Isotope production and distribution have been part of DOE's mission since at least 1954, when the Atomic Energy Act of 1954 specified the role of the U.S. government in isotope distribution. DOE's Isotope Program fills this role by providing isotopes to support the national and international need for a reliable supply for use in medicine, industry, and research. The Isotope Program provides both radioactive isotopes, called radioisotopes, and stable isotopes, which are not radioactive.