f Cc oo D Sy THE FOREIGN SERVICE OF THE UNITED STATES OF AMERICA 6 April 195) Tr. Rokuzo Kobayashi Nationa] Institute of Health Welfare Ministry TOKYO Dear Dr. Kobayashi: On Merch 26 we received two samples of urine from patients at the Tokyo Univeristy Hospital. I am happy to be able to report at this time that the radioactivity of these samples is so low that the deposits of fission products in the tissues of the two patients can be accepted as well within the limits of safety. The results follow: MASUDA, Sanjiro YAMMMOTO, Tadashi ~ = 720 disintegrations per minute per liter 510 " " " " " Data on the individual radio-isotopes will be telegraphed to me in another few days. It will then be possible for me to be more quantitative in estimating the dose from absorbed fission products. However, it is most certain that the storage of long-lived radio-isotopes is insignificant in these men, AS you know, the rete of excretion of fission products at any given time efter absorption bears a relationship to the quantities de~ posited in the various tissues, The principal radiochemical constituents at this time are due to Sr 89, LallO and the Rare Earths, These are ~ isotopes which have relatively short half-lives and are eliminated from the body with comparative rapidity either by radioactive decay or excretion. In the case of these patients, Sr90 is most certainly an in- significant fraction of the total absorbed radioactivity. The permissible urinary excretion, considering the tsotopes involved, would be greater, by a large factor, than the values rported above. I note that the newspapers continue to carry occasional statements of the Japanese investigators to the effect that the prognosis for the fishermen is adversely affected by the fact that long-life boneseeking isotopes are deposited in their tissues. It is regrettable that the public continues to be misinformed in this respect. Certainly the results reported above argue convincingly that only minimal, medicslly insignificant amounts of fission products have been absorbed into the tissues of the two patients for whom results are available,