exciude that diagnosis. Nevertheless, the ciinical evaluation required to establish a diagnosis is C. Hypothyroidism, postsurgical: . In 1972 to 1974 it was noted that 11 of 20 exposed persons from Rongelap who underwent surgeryfor removaiof thyroid nodules had associated with its own morbidity. Prominent in this morbidity is thyroid surgeryitself. a procedure that requires general anesthesia and results in a cosmetic defect and the unavoidable elevated levels of thyroid-stimulating hormone (TSH). Because this evidence of postsurgical hypofunction was morefrequent than expected it was surmised that thyroid insufficiency might be developing in the exposed Rongelap population as a whole, rather than being limited to the removal of some normal thyroid tissue. B. Thyroid hypofunction, radiation-induced: Overt hypothyroidism was diagnosed in two Rongelap boys who wereinfants at the time of exposure (Sutow et al., 1965). In addition, subclinical hypothyroidism unrelated to thyroid surgery was confirmed in twelve other Rongelap persons (Larsen et al., 1982). In 1987 a Ltirik man was diagnosed as biochemically hypothyroid. He was two years of age at the time of exposure. and he is the first exposed person from Utirik to have this diagnosis. two hypothyroid children diagnosed some ten years earlier (Sutow et al., 1965). Such an event was likely to be clinically inapparent because all of that group had been placed on suppressive doses of thyroxin since 1965 to prevent thyroid neoplasia. Therefore, after temporarily discontinuing thyroxin, a survey of thyroid function was undertaken, and twelve persons were found to have biochemical evidenceofthyroid insuffi- THYROID DISEASE vs. RADIATION DOSE 100 -— = ooh g S 80 S 70 5 = f = 2 ] T 4 (X) HYPOTHYROIDISM | THYROID CANCERS Z W4 Y ss : = 9p) Aman ZHAYA 1-250 251-500 Vy) Y, Z = S 20- |! [7] BENIGN NODULES s0 = 40> = Poa |! - Z y= HIN y 04 _ Y, YIN YY) YIN YIN YIN VN YIN ON hs VY) CN UN AW KR | TAN ER NY IN ER? NYAS AN 501-1000 1001-2000 2001-3000 3001-4000 4001-5000 REM | Fig. 5: Thyroid-absorbed radiation dose vs. benign thyroid nodules. carcinoma, and hypofunction. F008 LIS 15