Experimental and computational studies for an Accelerator-Based Boron Neutron Capture Therapy clinical facility: a multidisciplinary approach

The work described in this thesis has been carried out in the field of AB-BNCT, Accelerator-Based Boron Neutron Capture Therapy. BNCT is a binary radiotherapy combining the enrichment of tumour with boron-10 and its subsequent irradiation with low energy neutrons, exploiting the high cross section of neutron capture in boron-10. With a selective accumulation of boron-10 in the tumour by a suitable borated drug, the products of the reaction release a therapeutic dose in the tumour while sparing the surrounding healthy tissues. This biological selectivity makes BNCT a promising therapy for the treatment of diffuse, infiltrated or metastatic tumors. Recently, the possibility to obtain suitable neutron beams from accelerators has opened a new frontier: AB-BNCT could now become accessible in many hospitals, with improvements in quality of life and clinical outcome for several patients. The context of this work is the design of a clinical BNCT facility based on a Radio Frequency Quadrupole proton accelerator, manufactured by the Italian National Institute of Nuclear Physics (INFN). Such machine can provide a neutron beam suitable for the treatment of deep-seated tumors when coupled to a beryllium target and a Beam Shaping Assembly whose main constituent is solid lithiated aluminum fluoride. Alliflu, densified lithiated aluminum fluoride, is a new material created on purpose at the University and INFN of Pavia through an innovative sintering process on powders of lithium and aluminum fluoride. The work here presented aimed to cover different aspects from the installation of the facility to its clinical applications, and is characterized by a multidisciplinary approach: it includes studies in the field of material science and engineering for the production and analysis of the new material, computational and experimental nuclear physics for the validation of its moderation properties, radiation protection evaluations for the design of an optimized treatment room, and finally a medical physics application consisting in the treatment planning of a realistic clinical case. This work presents a contribution to the implementation of a AB-BNCT facility, demonstrating that R&D has great potential to optimize BNCT quality and to promote a new era of clinical applications.