As soon as the capability to produce radioactive atoms was achieved in the 1930s, physician-scientists gravitated as apprentices toward important research centers, such as those at Berkeley, Washington University, and Massachusetts Institute of Technology (M.I.T.)/Massachusetts General Hospital. After World War II, Oak Ridge Associated Universities (ORAU) trained many of the founders of the specialty of nuclear medicine. The initial ORAU preparatory course lasted only 3 weeks. Over the 20 years after World War II, only 100 to 200 physicians had learned radioisotopic techniques and their clinical applications from their older preceptors. The founding of the conjoint American Board of Nuclear Medicine in 1971 (cosponsored by the American Boards of Internal Medicine, Pathology, and Radiology) marked a new era in certifying the quality of graduates of a growing number of nuclear medicine residency programs. Future trends in nuclear medicine education include the following: greater availability of jobs for physicians with board certification in radiology and nuclear medicine; an increased emphasis on training in positron-emission tomography (PET); and recertification and documentation of maintenance of professional competence as certainties.