Double scattering and pencil beam scanning Monte Carlo workflows for proton therapy retrospective studies on radiation-induced toxicities

A M M Leite; A Bonfrate; A Da Fonseca; P Lansonneur; C Alapetite; H Mammar; L De Marzi

doi:10.1016/j.canrad.2023.02.001

Double scattering and pencil beam scanning Monte Carlo workflows for proton therapy retrospective studies on radiation-induced toxicities

Cancer Radiother. 2023 Jun;27(4):319-327. doi: 10.1016/j.canrad.2023.02.001. Epub 2023 May 8.

Authors

A M M Leite¹, A Bonfrate², A Da Fonseca², P Lansonneur², C Alapetite², H Mammar², L De Marzi³

Affiliations

¹ Inserm U 1021- CNRS UMR 3347, Institut Curie, PSL Research University, University Paris Saclay, 91898, Orsay, France; Institut Curie, PSL Research University, Radiation Oncology Department, Proton Therapy Centre, centre universitaire, 91898 Orsay, France.
² Institut Curie, PSL Research University, Radiation Oncology Department, Proton Therapy Centre, centre universitaire, 91898 Orsay, France.
³ Institut Curie, PSL Research University, Radiation Oncology Department, Proton Therapy Centre, centre universitaire, 91898 Orsay, France; Inserm LITO, Institut Curie, PSL Research University, University Paris Saclay, 91898 Orsay, France. Electronic address: ludovic.demarzi@curie.fr.

PMID: 37164897
DOI: 10.1016/j.canrad.2023.02.001

Abstract

Purpose: Monte Carlo (MC) simulations can be used to accurately simulate dose and linear energy transfers (LET) distributions, thereby allowing for the calculation of the relative biological effectiveness (RBE) of protons. We present hereby the validation and implementation of a workflow for the Monte Carlo modelling of the double scattered and pencil beam scanning proton beamlines at our institution.

Methods: The TOPAS/Geant4 MC model of the clinical nozzle has been comprehensively validated against measurements. The validation also included a comparison between simulated clinical treatment plans for four representative patients and the clinical treatment planning system (TPS). Moreover, an in-house tool implemented in Python was tested to assess the variable RBE-weighted dose in proton plans, which was illustrated for a patient case with a developing radiation-induced toxicity.

Results: The simulated range and modulation width closely matches the measurements. Gamma-indexes (3%/3mm 3D), which compare the TPS and MC computations, showed a passing rate superior to 98%. The calculated RBE-weighted dose presented a slight increase at the necrosis location, within the PTV margins. This indicates the need for reporting on the physical and biological effects of irradiation in high dose regions, especially at the healthy tissues and increased LET distributions location.

Conclusion: The results demonstrate that the Monte Carlo method can be used to independently validate a TPS calculation, and to estimate LET distributions. The features of the in-house tool can be used to correlate LET and RBE-weighted dose distributions with the incidence of radiation-induced toxicities following proton therapy treatments.

Keywords: Efficacité biologique relative; Monte Carlo simulations; Proton therapy; Protonthérapie; Radiation-induced toxicities; Relative biological effectiveness; Simulations Monte Carlo; Toxicités radio-induites.

MeSH terms

Algorithms
Humans
Monte Carlo Method
Proton Therapy* / adverse effects
Proton Therapy* / methods
Protons
Radiation Injuries*
Radiotherapy Dosage
Radiotherapy Planning, Computer-Assisted / methods
Retrospective Studies
Workflow

Substances

Protons