Highly enriched uranium (HEU) is used to manufacture technetium-99m, the most widely used medical radioisotope in the world. Highly enriched uranium is also used to make nuclear bombs; 50 kg of HEU is enough to make a Hiroshima-type bomb. It is generally agreed that this technology is within the reach of a terrorist group; the main obstacle is acquiring HEU. Currently, as a legacy of the US and Soviet Atoms for Peace Program, there are civilian users of HEU in 40 countries, and about 1,000 kg are still being shipped each year. Unfortunately, the major international manufacturers of technetium-99m have been refusing to convert their production facilities to use low-enriched uranium (LEU), which cannot be used to make a nuclear bomb. Only 1% to 2% of the HEU is consumed in the process of producing technetium-99m. The remainder is accumulating in radioactive waste storage facilities. The radiologic and nuclear medical communities could make a tremendous contribution to a safer world by supporting the replacement of HEU with LEU in the production of technetium-99m. Low-enriched uranium is just as cost effective as HEU for the manufacture of technetium-99m and does not contribute to the risk for nuclear terrorism.