A Beam-Specific Optimization Target Volume for Stereotactic Proton Pencil Beam Scanning Therapy for Locally Advanced Pancreatic Cancer
JournalAdvances in Radiation Oncology
MetadataShow full item record
AbstractPurpose: We investigate two margin-based schemes for optimization target volumes (OTV), both isotropic expansion (2 mm) and beam-specific OTV, to account for uncertainties due to the setup errors and range uncertainties in pancreatic stereotactic pencil beam scanning (PBS) proton therapy. Also, as 2-mm being one of the extreme sizes of margin, we also study whether the plan quality of 2-mm uniform expansion could be comparable to other plan schemes. Methods and Materials: We developed 2 schemes for OTV: (1) a uniform expansion of 2 mm (OTV2mm) for setup uncertainty and (2) a water equivalent thickness–based, beam-specific expansion (OTVWET) on beam direction and 2 mm expansion laterally. Six LAPC patients were planned with a prescribed dose of 33 Gy (RBE) in 5 fractions. Robustness optimization (RO) plans on gross tumor volumes, with setup uncertainties of 2 mm and range uncertainties of 3.5%, were implemented as a benchmark. Results: All 3 optimization schemes achieved decent target coverage with no significant difference. The OTV2mm plans show superior organ at risk (OAR) sparing, especially for proximal duodenum. However, OTV2mm plans demonstrate severe susceptibility to range and setup uncertainties with a passing rate of 19% of the plans meeting the goal of 95% volume covered by the prescribed dose. The proposed dose spread function analysis shows no significant difference. Conclusions: The use of OTVWET mimics a union volume for all scenarios in robust optimization but saves optimization time noticeably. The beam-specific margin can be attractive to online adaptive stereotactic body proton therapy owing to the efficiency of the plan optimization.
Rights/Terms© 2021 The Authors.
Keywordstereotactic proton pencil beam scanning therapy
Identifier to cite or link to this itemhttp://hdl.handle.net/10713/16795
- Impact of errors in spot size and spot position in robustly optimized pencil beam scanning proton-based stereotactic body radiation therapy (SBRT) lung plans.
- Authors: Rana S, Rosenfeld AB
- Issue date: 2021 Jul
- Superiority in Robustness of Multifield Optimization Over Single-Field Optimization for Pencil-Beam Proton Therapy for Oropharynx Carcinoma: An Enhanced Robustness Analysis.
- Authors: Stützer K, Lin A, Kirk M, Lin L
- Issue date: 2017 Nov 1
- Evaluation of OAR dose sparing and plan robustness of beam-specific PTV in lung cancer IMRT treatment.
- Authors: Chang Y, Xiao F, Quan H, Yang Z
- Issue date: 2020 Oct 17
- Impact of robust treatment planning on single- and multi-field optimized plans for proton beam therapy of unilateral head and neck target volumes.
- Authors: Cubillos-Mesías M, Baumann M, Troost EGC, Lohaus F, Löck S, Richter C, Stützer K
- Issue date: 2017 Nov 28
- A Probability-Based Investigation on the Setup Robustness of Pencil-beam Proton Radiation Therapy for Skull-Base Meningioma.
- Authors: Zou W, Kurtz G, Nakib M, Burgdorf B, Alp M, Li T, Lustig R, Xiao Y, Dong L, Kassaee A, Alonso-Basanta M
- Issue date: 2021 Winter