Thermal cross-sections of organic materials for neutron capture therapy.
Romanelli G., Andreani C., Preziosi E., Senesi R.
Neutron capture therapy allows cancer treatment based on body irradiation by neutrons and their capture by a specific isotope within a carrier targeting the tumour. Epithermal neutrons ensure high penetration power in the body, yet the absorption is favoured at low neutron energies. The required moderation, ensured by the scattering from hydrogen within the body, depends on the physical/chemical properties of organic molecules therein. We present a phenomenological approach, based on neutron transmission experiments and $ab initio$ phonon calculations, to model the total scattering cross-section of organic molecules based on the Average Functional Group Approximation. Results are discussed in the case of proteins, human tissue, and polymers often used as phantom materials in Monte Carlo simulations for hadron therapy applications. Authors gratefully acknowledge the financial support of the Consiglio Nazionale delle Ricerche -- within CNR-STFC Grant Agreement [2014-2020 (N 3420)] concerning collaboration in scientific research at the ISIS (UK) of STFC -- and of the JRU ISIS@MACH ITALIA, Research Infrastructure hub of ISIS (UK) -- MUR official registry U. 0008642.28-05-2020.