This patent application is for the distributed production of Tc-99m, a radionuclide extensively used in diagnostic medicine. Central to the invention is the generation of high energy gamma rays which can be produced by the interaction of neutrons with various materials of different atomic mass. In the first phase of production Mo-100 is used as a target. Gamma rays greater than 8 MeV are used to remove a neutron from the target material, thereby generating Mo-99, which decays to the desired radionuclide Tc-99m. This is a low yield system which is designed for in situ , on demand production of Tc-99m without the complications of a supply chain. Additionally no highly enriched uranium or low enriched uranium is used in this process.