A Monte Carlo study of high-LET particle production in proton boron therapy

Abstract

We simulate the production of high-LET particles from different boron nuclear reactions in proton therapy. This study is motivated by neutron capture-enhanced particle therapy (NCEPT) (Safavi-Naeini et al. in Sci Rep 8(1):1–13, 2018) and the recently proposed proton boron capture therapy (PBCT) (Cirrone et al. in Sci Rep 8(1):1–15, 2018), where both therapy types suggest to utilize the production of high-LET particle for enhancing the RBE of the treatment. From Monte Carlo simulations performed in TOPAS (Perl et al. in Med Phys 39(11):6818–6837, 2012), we find that NCEPT reaction is the more prominent reaction of the two with a factor of 4000 pm 700 more particles produced. The reason for this is the relative high fluence of thermal and epithermal neutrons (neutrons < 1 hbox { keV}) present in clinical relevant proton fields. The creation of these neutrons is shown to be highly influenced by the target phantom and proton field size. By varying the field and phantom size, it was found that the fluence of low-energy neutrons can increase/decrease two orders of magnitude.