Impact of Dose Calculation Accuracy on Inverse Linear Energy Transfer Optimization for Intensity-Modulated Proton Therapy

Authors

Mei Chen
Wenhua Cao
Pablo Yepes
Fada Guan
Falk Poenisch
Cheng Xu
Jiayi Chen
Yupeng Li
Ivan Vazquez
Ming Yang
X Ronald Zhu
Xiaodong Zhang

Publication Date

3-1-2023

Journal

Precision Radiation Oncology

DOI

10.1002/pro6.1179

PMID

40336617

PMCID

PMC11935249

PubMedCentral® Posted Date

12-8-2022

PubMedCentral® Full Text Version

Post-print

Abstract

Objective: To determine the effect of dose calculation accuracy on inverse linear energy transfer (LET) optimization for intensity-modulated proton therapy, and to determine whether adding more beams would improve the plan robustness to different dose calculation engines.

Methods: Two sets of intensity-modulated proton therapy plans using two, four, six, and nine beams were created for 10 prostate cancer patients: one set was optimized with dose constraints (DoseOpt) using the pencil beam (PB) algorithm, and the other set was optimized with additional LET constraints (LETOpt) using the Monte Carlo (MC) algorithm. Dose distributions of DoseOpt plans were then recalculated using the MC algorithm, and the LETOpt plans were recalculated using the PB algorithm. Dosimetric indices of targets and critical organs were compared between the PB and MC algorithms for both sets of plans.

Results: For DoseOpt plans, dose differences between the PB and MC algorithms were minimal. However, the maximum dose differences in LETOpt plans were 11.11% and 15.85% in the dose covering 98% and 2% (D2) of the clinical target volume, respectively. Furthermore, the dose to 1 cc of the bladder differed by 11.42 Gy (relative biological effectiveness). Adding more beams reduced the discrepancy in target coverage, but the errors in D2 of the structure were increased with the number of beams.

Conclusion: High modulation of LET requires high dose calculation accuracy during the optimization and final dose calculation in the inverse treatment planning for intensity-modulated proton therapy, and adding more beams did not improve the plan robustness to different dose calculation algorithms.

Keywords

dose calculation accuracy, intensity‐modulated proton therapy, inverse optimization, linear energy transfer

Published Open-Access

yes

Recommended Citation

Chen, Mei; Cao, Wenhua; Yepes, Pablo; et al., "Impact of Dose Calculation Accuracy on Inverse Linear Energy Transfer Optimization for Intensity-Modulated Proton Therapy" (2023). Faculty, Staff and Student Publications. 4030.
https://digitalcommons.library.tmc.edu/uthgsbs_docs/4030