Processing and Evaluation of Linear Accelerator-Produced Mo99-Tc99m

We are developing electron linear accelerator 100Mo(γ,n)99Mo technology as a replacement to nuclear reactor 235U(n,f)99Mo production. We report irradiation of natural molybdenum disks (25MeV, 10kW) and 100Mo-enriched disks (35MeV, 2kW), their dissolution and the extraction of 99mTc-pertechnetate. Up to 6.2GBq 99Mo was produced, solvent extraction was performed at >90% yields of 99mTc, and quality control showed that a product with high radionuclidic and radiochemical purity could be obtained. Irradiated natural molybdenum products showed more impurities (Nb91m, Nb92m, Nb95m and Nb95) than enriched target material. Linear accelerator technology is feasible for production of quality 99Mo/ 99mTc, particularly when paired with 100Mo enriched targets.

The radioisotope technetium-99m is the most widely used worldwide in diagnostic nuclear medicine, thanks to its near-optimal characteristics (short half life [T1/2 = 6.01 H], low-energy γ emission [Eγ= 140 keV], versatile chemistry, and relatively low cost). It is used in about 80% of medical diagnosis imaging procedures to detect and monitor pathologies of diverse physiological conditions such as myocardial perfusion, kidney disorders and bone metastases [1]. 99mTc is -decay of its parent molybdenum-99 (half life = 66.02 H). Prior to 2010, 75 % of the world’s supply of 99Mo was produced from the National Research Universal (NRU) reactor in Chalk River, Canada and the High Flux Reactor (HFR) in Petten, Netherlands. These reactors are over 50 years old and use highly enriched uranium (HEU), typically greater that 85% 235U, in a neutron-induced fission process for production of 99Mo. The advanced age led to a number of recent critical shutdowns, most notably in 2009-2010 that affected both reactors [2-4]. In addition, HEU use and the highly radioactive waste generated are major proliferation and security concerns in the use of reactors for medical isotope production [5]. The age-related N generator, and on quality control evaluations of the 99Mo and 99mTc products. Irradiations during this period were performed at two available sites with different linear accelerator configurations; at Mevex Corporation and at the National Research Centre. These accelerators were used pending the installation and commissioning of an electron linear accelerator at the Canadian Light Source that will be primarily dedicated to 100Mo(,n)99Mo isotope production. The solvent extraction technology deployed to the project had previously been utilized at the Health Sciences Centre for routine clinical 99Mo/99mTc separations of fission-reactor produced 99Mo [13].