RBE Model-Based Biological Dose Optimization for Proton Radiobiology Studies

Abstract Purpose: The purpose of the current study was (1) to develop a straightforward and rapid method to incorporate a dose-averaged linear energy transfer (LETd)–based biological effect model into a dose optimization algorithm for scanned protons; and (2) to apply a novel beam delivery strategy with increased LETd within the target, thereby enhancing the biological effect predicted using the selected relative biological effectiveness (RBE) model. Materials and Methods: We first generated pristine dose Bragg curves in water and their corresponding LETd distributions for 94 groups of proton beams, using experimentally validated Geant4 Monte Carlo simulations. Next, we developed 1-dimensional dose optimization algorithms by using the Python programming language. To calculate the RBE of protons for biological dose optimization, we invoked the McNamara RBE model and applied the radiobiological parameters of the lung cancer H460 cell line with 137Cs reference photons. Results: High-accuracy optimization res...