roid then resulted in a substantially larger dose. The total estimated dose from the various iodine isotopes to the child’s-giss was it 1006 rads, ° glandsreceived: with a range of 700 to.1400an additional 175 rads from external gammatadiation. Details of these calculations have been given by James and Ng andare presentedin Appendix 2. Although the skin overlying the thyroid gland wasfrequently the site of “beta burns?as shownin ; Figure 20, the deposit of radioactive materials in this area probablydid notaddsignificantly to the thyroid dose, since most of the beta irradiations were too weak to have vegenetrated to the depth of o the gland. = “w Previous Thyroid Studies Until 1963 no thyroid abnormality was detected in either the exposed or the comparison population, except for one case of asymptomatic diffuse thyroid enlargement seen in an unexposed woman. It has not been possible to perform basal metabolism rate determinations, but careful physical examination of the thyroid and a variety oftests of thyroid function have been performed during the previous surveys. Pratein-Bound lodine.**> The serum proteinbound iodine has been determined by the methods ofFoss et al.*? at Brookhaven National Laboratory, the Boston Medical Laboratories, and Bio-Science Laboratories, Van Nuys, California. In addition, estimation of the butanol-extractable iodine of serum was done at Bio-Science Laboratories, and also column chromatographyof the serum iodine by a modification of the method of Galton and Pitt-Rivers.*° In-severaliingtances the capacity of thyroxine- meglobulin:(BG) was mea- sured at NIH by a spethodaloseribed previously.°” The reafilts of analygestor iodine in serum are Figure 20. “Beta burns” of neck (subject No. 39, March 1954). The area over the thyroid was a frequentsite of burns. care has been taken to ensure that glassware and syringes were not contaminated with iodine. This can be seen by the fact that the total iodine is not markedly greater than the PBI and by the normal values for PBI obtained in 1964 on membersofthe medical team, whose blood wgs obtained at the sametime and udder the same conditionsas that of the natives. The elevation in PBI could be due to a general increase in serum PBI in all the Rongelap population,or it could be due to the occurrenceof some genetic difference, so that a'substantial fraction of the pepulagon showabnormally high PBis and the remainder of the population is norma dn.the,first case, a plotofthetevel of PBI versus a cy ofoccurmgnee at that level would sh Bs emai:distribution, oxe itjanthe shownin Table 14. (See Appendix3 for complete whole several occasions andwith:-geveral different meth- would ¢ aay anda‘family tree wauld'show chispesing, th ecise typé.de fepending on a the managebt} Figure‘29%distribu- protein-bound io@tire data.ATests apparentthat on ods the average seruaiprotein-bound iodinein the inhabitants of botlgRongelap and Utirik is higher than normal, and that fram 16. to 64% of the natives on Rongelap and 90% on Utirik show values that are above the normal range by American standards. No8ignificant differences in the PBI levels have been noted beqween the group that had been exposedto radiation and the unexposed group. Thefirst results showing an elevated PBI were obtained in 1958, and since that time a the digplaced Bing up- ; n ihe aedaemii case, the. dissribat oncurve tion cumeg of eel Seepsus | cidence at that level, shows no evidencefor a bimodal! distribu- tion. The low number of PBI values between 7.75 and 8.0 ug% seevis.to be due tegtatistical fluctuation because ofthe small numbérs ofcases. Furthermore, the elevated values (defined as those above 8.0 4.g%) did not show a familial pattern of distribution. It appears, therefore, that the eleva-