THYROID LESIONS IN MARSHALLESE EXPOSED TO FALLOUT (AS OF SEPT. 1972) Marshall Island group (radiation dose-gamma) Rongelap (175 rads gamma exposure) Rongelap (on Ailingnae Island-69 rade gamma exposure) Utirik’ (14 rads gamma exposure) Rongelap unexposed Likiep unexposed Age at exposure Thyroid surgery Malignant lesions percent 500-1400 89.5 (17/19) 15 5.3 (1/19) > 20 all 335 16.5 (3/26) 39.6 (21/53) 2 17 7.7 (2/26) 5.7 (3/53) 335-500 “ < 10 200-500 all - > 10 < 10 > 10 all < 10 > 10 all < 10 > 10 131, 132, 133, 135 I 2 nased on number living. Thyroid lesions percent < 10 11-20 all lnose from Estimated thyroid dose -rads 1323 40-80 224 12.5 (1/8) 0 16.6 (1/6) 0 14.3 (2/14) 1 12.5 (1/8) 1 - - - - 0.0 (0/55) 0 - 5.8 (4/69) 3.2 (4/124) - 0.0 (0/61) 0 - 0 - 0 - ~ - - 3.8 (5/133) 2.6 (5/194) 0.0 (0/31) 4.7 (5/106) 3.6 (5/137) 1 l 1 1 0 - 1.4 (1/69) 0.8 (1/124) - - plus gamma dose In parentheses number of cases/total number in group. Sone child 10-17 years of age at exposure received estimated thyroid doses between 132 and 200 rads. 4p ifteen children 10-17 years of age at exposure in this group received estimated thyroid doses between 22 and 40 rads. >the more energetic shorter-lived isotopes of iodine contributed less to the total One might surmise therefore thyroid dose in the Utirik people due to later fallout. that the blelogleal effeetivenesa of the Lhyreid deaa per rad would be leaa in that group. ern addition to thyroid lesions, one case of acute myelogenous leukemia was discovered in a 19-year-old Rongelap boy who had received 175 rad gamma radiation at 1 year of age. 235 IOT4BYS