On the (un)effectiveness of proton boron capture in proton therapy

Abstract

We present calculations and simulations on the role of the p+ 11 B→3α reaction in proton therapy. This reaction has been recently suggested to be responsible for a decrease in the survival probability of tumor cells, when they are irradiated with low-energy protons. However, at the concentration levels typical of the proposed boron carrier (sodium borocaptate, Na 2 B 12 H 11 SH, in short BSH), i.e. less than 100 ppm, both calculations and Monte Carlo simulations suggest that the dose related to this reaction is orders of magnitude lower than the dose delivered by the primary proton beam inside the tissues. These calculations cast some doubts on the claim of an important role played by Proton Boron Capture in enhancing the therapeutic effectiveness of proton therapy, and suggest that other mechanisms should be investigated in order to explain the observed decrease in the survival probability.

Enhancement of Radiation Effectiveness in Proton Therapy: Comparison Between Fusion and Fission Methods and Further Approaches

“…As it is shown, the tumor with 1.4 cm of diameter has been treated by the proton beam with spread energy from 45 MeV to 60 MeV for low depth position (SOBP from 1.6 cm to 3 cm) and 121 MeV to 130 MeV for the deepest position (SOBP from 10 cm to 11.3 cm). The calculated energy ranges and the corresponding Bragg's peaks illustrated in this figure have agreement with the other reported data 25,26,45 . In the following presented results, the Bragg's end position and the corresponding proton energy have been mention to represent the tumor's depth.…”

“…The MC tools, the problem's setup and the process in obtaining of the results have been introduced according to the following subsections: MC Setup. In the present evaluations, for better performance and to obtain the more reliable evaluations, two MC tools have used; MCNPX2.7 and GEANT4.10.5-p02, in which, the MCNPX utilized TENDL 2017 47,48 and GEANT4 also utilized physics lists of QGSP_BIC_HP 44,45 for the both proton and neutrons interactions introduced as follow;…”

“…In this research, the results were based on the using of 100% enriched10 B for NCEPT and 11 B for P-BFT. Also, the mass concentrations of 100 ppm were applied as it is near the concentration of 80 ppm discussed by Cirrone et al19 and Mazzone et al45 and most of the other performed works[3][4][5][6][7][8] . The higher values up to 1000 ppm in this research have been examined for a physical evaluation of the impacts regarding the NCEPT andP-BFT as discussed at the end of the Results and Discussions section.…”

Is the proton–boron fusion therapy effective?

“…In addition, any boron carrier agents such as boronophenylalanine have a small uptake in the tumour. The mentioned in vitro investigation 7 will not be prepared in the current study, because it was prepared by the above-mentioned study, 8 and it has a different structure than our work. However, the first group's results 1,3-5 will only be dealt on to see whether the used 11 B concentration is realistic?…”

“…However, their findings were questioned by Mazzone et al, some months later. 8 Mazzone et al performed some MC calculations by GEANT4 9 and, consequently, indicated that the results cannot demonstrate the dose enhancement for the in vitro setup because the yield of alpha particles is too low to affect the proton therapy dose. In addition, any boron carrier agents such as boronophenylalanine have a small uptake in the tumour.…”