Implementation of Multi-Curie Production of 99mTc by Conventional Medical Cyclotrons

Tc-99m is currently produced by an aging fleet of nuclear reactors, which require enriched uranium and generate nuclear waste. We report the development of a comprehensive solution to produce Tc-99m in sufficient quantities to supply a large urban area using a single medical cyclotron. Methods: A new target system was designed for Tc-99m production. Target plates made of tantalum were coated with a layer of Mo-100 by electrophoretic deposition followed by high-temperature sintering. The targets were irradiated with 18-MeV protons for up to 6 h, using a medical cyclotron. The targets were automatically retrieved and dissolved in 30% H2O2. Tc-99m was purified by solid-phase extraction or biphasic exchange chromatography. Results: Between 1.04 and 1.5 g of Mo-100 were deposited on the tantalum plates. After high-temperature sintering, the Mo-100 formed a hard, adherent layer that bonded well with the backing surface. The targets were irradiated for 1-6.9 h at 20-240 mu A of proton beam current, producing up to 348 GBq (9.4 Ci) of Tc-99m. The resulting pertechnetate passed all standard quality control procedures and could be used to reconstitute typical anionic, cationic, and neutral technetium radiopharmaceutical kits. Conclusion: The direct production of Tc-99m via proton bombardment of Mo-100 can be practically achieved in high yields using conventional medical cyclotrons. With some modifications of existing cyclotron infrastructure, this approach can be used to implement a decentralized medical isotope production model. This method eliminates the need for enriched uranium and the radioactive waste associated with the processing of uranium targets.