S1737
Physics - Dose prediction/calculation, optimisation and applications for particle therapy planning
ESTRO 2026
but its robustness under cardiopulmonary motion remains uncertain[2]. This study aimed to evaluate the impact of respiratory and cardiac motion on proton dose delivery and to determine optimal beam configurations for VT treatment planning. Material/Methods: Respiratory 4DCT (r4DCT) data from 12 patients and cardiac 4DCT (c4DCT) data from 6 patients were retrospectively analyzed. The left ventricle was divided into four regions (anterior, inferior, lateral, septal) [3]to simulate different target locations. Single-field plans with multiple beam angles and three-field plans were generated using robust optimization (±3.5% range and 5 mm setup uncertainty) and evaluated via 4D dynamic dose(4DDD) accumulation. Dose-volume metrics (V25, D95%, HI, CI) were compared to quantify motion effects and plan robustness[2, 4].
Conclusion: High-speed proton therapy within a short breath-hold is feasible on existing clinical systems, providing motion-robust, precise, and cost-effective treatment. This framework enables practical sub-10-second field delivery for large lung tumors, improving patient comfort, throughput, and access to proton therapy. References: Maradia, V., Yue, N., Molzahn, A., Wang, J., Pankuch, M., Charyyev, S., & Loo, B. W. Jr. (2025).High-speed proton therapy within a short breath-hold. arXiv preprint arXiv:2510.06766. https://arxiv.org/abs/2510.06766 Keywords: proton therapy, lung cancer Digital Poster 2578 4D robust evaluation of intensity-modulated proton therapy for ventricular tachycardia: impact of cardiopulmonary motion Shuting Wang 1,2 , Xiaoying Fan 1,2 , Yong Yin 2 , Tianyuan Dai 2 1 Department of Graduate, Shandong First Medical University, Shandong Academy of Medical Sciences, Jinan, China. 2 Department of Radiation Oncology Physics and Technology, Shandong Cancer Hospital and Institute, Shandong First Medical University and Shandong Academy of Medical Sciences, Jinan, China Purpose/Objective: Radiotherapy has emerged as an effective noninvasive treatment for refractory ventricular tachycardia (VT)[1]. Given the high sensitivity of cardiac structures, proton therapy offers potential dosimetric advantages,
Figure 1 Relative position of each target and equally spaced field angle settings. (a) Beam arrangement for ICTV-A. (b) Beam arrangement for ICTV-I. (c) Beam arrangement for ICTV-L. (d) Beam arrangement for ICTV-S. The contour is CTV. Results: Beam angle strongly influenced target coverage and organ sparing. Respiratory motion induced larger dose variations than cardiac motion. Optimal beam angles were 60° for anterior/inferior, 90° for lateral, and 30° for septal targets. Multi-field plans improved heart and lung protection but exhibited slightly reduced target robustness, particularly for inferior and lateral walls. Inter-fractional analysis confirmed greater reproducibility for anterior and septal targets. The 4DDD results demonstrated that respiratory-induced dose distortion exceeded cardiac motion effects across all configurations.
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