PRIVACY ACT MATERIAL REMOVED THE FOREIGN SERVICE OF THE UNITED STATES OF MERICA 6 April 1954 Pr. Rokuzo Kobayashi Nationa] Institute of Health Welfare Ministry TOKYO - Dear Dr. Kobayashi: On March 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: _ - 720 disintegrations per minute per Liter S10 tt " "" " 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 quanti-~ tative 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. 4s you know, the rate of excretion of fission products at any given time after absorption bears a relationship to the quantities deposited in the various tissues, The principal radiochemical constituents at this time are due to Sr 89, LallO and the Rare Earths. These are significant fraction of the total absorbed redioactivity. The permissible urinary cxcretion, considering the %sotopes involved, would be greater, by a large factor, than the values r-ported 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 thet the public continues to be misinformed in this respect. Certainly the results reported above argue convincingly that only minimal, medically insignificent omounts of fission products have been absorbed into the tissues of the two patients for whom results are available, £ passorreg N1"00zS uid aod 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, Sr90Q is most certainly an in- % 2 o % % %%. ek °