Radiation protection assessment of patient activation and dosimetry in Boron Neutron Capture Therapy

Boron Neutron Capture Therapy (BNCT) is a form of radiotherapy based on the irradiation of the tumor with a low energy neutron beam, after the administration of a selective drug enriched in boron-10. The therapy exploits the high cross section of thermal neutron capture in boron, generating two low-range charged particles. The availability of accelerators able to generate high-intensity neutron beams via proton nuclear interaction is boosting the construction of new clinical centers. One of these is under development in Italy, using a 5 MeV, 30 mA proton radiofrequency accelerator coupled to a beryllium target, funded by the Complementary Plan to the Recovery and Resilience National Plan, under the project ANTHEM. The present study focuses on radiation protection aspects of patients undergoing BNCT, specifically on the activation of their organs and tissues. A criterion to establish the relevance of such activation after BNCT has been proposed. Based on the current Italian regulatory framework, the level of patient activation following BNCT treatment does not pose a significant radiological concern, even shortly after irradiation. Another aspect is the activation of patient’s excretions, which can impact on the design of the building and requires a process for the discharge. The described study contributes to the radiation protection study for the ANTHEM BNCT centre in Italy. • The adult-patient model from ICRP-145 has been used for a benchmark between MCNP and PHITS. • A criterion for patients discharge after BNCT based on Italian regulation in nuclear medicine is proposed. • Activation of patients after BNCT has been studied in different irradiation positions. • Excretes activation has been evaluated. • Activation studies are pivotal in the BNCT facility design and management.