Titolo della tesi: Theranostic β-emitters production by thermal neutron spectrum reactors: the case of 161Tb at ENEA TRIGA RC-1, Italy
In recent years, the decommissioning of major nuclear facilities dedicated to medical radionuclide production has posed significant challenges to the fields of diagnostic imaging and radiotherapy. This situation has prompted extensive research and development efforts to identify new sources of supply and alternative production methods for these radionuclides. Such initiatives are essential for ensuring the continuity of medical applications, enhancing national self-sufficiency, and minimizing the risks of supply disruptions, ultimately contributing to a more effective and sustainable healthcare.
This thesis work fits within this framework, in collaboration with the ENEA Casaccia Research Center, which has been involved in SECURE, an EU-funded project (HORIZON-EURATOM-2021-NRT-01 call, Strengthening the European Chain of sUpply for next generation medical RadionuclidEs, October 2022 – September 2025).
The project aimed to investigate the feasibility of local radionuclide production for medical applications within Europe, considering both currently established practices
and innovative approaches.
Specifically, it has been investigated the potential option to produce terbium-161 (161Tb), an isotope that shows to be promising for targeted radionuclide therapy and may offer advantages over lutetium-177 (177Lu), which is currently used in cancer treatment.
The method used for the production of 161Tb is the neutron activation technique, exploiting the reaction channel 160Gd(n,γ)161Gd(β−)161Tb.
The use of a gadolinium target highly enriched (over 98%) in gadolinium-160 (160Gd) is necessary to overcome the limitations in chemical and radiochemical purity typically observed in the final product.
In addition, the need to irradiate large quantities of material arise from the low activity concentration generally achievable when the target is irradiated in a research
reactor, i.e. in a lower neutron fluence rate magnitude condition with respect to production reactors established today. Enrichment also facilitate the chemical processing of the irradiated target, which involves the extraction and purification of both 161Tb -the radionuclide precursor used in radiopharmaceuticals preparation for cancer therapy- and 160Gd oxide, which can be recovered and reused in subsequent irradiation cycles.
Finally, an economic evaluation of the entire process was also carried out, and preliminary outcomes from the ENEA team developing the specialized chemical technique for processing the irradiated target are presented.
In conclusion, this work not only contributes to the scientific understanding of terbium-161 production through neutron activation in a medium-scale research reactor, but also highlights the strategic importance of developing autonomous and sustainable medical radionuclide supply chains within European countries. By combining technological innovation, economic assessment, and collaboration between research institutions, this study reinforces the vision of a resilient nuclear medicine ecosystem.