fc4 -‘Reprinted froin Ravsarion Researcu, Volume 19, No. 4, August 1963 Copyright © 1963 by Academic Press Inc. Printed in U.S.A. | 401823 “yb L95'70 tyes ce RADIATION RESEARCH 19, 655-658 (1963) Il. Long-Term Cs’ Turnover in Man as Measured by a Whole-Body Counter’ STANTON H. COHN, BETTY ROSOFF,? ERNEST A. GUSMANQO, anD HERTA SPENCER? Medical Research Center, Brookhaven National Laboratory, Upton, New York INTRODUCTION In order to ussess the radiation hazard of the fission product Cs!*7, it is necessary to determine its long-term turnover rate in man. Part II of the report describes a long-term study of Cs!4* made on five patients. Measurements of whole-body reten- tion were made with the Brookhaven whole-body counter. It has been foundthat the technique of radiochemical analysis of excreta is of limited sensitivity for determining whole-body retention at very long periods of time after tsotope administration, In order to assay the radiation hazard, it is further necessary to estimate the retention over the normal life span of man on the basis of the data obtained. Thus a mathematical model must be developed from whieh long-term extrapolations can be made. In this study, data analysis was carried out with the use of a computer in order to determine the parameters of the mathematical functions that best deseribe these data. METHODS The Brookhaven whole-body counter used in this study has been previously de- scribed (1). The counter consists of an 8 X 4-inch NaI(T]) crystal detector with three 3-inch photomultiplier tubes. The detector is suspended 19 inches over the adjustable cot holding the patient. A 400-channel transistorized RIDL (Model 34-12) pulse-height analyzer is employed. Cs!""C] was administered intravenously as a single dose to two patients and orally to three patients, The descriptions of the patients and details of the isotope ’ Research supported by the U.S. Atomic Energy Commission. * Present address: N.Y. U. Research Service, Goldwater Memorial Hospital and Department of Physiology, Health and Hygiene, Hunter College, New York City. *Present address: Metabolic Section, Veterans Administration Hospital, Hines, Illinois. 655 rerositomy —bV4 RECORDS COLLECTION LUARSHALL ISLANDS — BOXNo MEOICAL DEPT PUBLICATIONS The Medical Research Center Brookhaven National Laboratory Upton, L. L, New York oo .