department of Health, Education, and Welfare. Requests for reprints should be addressed to Jacob Robbins, M.D., Chief, Clinical Endocrinology Branch, National Institute of Arthritis and Meta- bolic Diseases, Bidg. 10, Rm. 8-N-315, National Institutes of Health, Bethesda, Md. 20014. -+$)R. JosepH E. Rati: The heat generated by a, moderate-sized fission explosion generally results ite¢*temapera “dre order of 10 million K. The complexity of the problems associated with fallout generated I214