Tissue-specific range uncertainty estimation in proton therapy

Casper Dueholm Vestergaard*, Ludvig Paul Muren, Ulrik Vindelev Elstrom, Jacob Graversen Johansen, Vicki Trier Taasti

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review

Abstract

Background and Purpose: Proton therapy is sensitive to range uncertainties, which typically are accounted for by margins or robust optimization, based on tissue-independent uncertainties. However, range uncertainties have been shown to depend on the specific tissues traversed. The aim of this study was to investigate the differences between range margins based on stopping power ratio (SPR) uncertainties which were tissue-specific (applied voxel-wise) or fixed (tissue-independent or composite).Materials and Methods: Uncertainties originating from imaging, computed tomography (CT) number estimation, and SPR estimation were calculated for low-, medium-, and high-density tissues to quantify the tissue-specific SPR uncertainties. Four clinical treatment plans (four different tumor sites) were created and recomputed after applying either tissue-specific or fixed SPR uncertainties. Plans with tissue-specific and fixed uncertainties were compared, based on dose-volume-histogram parameters for both targets and organs-at-risk.Results: The total SPR uncertainties were 7.0% for low-, 1.0% for medium-, and 1.3% for high-density tissues. Differences between the proton plans with tissue-specific and fixed uncertainties were mainly found in the vi-cinity of the target. Composite uncertainties were found to capture the tissue-specific uncertainties more accu-rately than the tissue-independent uncertainties.Conclusion: Different SPR uncertainties were found for low-, medium-, and high-density tissues indicating that range margins based on tissue-specific uncertainties may be more exact than the standard approach of using tissue-independent uncertainties. Differences between applying tissue-specific and fixed uncertainties were found, however, a fixed uncertainty might still be sufficient, but with a magnitude that depends on the body region.
Original languageEnglish
Article number100441
Number of pages7
JournalPhysics & Imaging in Radiation Oncology
Volume26
Issue number1
Early online date1 Apr 2023
DOIs
Publication statusPublished - 1 Apr 2023

Keywords

  • Proton range uncertainty
  • Proton therapy
  • Treatment planning
  • Patient specific range uncertainty
  • DUAL-ENERGY CT
  • STOPPING-POWER PREDICTION
  • COMPREHENSIVE ANALYSIS
  • DOSE CALCULATION

Fingerprint

Dive into the research topics of 'Tissue-specific range uncertainty estimation in proton therapy'. Together they form a unique fingerprint.

Cite this