14 MeV Neutrons for 99Mo/99mTc Production: Experiments, Simulations and Perspectives

Abstract

Background: the gamma-emitting radionuclide Technetium-99m (^99mTc) 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. ^99mTc is obtained from ⁹⁹Mo/^99mTc generators as pertechnetate ion, which is the ubiquitous starting material for the preparation of ^99mTc radiopharmaceuticals. ⁹⁹Mo in such generators is currently produced in nuclear fission reactors as a by-product of ²³⁵U fission. Here we investigated an alternative route for the production of ⁹⁹Mo 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 ^99mTc-pertechnetate was carried out by means of solvent extraction. Monte Carlo simulations allowed reliable predictions of ⁹⁹Mo 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 10¹⁵ s⁻¹, may potentially supply an appreciable fraction of the current ⁹⁹Mo 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 ⁹⁹Mo.