Integrating Spot-Scanning Proton Arc Therapy with Functional Avoidance Strategies to Reduce Pulmonary Toxicity

Authors

Yingxuan Chen, Thomas Jefferson UniversityFollow
Peilin Liu
Xiaoda Cong
Edward Castillo
Richard Castillo
Inga Grills
Craig Stevens
Xiangkun Xu
Xiaoqiang Li
Yevgeniy Vinogradskiy, Thomas Jefferson UniversityFollow
Xuanfeng Ding

Document Type

Article

Publication Date

12-1-2025

Comments

This article is the author's final published version in Physics and Imaging in Radiation Oncology, Volume 36, October 2025, Article number100876.

The published version is available at https://doi.org/10.1016/j.phro.2025.100876. Copyright © 2025 The Author(s).

Abstract

Background and purpose: Functional avoidance radiotherapy has emerged as a promising technique using functional imaging to minimize pulmonary toxicity by reducing doses to functional lung. This study aims to investigate the potential dose-volume advantages of a novel spot-scanning proton arc (SPArc) therapy for functional avoidance radiotherapy with four-dimensional computed tomography (4DCT)-based ventilation imaging.

Material and methods: Twenty-five patients from a prospective functional avoidance clinical trial treated with intensity-modulated photon radiotherapy were included. Robustly optimized intensity modulated proton therapy (IMPT) and SPArc plans were generated in RayStation. Functional lung contour was derived from the 4DCT-based ventilation imaging and utilized as an optimization structure in photon as well as IMPT and SPArc functional planning. The dose distributions were compared, and normal tissue complication probability (NTCP) models were applied to estimate the probability of pulmonary toxicity.

Results: Using clinical photon plans as the baseline for comparison, both proton plans achieved equivalent target coverage and reduced dose to organs at risk. Compared with photon plans, the median absolute reduction of fV_20Gy (the volume of functional lung receiving ≥ 20 Gy) was 3.7 percentage points (pp) with IMPT and 13.0 pp with SPArc. Using fV_20Gy for NTCP estimation, the median reduction of probability of grade ≥ 2 pneumonitis was 5.0 pp with IMPT and was 14.9 pp with SPArc.

Conclusions: Our study highlighted the potential of SPArc to spare dose to functional lung. NTCP results further indicated that the risk of pulmonary complications can be reduced with SPArc compared to photon or IMPT for functional avoidance radiotherapy.

Recommended Citation

Chen, Yingxuan; Liu, Peilin; Cong, Xiaoda; Castillo, Edward; Castillo, Richard; Grills, Inga; Stevens, Craig; Xu, Xiangkun; Li, Xiaoqiang; Vinogradskiy, Yevgeniy; and Ding, Xuanfeng, "Integrating Spot-Scanning Proton Arc Therapy with Functional Avoidance Strategies to Reduce Pulmonary Toxicity" (2025). Department of Radiation Oncology Faculty Papers. Paper 221.
https://jdc.jefferson.edu/radoncfp/221

Creative Commons License

This work is licensed under a Creative Commons Attribution 4.0 License.

Language

English