Is the proton–boron fusion therapy effective?

Abstract

Introduction: In the recent years, some publications (mainly from one group of authors) have dealt with the effectiveness of proton–boron fusion therapy (PBFT). This theory is based on the Q-value of three produced α particles in the reaction of protons with boron (11B). They claim that this reaction significantly increases the absorbed dose in the target volume. However, the current study would re-evaluate their method to show if PBFT is really effective. Methods and materials: A parallel 80-MeV proton beam was irradiated on a water medium in a cubic boron uptake region (BUR). The two-dimensional dose distribution and percentage depth dose of protons, alphas and all particles were calculated using tally F6 and mesh-tallies by Monte Carlo N Particle Transport code. Results: The results not only showed that the dose enhancement in BUR is neglectable but also the higher density of BUR in comparison with water led to decrement of dose in this region. Because of low cross section of boron for proton beam (<100 mb), the α particles’ dose is 1,000 times lower than the proton dose. Conclusions: The physical aspects and the simulation results did not show any effectiveness of the PBFT for proton therapy dose enhancement.

Effect of boron compounds on the biological effectiveness of proton therapy

“…Our results further confirm previous Monte Carlo simulations indicating that the amount of dose enhancement generated by the proton-boron reaction is negligible. [7][8][9][10][11][12][13] However, our results stand in contrast with the previous work with the same cell line (DU145) and the same concentration of BSH and 11 B. 4,5 In our work, we repeated our experiments a minimum of three times, and most experiments were repeated four or five times.…”

“…Both BSH and BPA solutions were filter-sterilized through 0.22-μm filters and stored in the dark at 4 • C. Filtration did not affect the final concentration of 11 B for the BSH or BPA solutions as verified using inductively coupled plasma optical emission spectroscopy before and after filtration. BSH stock solution was prepared on June 18, 2021 and stored in the dark at 4 • C for the duration of the experiments, which lasted until August 20, 2021.…”

“…BSH treatment modestly radiosensitized DU145 cells exposed to either X-rays or protons (Figure 2). This F I G U R E 7 Data from parameters of survival curves of DU145 cells treated with vehicle (fructose) or 86.9 ppm of 11 B as 4-borono-L-phenylalanine (BPA) and exposed to X-rays, 1.2-keV/μm protons, or 9.9-keV/μm protons extracted from the survival curve data from radiosensitization effect was more pronounced at larger doses (D 50% and D 10% ) than at 2 Gy: at SF 2 Gy , a significant difference was observed only for 9.9-keV/μm protons (Figure 3a), whereas at D 50% and D 10% , significant differences were observed for all radia-tion qualities (Figure 3b,c). The SER at SF 2 Gy for 9.9-keV/μm protons (1.06 ± 0.04 [SD, n = 4]) was slightly but significantly different from that of X-rays (1.01 ± 0.03 [SD, n = 3]) (Figure 3d).…”

The Proton-Boron Reaction Increases the Radiobiological Effectiveness of Clinical Low- and High-Energy Proton Beams: Novel Experimental Evidence and Perspectives

“…It is worth pointing out that all these studies are in silico ones, speculating exclusively on the basis of theoretical calculations and modelling. Moreover, opposed to Ganjeh and Eslami-Kalantari ( 70 ), whose simulations using a phantom model of brain tumor agree with the potential benefits deriving from the p-B reaction, the recurrent criticism put forward by those arguing against the meaningfulness of PBCT is that the increase in the deposited dose within the target volume by the α-particles from the p-B reaction would be negligible, hence insufficient to elicit a measurable, clinically relevant effect ( 68 , 69 ). However, it has been long known that macroscopically absorbed dose is just one factor on which the radiobiological efficiency of ionizing radiation depends; other physical parameters reflecting the inherently inhomogeneous pattern of energy deposition events at the micro- and nanometric scale, such as particle track structure, impact the fate of irradiated cells.…”

“…More importantly, enhancing PT effectiveness could also expand the range of cancers eligible for treatment by PT by including those refractory to CRT. The first, and thus far to the best of the authors' knowledge, only experimental proof by Cirrone et al ( 14) that the p-B reaction can indeed increase the biological effectiveness of a clinical proton beam, has sparked interest on PBCT as demonstrated by recently published studies (66)(67)(68)(69)(70). It is worth pointing out that all these studies are in silico ones, speculating exclusively on the basis of theoretical calculations and modelling.…”