34 Effects of Faliout Radiation on Human Beings Table IH. Total thyroi Table II. Thyroid tumors (consensus diagnosis) through ]987 Adenomatous Nodules 17 Rongelap (67) Ailinginae (59) Utirik (167) Comparison (227) Adenomas Follicular Cancer Occult Cancer 2 3 _ l _ 4 4 — 4 ! Gy. When diagnosed andtreated with thyroxin, normal growth ensued [4]. With the developmentof thyroid tumors, the exposed people were placed on thyroxin to suppress TSH production. Later they were taken off suppressive therapy to measure thyroid function. Twelve individuals were biochemically hypothyroid and of course were replaced on thyroid hormonetherapy to suppress developmentof thyroid neoplasms after the study was complete [4]. Thyroid Tumors Table II lists the types of thyroid tumors detected and removed. and the pathologic diagnosis made by consensus of six endocrine pathologists. Of the 53 thyroid tumors diagnosed, 15 were cancer [3, 4]. Adenomatous nodules began appearing about 10 years after exposure in the individuals who had thyroidal doses greater than 3000 rem (Fig. 11). With time the number of cases diminished with none being observed in the 34th year after exposure. = -‘rF i . +P 2 fae = os a a . T T I T T vr t . “ . — . e 1 - . _ s th se of s soa oped 6 t 6 4 oo et ee 1 1m z a _ x tT 7 T T : T 1 7} BENIGN NODULES (AQ) nreorevroinism THYROID CANCERS Age Oe Adult Male Six- Year-Old One- Year-Old Newborn In Utero, 3rd tri. In Utero, 2nd tri. Adult Male Adult Female Fourteen- Year-Old Twelve- Year-Old Nine-Year-Old Six- Year-Old One- Year-Old Newborn Jn Utero, 3rd tri. In Utero, 2ndtri. Table IV. Total thyroid Sifo i Age Adult Male Adult Female Fourteen- Year-Old Twelve- Year-Old Nine- Year-Old Six- Year-Old One- Year-Old Newborn In Utero, 3rd tri. In Utero. 2nd tri. Adult Male rl 4-250 259-S0C 901-1009 1001-2000 2001-3000 3001-4000 «4001-5000 & YEARS POST-EXPOSURE Fig. 11. Temporal appearance of adenomatous nodules of the thyroid as a function of thyroidal dose (divide dose in rem by 100 for Sv}. Ronge a Adult Female Fourteen- Year-Old Twelve-Year-Old Nine-Year-Old 2 THYROID DISEASE vs RADIATION DOSE 100 RERUN OF POPUT ATION IN EACH DOSE CAIFGQHY 5 T 1 5 There was a correlation between age at exposure and the appearance of thyroid nodules and cancer. Those less than ten years of age at exposure had the highest incidencein all exposure groups [3]. Figure 12 illustrates the correlation between absorbed dose ofradiation in the thyroid and percent of population in each dose category forall groupsthat developed benign nodules, hypothyroidism and thyroid cancer. The fraction developing benign nodules increased with dose up to an average dose of 40-50 Sv. The fraction with cancer peaks at 20-30 Sv. Hypothyroidism peaksat around 30-40 Sv. Tables III-V show the estimated average and maximum thyroidal dose for the persons exposed on Rongelap, Ailinginae and Utirik atolls. In all cases the dose increases with decreasing age. On Rongelap for example. the average dose in adults was 10 Gy with a maximum of 40 Gy, whereas in the one-year-old, the average was 50 Gy with a maximum of200 Gy. The youngerthe person the smaller the thyroid, and with approximately the same burden of radioiodine. the dose will be proportionally greater. ADENOMATOUS NODULES T — 1 2 AS FUNCTION OF RADIATION DOSE AND TIME TT ee Papillary Cancer 4. 1] Cronkite/Bond/Conard Fig. 12. Thyroid absorbed dose and the fraction of individuals with a given thyroidal dose that develop benign nodules. thyroid cancer or hypothyroidism (divide dose in rem by 100 for Sv). Adult Female Fourteen- Year-Old Twelve- Year-Old Nine- Year-Old Six- Year-Old One-Year-Old Newborn In Utero. 3rd tri. In Utero, 2nd tri.