The Metabolism of the Fission Products and the Heaviest Elements

An investigation of the assimilation, distribution, retention, and excretion of fission products and the heaviest elements in the rat has been conducted at the Crocker Radiation Laboratory of the University of California. These studies were initiated Oct. 15, 1942, and are continuing at the present time. An extensive survey has been made of the metabolism of twenty different radio-elements. This project has been carried forward by Dorothy Axelrod, M.A., Asst. Prof. D. H. Copp, M.D., Ph.D., Josephine Crowley, A.B., Harvey Fisher, A.B., Ph.D, Henry Lanz, Jr., A.B., Kenneth G. Scott, A.B., L. Van Middlesworth, Ph.D., and the author. During the early phases of the work, we were fortunate in having the advice and aid of Professors I. L. Chaikoff, D. M. Greenberg, and their associates, who assisted the program materially, particularly in the studies with strontium, barium, and cesium. Also with the group, during the war, were Assoc. Prof. Roy Overstreet and Asst. Prof. Louis Jacobson, whose contributions included the radiochemical preparations necessary for the tracer studies. We acknowledge with gratitude the facilities that were extended to us by Prof. Ernest O. Lawrence to do this work in the Radiation Laboratory, the constant advice and encouragement given to us by Dr. Robert S. Stone and his colleagues of the Health Division in the Plutonium Project, the assistance and counsel from Dean S. L. Warren and his staff, the help of the operating crew of the 60-inch cyclotron for the preparation of most of the radio-elements used in these studies, and the cooperation of Profs. W. M. Latimer, G. T. Seaborg, and their associates in providing certain key radio-elements for these studies, notably neptunium, plutonium, americium, and curium. Introduction and Methods During the early phases of the development of the Plutonium Project, it became apparent that one of the most serious problems to be encountered was the protection of personnel working in this field against the immense quantities of radiation and radioactive materials produced by the chain-reacting pile. The most important hazard that arises from the release of nuclear energy are radiations produced directly from fission and subsequently emitted by the resultant fission products and plutonium. The fission products can produce injury either as an external source of radiation or, if they gain entry into the body, by acting as an internal radioactive poison, quite analogous to radium poisoning. This latter consideration is a major concern, since the amounts required within the body to produce injurious effects are minute compared to the quantities necessary to induce damage by external beta and gamma irradiation. A comparison with the history of the radium industry gives an index of the magnitude of the problem presented by fission products and plutonium to the medical protection program of the Plutonium Project.