Physics-related epistemic uncertainties in proton depth dose simulation

TL;DR

This paper evaluates physics models and their epistemic uncertainties in proton dose simulations using Geant4, highlighting their impact on radiotherapy applications and guiding future experimental efforts.

Contribution

It systematically assesses epistemic uncertainties in proton energy deposition models within Geant4, providing quantitative guidance for their use in radiotherapy simulations.

Findings

Identified key sources of epistemic uncertainties affecting proton dose simulations.

Quantified the impact of model uncertainties on simulation accuracy.

Provided recommendations for experimental measurements to reduce uncertainties.

Abstract

A set of physics models and parameters pertaining to the simulation of proton energy deposition in matter are evaluated in the energy range up to approximately 65 MeV, based on their implementations in the Geant4 toolkit. The analysis assesses several features of the models and the impact of their associated epistemic uncertainties, i.e. uncertainties due to lack of knowledge, on the simulation results. Possible systematic effects deriving from uncertainties of this kind are highlighted; their relevance in relation to the application environment and different experimental requirements are discussed, with emphasis on the simulation of radiotherapy set-ups. By documenting quantitatively the features of a wide set of simulation models and the related intrinsic uncertainties affecting the simulation results, this analysis provides guidance regarding the use of the concerned simulation tools in experimental applications; it also provides indications for further experimental measurements addressing the sources of such uncertainties.