1 .OID LESIONS IN MARSHALLESE EXPOs( TO FALLOUT (AS OF MAY, 1974) Marshall [sland Group (radiation dose-gamma) Age at Exposure Rongelap (175 rads In-utero Rongelap (on Ailingne In “ETG° gamma exposure) Island -69 rads gamma exposure) Utirik? (14 rads gamma <10 11-16 >16 all Estimated Thyroid l dose-rads 175 + ? 675 - 1440 335 - 675 335 - - Thyroid Lesions Percent Malignant Lesicns Percent2 15 1 3 17 5.3 (1/19) 5.4 (2/37) 4.7 (3/64) 33.3 (1/3) 89.5 12.5 8.1 32.8 (17/19) (1/83 (3/37) (21/64) 9 716 all <10 360 : 480 132 - 33.3 ee 16.6 4833 22.2 (4/18) 40,- 80 0.0 (0/53) all - 3.2 (5/157) Rengelap unexposed <10 >10 all - - Likiep unexposed (1970) <10 - all ~ exposure) Thyroid Surgery >10 . 22 - 1 - 0 - 4 0.6 (1/157) 2 3 5.8 (6/104) 4 1.6 (1/61) 0 0.0 (0/31) 0 3.6 (5/137) 0 4.5 (6/133) 3.6 (7/194) 4.7 (5/106) 2 2 0 - - - - - - t3i, 132, 135, 6555 plus gamma dose Based on number of original people exposed. in group. In parentheses number of cases/total number 3ahe thyroid is considered fully developed by age 16. “ptf ference of opinion as to whether or not one lesion was malignant. was that it was benign. , 1.0 (1/104) Majority opinion The more energetic shorter-lived isotopes of iodine contributed less to the total thyroid dose in the Utirik peopie due to later fallout. One might surmise also that the biological effectiveness of the thyroid dose per rad would be less in that group. OF ifteen children 10-17 years of age at exposure in this group received estimated thyroid doses between 22 and 40 rads, In addition to thyroid lesions, one case of acute myelogenous leukemia was discovered in September 1972 in a 19-year-old Rongelap boy who had received 175 rad gamma radiation at one year of age. He died November, 1972.