Evaluation of the effective dose during PBFT for brain cancer: A Monte Carlo Study

Introduction: Recently, an approach exploiting the proton therapy biological enhancement by using Boron atoms injected inside a tumor, has been proposed. Three alpha particles with an average energy around 4MeV are emitted from the point of reaction between a proton and boron. In addition, the 719 keV prompt gamma emitted by the proton Boron fusion reactions can be used for on-line proton beam imaging purposes. Materials and Methods: We simulated a proton beam passing through the Snyder head phantom with and without a boron uptake region (BUR) in the tumor to investigate the amplification of the proton’s maximum dose level using a Monte Carlo simulation. The proton’s maximum dose level obtained for different proton energies with considering distinction physical conditions (i.e. location and thickness of BUR, boron concentration). The percentage depth dose (PDD) of the proton in the Snyder phantom without the BUR obtained using the F6 tally. However, the counting of additional proton by alpha particle is based on the results by using F4 tally. The absorbed dose due to three alpha particle and proton components acquired for scalp, skull, tumor and brain. Results: The aim of this study is to compare the effectiveness between proton boron fusion therapy (PBFT) and proton therapy and to analyze dose escalation using a Monte Carlo simulation in the brain cancer. When the portion of the proton’s maximum dose (Bragg- peak) is included at tumor region, which is BUR, observed a dramatic therapy effect with less damage to normal tissue. The peak value of maximum dose level when the boron particle was accurately labeled at the region was 185% among the energies. Conclusion: The PDD of the proton beam from the Snyder phantom including the BURs shows more efficient than that of conventional proton therapy on tumor region. The utility of PBFT was verified using the simulation and it has a potential for application in radiotherapy. When the portion of the proton’s maximum dose (Bragg-peak) is included at tumor region, which is BUR, observed a dramatic therapy effect with less damage to normal tissue.