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.
Highlights
Metastable Technetium-99 (99m Tc) is a well-suited radionuclide for medical imaging thanks to its short half-life [1] T1/2 = 6.0067(10)h [2] and the 140 keV γ-ray emission
Frascati preparation of the Generatorwe (FNG) is an accelerator-driven continuous neutron source which relies on the fusion reaction: D + T → α (3.5 MeV) + n (14.1 MeV)
FNG produces almost monochromatic neutrons with a nominal maximum neutron emission rate of 1011 s−1, well determined by means of an absolute measurement based on the so-called associated alpha particle technique [29]
Summary
Metastable Technetium-99 (99m Tc) is a well-suited radionuclide for medical imaging thanks to its short half-life [1] T1/2 = 6.0067(10)h [2] and the 140 keV γ-ray emission. Molecules 2018, 23, 1872; doi:10.3390/molecules23081872 www.mdpi.com/journal/molecules Molecules 2 of 182 of 19. 99m Tc are used worldwide in Single Photon Emission Computed Tomography, with more based on Metastable. Technetium-99 (99mTc) is a well-suited radionuclide for medical imaging thanks to its than 30 million procedures per year, accounting forkeV about of all nuclear medicine diagnostics short half-life [1] T1/2 = 6.0067(10)h [2] and the 140 γ‐ray emission.
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