14 MeV Neutrons for 99 Mo/ 99m Tc Production: Experiments, Simulations and Perspectives.

Background: the gamma-emitting radionuclide Technetium-99m (Tc-99m) is still the workhorse of Single Photon Emission Computed Tomography (SPECT) as it is used worldwide for the diagnosis of a variety of phatological conditions. Tc-99m is obtained from Mo-99/Tc-99m generators as pertechnetate ion, which is the ubiquitous starting material for the preparation of Tc-99m radiopharmaceuticals. Mo-99 in such generators is currently produced in nuclear fission reactors as a by-product of U-235 fission. Here we investigated an alternative route for the production of Mo-99 by irradiating a natural metallic molybdenum powder using a 14-MeV accelerator-driven neutron source. Methods: after irradiation, an efficient isolation and purification of the final Tc-99m-pertechnetate was carried out by means of solvent extraction. Monte Carlo simulations allowed reliable predictions of Mo-99 production rates for a newly designed 14-MeV neutron source (New Sorgentina Fusion Source). Results: in traceable metrological conditions, a level of radionuclidic purity consistent with accepted pharmaceutical quality standards, was achieved. Conclusions: we showed that this source, featuring a nominal neutron emission rate of about 10(15) s(-1), may potentially supply an appreciable fraction of the current Mo-99 global demand. This study highlights that a robust and viable solution, alternative to nuclear fission reactors, can be accomplished to secure the long-term supply of Mo-99.