Related Experiment Video
Updated: Oct 7, 2026
Multianimal Magnetic Resonance Imaging for Tumor Measurements in Pancreatic Cancer Mouse Models
Published on: February 3, 2026
Introduce4πdynamic spot-scanning proton arc therapy (SPArc-4π) for pancreatic cancer: a comparative planning study
Peng Chen1, Peilin Liu2, Xiaoda Cong2
1Department of Radiation Oncology, Taussig Cancer Center, Cleveland Clinic, Cleveland, OH, United States of America.
Abstract:
Objective.Stereotactic body radiotherapy with a simultaneous integrated boost (SBRT-SIB) for locally advanced pancreatic cancer (LAPC) is constrained by the proximity of serial gastrointestinal organs at risk (OARs). Conventional intensity-modulated proton therapy (IMPT) relies on a limited number of fixed beam angles, which may restrict dose shaping around these critical structures. This study evaluated whether non-coplanar spot-scanning proton arc therapy (SPArc-4) could improve OAR sparing while preserving robust target coverage.Approach.10 patients with LAPC were retrospectively selected in this study. For each patient, SBRT-SIB plans were generated using conventional IMPT and SPArc-4. Plan robustness was assessed across 21 uncertainty scenarios. Target coverage, conformity, OAR doses, estimated delivery time, and Lyman-Kutcher-Burman normal tissue complication probability for four gastrointestinal endpoints were compared using the Wilcoxon signed-rank test.Main results.SPArc-4maintained target coverage comparable to IMPT, with similar clinical target volume (CTV) and boost-volume coverage, while CTV conformity improved with SPArc-4(conformity index: 0.50 vs. 0.56;p= 0.02). SPArc-4significantly reduced maximum dose (Gy(RBE)) to the stomach (30.01-24.53), duodenum (35.14-33.14), bowel (32.60-28.91), and spinal cord (15.38 to 5.58; allp0.01). Predicted toxicity decreased across all four gastrointestinal endpoints: gastric bleed risk decreased from 8.19% to 6.15%, grade3 gastrointestinal toxicity from 3.91% to 3.81%, ulceration/perforation from 0.03% to 0.01%, and diarrhea from 24.14% to 22.34% (all). All plans met robustness criteria. The main trade-off was delivery efficiency, with SPArc-4requiring approximately 2-3 min longer delivery time than IMPT.Significance.SPArc-4provides a promising proton planning strategy for pancreatic SBRT-SIB by preserving robust target coverage while improving gastrointestinal organ sparing and reducing predicted toxicity. These findings support further investigation of SPArc-4for safer dose escalation in LAPC.
