As the U.S. government works to strengthen its global nuclear security strategy by eliminating potential sources of bomb-grade highly enriched uranium (HEU), it has eyed the production of medical isotopes for nuclear imaging, which rely on HEU. To encourage reliable supplies of medical radioisotopes produced from non-HEU sources, President Obama signed into law on Jan. 2, 2013, the American Medical Isotopes Production Act of 2011 (AMIPA). It should be noted that it was part of the 2013 National Defense Authorization Act, so the measure goes beyond interest in just making sure patients have access to radiopharamceutical tracers to enable myocardial perfusion imaging (MPI) scans. The effort is designed to make HEU sources less available on the world market to reduce the threat of nuclear weapons proliferation or the building of a “dirty bomb.”