TT 250; aos T a T | , tT T ' 250r T T r T — . “tf r —T SKELETAL AGE ASSESSMENTS GIRLS 1957 - i965 SKELETAL AGE ASSESSMENTS BOYS 1957-1965 200 : i SKELETAL AGE (MONTHS) I75— ‘ A TKR wn . - ‘ x \ 150K ~ 2 is0- (25 a4 2 . = | i 4 2 | . i i00r 2 | (25h 4 1 4 © 10Or I MALES EXPOSED =-—— MALES UNEXPOSED o———o ry 50r “ 4 4 a 25 50 =5p . 50 75 100 4 os . 150 125 4 [75 200 i 225 , 250 FEMALES EXPOSED ———s Loa a s 25- | HC = 75 ; 4 a | al ' a FEMALES UNEXPOSED 2#——~ Lo 25 _, , | 4 50 75 1 100 a 125 | 150 t 175 L 200 i 225 250 CHRONOLOGICAL AGE (MONTHS) CHRONOLOGICAL AGE (MONTHS) Figure 18. Figure 19. THYROID FINDINGS exposed on Rongelap: 150 rads (from direct mea- During the past 3 years, the developmentof thyroid abnormalities in a significant number of the people exposed on Rongelap, and in one from the Ailingnae group,has resulted in extensive thyroid studies and surgical intervention in some cases. The examination and therapyofthe first 6 cases of nodules of the thyroid gland have been measurements on pigs removed from Rongelap described.'**?:-* Since then, the numberofcases of nodules and hypothyroidism has increased to 18, and the newcases are described below: The Radiation Dose to the Thyroid Glands surement of urinary ‘*'[),*° 100 rads (by indirect plus Marshallese urinary excretion data),** and 160 rads (based onrecent recalculationsof early data”’ - see Appendix 2). The last recalculations were based on analysis of pooled urine samples mainly from adult Rongelap people taken 15 days after the detonation; an estimate of the one-day thyroid content of '*'I was 11.2 pCi (5.6 to 22.4 pCi), assuming that 0.1% (0.005 to 0.2%) of the maximum thyroid burden (not corrected for physical decay) was excreted in the urine on the 15th day. The dose of 160 rads to the adult thyroid was The dose to the thyroid gland from radioactive 7 calculated from oral intake and inhalation of the iodine is determined by its uptake by the gland,its half-life in the gland, the size ofthe. gland,.and the. relative proportion of the severwlradioisotopes of iodine involved. Therelative distribution of radioiodines in fallout dependij onthe type ofexplosion but in general is well knéwn. In addition to '*‘I, the isotopes *"I, ‘1, and to a-less extent '*?I contributed significantly to the thyroid: dose. The only direct data available on the Rongelap peopleare radiochemicalanalyses of pooled urine samples taken 15 days and longerafter the fallout. Three separate estimates have been made of the dose from radioiodines to the thyroid glands of adults varloyg,lodine isotopes, considering their fission _ yield, ‘the average energy deposited in the thyroid gland per disintegration, and the time of absorption. The dose to the thyroid glands of children <4 years old was then calculated by means of these factors with consideration of pulmonary function and the thyroid size of a child that age.” The main source of iodine ingestion was considered to be water, andsince it was being rationed at the timeofthefallout, it was assumed that the children drank the same amountof water as adults and therefore had the same thyroid burden of radioiodines. The small size of the childhood thy-