Direct Electronuclear Production of Tc-99m Precursor at the BTF

The experimental setup used at the BTF that contains the Molybdenum target

In the framework of a scientific collaboration with INFN-LNF (BTF, FISMEL, and SPCM teams), researchers from the Rutherford Appleton Laboratory (RAL, UK) and ENEA explored an alternative approach to produce Tc-99m radiopharmaceutical, a crucial diagnostic tool in medical imaging, without relying on nuclear reactors.

The team has successfully used a dedicated high energy electrons beam from BTF  (E=504 MeV) on a specially designed target by RAL and setup by BTF and SPCM, to investigate the feasibility of direct electronuclear production. A preliminary target solution, consisting of a cascade of very thin foils made of natural Molybdenum, was irradiated in the BTF on March 27-28, 2023 by FISMEL direct supervision, and measured by FISMEL itself in the days after. Gamma spectroscopy was used to measure the radionuclides produced and their activity, which are currently compared to the updated MC predictions, using the real exposure data acquired during the beamtime.

The preliminary results confirm the success of the feasibility study. Moving forward, the team will focus on designing a well-optimized target made of Mo-100 enriched to maximize the Mo-99 activity, building upon the positive outcomes of this study.

Furthermore, the experimental setup enabled the measurement of the Mo-100(e, e’n)Mo99 cross section at 504 MeV, providing valuable input to the assessment of the physical model used in the Monte Carlo code.

Compared to the photonuclear method, where electrons are used to produce bremsstrahlung photons, this direct electronuclear production method should offer several advantages, including reduced harsh environmental dose and reduced spurious secondary RN produced. Furthermore, this method promises to be more suitable to match a new paradigm proposed to produce Mo-99 in a post-pandemic scenario, as reported in the correspondence of Nature | Vol 603 | 17 March 2022 | 393. In particular, the investigated method can potentially improve the post-process of extraction of Mo-99 from thin irradiated according to the specific needs of a hospital, matching the modularity and proximity criteria of the new paradigm. These results provide promising evidence for the potential of direct electronuclear production as a viable alternative for the production of the Tc-99m radiopharmaceutical.

The recent results obtained in BTF could have the potentiality of a critical development for modern medical imaging for a worldwide benefit.