14 MeV neutrons for medical application: a scientific case for 99Mo/99Tcm production

⁹⁹Tc^m is a widely used radionuclide for SPECT (Single Photon Emission Computed Tomography) diagnostics thanks to its short half-life (about 6h) and the low-energy gamma ray emission (140 keV) well suited for diagnostic devices. The specific method for producing ⁹⁹Tc^m via ¹⁰⁰Mo(n,2n)⁹⁹Mo reaction, as it was investigated in ENEA, is discussed in detail in this paper. The ⁹⁹Mo activity achieved by means of 14 MeV neutron irradiation on natural Molybdenum sample irradiated at the Frascati Neutron Generator (FNG) facility, at the Research Centre of ENEA-Frascati, was accurately assessed, by tracing it to the activity standards provided by the Italian National Institute of Ionizing Radiation Metrology (INMRI), located at the Research Centre of ENEA-Casaccia. The whole experiment carried out in ENEA was supported by simulations performed with the Fluka Monte Carlo code, whose predictions have been benchmarked against the experimental data collected at ENEA-FNG, relying on the traceability to the activity standards developed and maintained at the ENEA-INMRI Radioactivity laboratories.