Optimization of a therapeutic laser accelerated proton beam at 94.8 MeV for Stereotactic Radiosurgery

Abstract

Recent advances in laser-accelerated proton technology have unveiled potential applications for Stereotactic Radiosurgery. In this study, we present a beamline simulation designed by TraceWin and SRIM codes to optimize the spectral and spatial properties of a laser-driven proton beam. The simulation incorporates four quadrupoles for beam focusing, an energy selection aperture aided by a cylindrical on-axis absorber, a scatterer, and an angular selection aperture for energy smoothing and collimation. By optimizing the beamline configuration, we have achieved a uniform beam with dose rates surpassing even those utilized in FLASH radiotherapy, allowing the delivery of high doses to millimeter-scale volumes within nanosecond timescales. To validate the efficacy of our beamline for therapeutic applications of radiosurgery, we conducted another comprehensive simulation study on the irradiation of a hypothetical tumor in a head phantom using Geant4 and FLUKA Monte Carlo-based codes. The results demonstrate that the downstream protons exhibit a narrow energy spread of 94.8 ± 3.9 MeV and a homogenized lateral profile with a possible proton dose of 0.022 J/kg at the center of the tumor. The study also included the Boron dose enhancement and secondary radiation environment. By leveraging laser-accelerated protons instead of cyclotrons, our unique platform offers a precise and relatively cost-effective infrastructure for a laser-accelerated proton beam Stereotactic Radiosurgery.