Joseph Gilbert Hamilton (11 November 1907 – 18 February 1957) was an American professor of Medical Physics, Experimental Medicine, General Medicine, and Experimental Radiology as well as director (1948-1957) of the Crocker Laboratory, part of the Lawrence Berkeley National Laboratory. Hamilton studied the medical effects of exposure to radioactive isotopes and he pioneered their use in the treatment and diagnosis of disease. He was married with the painter Leah Hamilton.
Hamilton received his B.S. in Chemistry in 1929 from the University of California. He studied medicine in Berkeley, and he interned at the University of California Hospital, San Francisco. He was awarded his M.D. degree in 1936. The cyclotron in Berkeley was then producing useful amounts of radioactive isotopes, and even before he received his degree, Hamilton became interested in their effects on living tissue. In a series of papers published in 1937 he detailed early medical trials using radiosodium, followed by papers detailing the use of the radioactive isotopes of potassium, chlorine, bromine, and iodine. Radioactive iodine was found to be particularly useful in the diagnosis and treatment of thyroid disorders.
Hamilton’s studies of isotope retention in humans, especially of radioactive strontium and the transuranic elements, were the principal source for the U.S. Atomic Energy Commission’s estimates of tolerance limits of these substances. As part of the Manhattan Project in 1944 he and his research team began studies on the effect of plutonium on humans. In trials conducted 1945-1946, plutonium was injected in humans both healthy and those with cancer. The trials were terminated by the Atomic Energy Commission in 1950.
Hamilton died at the age of 49 of radiation induced leukemia.