Proton-boron fusion reaction for improving protontherapy: a theoretical model for the reaction cross section

GESER, F. A.; VALENTE, M.

Córdoba

Simposio; 14th International Symposium on Radiation Physics; 2018

Therapy with heavy ions, and particularly with protons, is an alternative modality for treatment of cancer. It is aimed at irradiation of in-depth localized tumors, mainly devoted to neck and head treatments. Moreover, it has also proven to be feasible for infant patients[1]. This localized energy deposition is desirable for dose conformation in this cases, and the inverse depth-dose profile (the Bragg curve) is quite ideal. More recently[2,3], an improvement of the technique was proposed, consisting of using the Boron 11 isotope to induce a nuclear reaction called proton-boron fusion (capture). This reaction final state consists of three alpha particles with energies around 4 MeV having high linear energy transfer, and there is a non-negligible probability of emission of a mono-energetic prompt gamma photon. Therefore, dose enhancement together with on-line monitoring of the irradiation process seem feasible. Moreover, the biological dose enhancement (higher relative biological effectiveness) has already been measured experimentally[4], although the reasons are not very well understood yet.This work proposes a theoretical estimation for the cross section of the proton-boron fusion reaction, based on nuclear theories for isolated resonances and continuum reactions cross sections, which might help to analytically deconvolute the alpha particles contribution from the total dose in the mixed field.[1] Vogel, J. et.al​. Pediatric blood & cancer,​ 65(2), ​2018[2] Do-Kun Yoon et.al. ​Applied Physics Letters​, 105(12), ​2014[3] Han-Back Shin et.al. ​Physica Medica​, 32(10), ​2016[4] Cirrone, G.A.P. et.al. ​Nature, Scientific Reports​, 8(1), ​2018