RESUMEN
The US Transuranium and Uranium Registries is a human tissue program that collects tissues posthumously from former nuclear workers and radiochemically analyzes them for actinides such as plutonium, americium, and uranium. It was established in 1968 with the goal of advancing science and improving the safety of future workers. Roundtable participants recalled various aspects of this multidisciplinary research program, from establishing consistent autopsy protocols to comparing the registries' findings to those of other programs, such as the historical beagle dog studies and the Russian Radiobiological Human Tissue Repository. The importance of meeting ethical and legal requirements, including written consent forms, was emphasized, as was the need to know whether workers were exposed to nonradiological hazards such as beryllium or asbestos. At Rocky Flats, a bioassay program was established to follow workers after they terminated employment. The resulting data continue to help researchers to improve the biokinetic models that are used to estimate intakes and radiation doses. After 50 y, the US Transuranium and Uranium Registries continues to contribute to our understanding of actinides in humans, which is a testament to the vision of its founders, the generosity of its tissue donors, and the many dedicated scientists who have worked together to achieve a common goal.