The First Experience of Accelerator-based Lithium Neutron Capture Therapy in vivo

Boron neutron capture therapy (BNCT) is one of the promising treatment methods for cancer. BNCT is based on the unique high ability of the non-radioactive boron-10 (10B) nucleus to absorb thermal neutrons. The absorption of a neutron by boron results in a nuclear reaction 10B(n,)7Li with 84% of the energy being released within the cell, thereby inducing cancer cell death. We propose a novel approach based on using lithium instead of boron in neutron capture therapy: the neutron capture reaction cross-section for lithium is 4 times smaller than that of boron, while the energy release is 2 times higher, and the primary advantage of lithium is that 100% of the energy is released inside the cell. A series of in vivo neutron irradiation experiments using the murine B16 skin melanoma model demonstrated the efficacy of lithium neutron capture therapy (LiNCT). Higher lithium concentrations in the tumor achieved through intraperitoneal administration, compared to the oral route, contributed to a significant increase in animal survival and a significant decrease in tumor growth. The results of our study provide entirely new opportunities for the development of neutron capture therapy, both with lithium and with a possible lithium-boron combination.