Joseph Gilbert Hamilton, Medicine; Medical Physics: San Francisco and Berkeley
Joseph Gilbert Hamilton was born on November 11, 1907, the son of Gilbert and Mary Hamilton. After early schooling in Santa Barbara, he entered the University of California's College of Chemistry in 1925, receiving the B.S. degree in 1929. This thorough training in chemistry profoundly influenced his later work. Following his medical studies in Berkeley and San Francisco, he interned at the U.C. Hospital, demonstrating special interest in neuropsychiatry. He was awarded the M.D. degree in 1936. The cyclotron in Berkeley was then producing the first useful amounts of radioactive isotopes, and Dr. Hamilton immediately became interested in their application to medical research. In 1936 he made the first observations on the rapid absorption and distribution of millicurie amounts of ingested radiosodium, Na24, in man; one of the subjects was “J. G. H.” The results were reported in a series of papers in 1937, followed by similar observations using newly available radioactive isotopes of potassium, chlorine, bromine, and iodine. He promptly recognized the possibility of using the selective iodine uptake of the thyroid to measure glandular function, using larger doses to irradiate the gland for suppression of hyperactive states. Widespread use of radioactive iodine for the diagnosis and treatment of thyroid disorders ― 28 ―
followed. An interesting sequel came in 1940 when Corson, McKenzie, and Segrè discovered element 85, astatine, the element
homologous to and heavier than iodine in the halogen family. From his knowledge of chemistry and physiology, Dr. Hamilton
conjectured that astatine would be preferentially absorbed by the thyroid. Concurrent with the discoverers' determination
of the chemical and physical properties which established the isotope as 85, he showed that this α-emitting isotope, 85At211,
was preferentially absorbed in thyroid tissue. Exposure to astatine has been one of the major tools in the study of α-radiation.
During these years prior to World War II, Dr. Hamilton participated widely in academic affairs and rose from Assistant in Neuropsychiatry to Clinical Instructor in Neurology. In 1942 he was appointed Assistant Professor of Medicine and Radiology in the School of Medicine. Meanwhile, he also held an appointment in the Radiation Laboratory as Research Fellow and then Research Associate. The war brought new and increased responsibilities. The physicists in charge of the 60-inch cyclotron in Crocker Laboratory were recruited for radar and Manhattan Project work. With his characteristic energy, and fascinated by nuclear research, he undertook to supervise operation of the cyclotron as well as much of the research to which it led. The position as Director of the Crocker Laboratory, to which he was appointed in 1948, he held until his death. In this period, the energy of the 60-inch cyclotron was raised twice, from 16 to 20 to 24 Mev for deuterons, maintaining the useful current of particles at high levels. He participated actively in the redesign and was a stimulating leader to the operating crew. His extensive published notes on yields from nuclear reactions disclose keen appreciation of the technical problems of cyclotron operation. In the years following 1941, the Manhattan Project urgently ― 29 ―
needed information on the metabolism and effects of ingested plutonium and fission products. Dr. Hamilton and his co-workers
in the Crocker Laboratory poured forth a steady stream of research on the preparation of carrier-free radioactive isotopes
and the biological effects of their ingestion. He was one of the first to show the physiological differences between carrier-free
amounts and macroscopic quantities of an element. He was keenly aware that the biologic problems arising from fission product
contamination needed to be anticipated; this was his dedicated lifework. Throughout the first decade of the atomic age, his
studies of isotope retention, especially of radioactive strontium and the transuranic elements, constituted the principal
source for estimation of tolerance limits of these substances. His pioneer development of radioautography, in which a photographic
film in contact with a tissue section registers the pattern of radioactive atoms present, was instrumental in predicting the
toxicity of the specifically localized bone-seeking isotopes and has also contributed to understanding of the mode of bone
formation. Radioautography now has wide application in biology and technology. In addition to his work on metabolism of elements,
Dr. Hamilton had begun experimental irradiation of organic liquids by heavy particles, an important addition to knowledge
of radiation effects.
In 1945 Dr. Hamilton was appointed Assistant Professor of Medical Physics in the newly formed Medical Physics division of the Department of Physics, advancing in 1946 to Associate Professor and in 1950 to Professor, with corresponding promotions in the School of Medicine to Associate Professor and Professor of Radiology and Experimental Medicine. He traveled extensively in this country and in Europe to attend scientific meetings. He was a member of Tau Beta Pi, Sigma Xi, Alpha Chi Sigma, American Federation for Clinical Research, American Society for Clinical Investigation, ― 30 ―
American Physical Society, Society for Experimental Biology and Medicine, and Fellow of the American Physiology Society.
Dr. Hamilton learned that he was suffering from leukemia in 1955. In spite of weakness and poor health, he kept up his interest and activities in Crocker Laboratory. While he had cautioned others against excessive irradiation, his own life was filled with episodes resulting in exposure that undoubtedly contributed to his illness. He died on February 18, 1957. He is survived by his wife, Leah Rinne Hamilton, whom he had helped through illness and who quietly but courageously helped him in his last illness. Dr. Hamilton participated in the first applications of radioactive isotopes to problems of our age. His pioneer contributions will remain significant, for they anticipated discoveries now being made in this full-bodied field of science. More important to those who knew him was his helpful enthusiasm, his willingness to share his time and facilities with those in need of help, his loyalty to his co-workers, and his devotion to science.
A. C. Helmholz
C. W. Asling
H. B. Jones
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