Combining inter-observer variability, range and setup uncertainty in a variance-based sensitivity analysis for proton therapy

Jan Hofmaier; Franziska Walter; Indrawati Hadi; Maya Rottler; Rieke von Bestenbostel; George Dedes; Katia Parodi; Maximilian Niyazi; Claus Belka; Florian Kamp

doi:10.1016/j.phro.2021.11.005

Combining inter-observer variability, range and setup uncertainty in a variance-based sensitivity analysis for proton therapy

Phys Imaging Radiat Oncol. 2021 Dec 2:20:117-120. doi: 10.1016/j.phro.2021.11.005. eCollection 2021 Oct.

Authors

Affiliations

¹ Department of Radiation Oncology, University Hospital, LMU Munich, Munich, Germany.
² Department of Medical Physics, Faculty of Physics, LMU Munich, Munich, Germany.
³ German Cancer Consortium (DKTK), Munich, Germany.
⁴ Department of Radiation Oncology and CyberKnife Center, Faculty of Medicine, University Hospital Cologne, Cologne, Germany.

Abstract

Margin concepts in proton therapy aim to ensure full dose coverage of the clinical target volume (CTV) in presence of setup and range uncertainty. Due to inter-observer variability (IOV), the CTV itself is uncertain. We present a framework to evaluate the combined impact of IOV, setup and range uncertainty in a variance-based sensitivity analysis (SA). For ten patients with skull base meningioma, the mean calculation time to perform the SA including 1.6 × 10⁴ dose recalculations was 59 min. For two patients in this dataset, IOV had a relevant impact on the estimated CTV D_95% uncertainty.

Keywords: Inter-observer variability; Proton therapy; Range uncertainty; Sensitivity analysis; Setup uncertainty.