Solid targets for 99m Tc production on medical cyclotrons

Recent disruptions in the molybdenum-technetium generator supply chain prompted a review of non-reactor based production methods for both 99 Mo and 99m Tc. Small medical cyclotrons ( E p ~ 16–24 MeV) are capable of producing Curie quantities of 99m Tc from isotopically enriched 100 Mo using the 100 Mo(p,2n) 99m Tc reaction. Unlike most other metallic target materials for routine production of medical radioisotopes, molybdenum cannot be deposited by reductive electroplating from aqueous salt solutions. To overcome this issue, we developed a new process for solid molybdenum targets based on the electrophoretic deposition of fine 100 Mo powder onto a tantalum plate, followed by high temperature sintering. The targets obtained were mechanically robust and thermally stable when irradiated with protons at high power density.