ESTRO 2025 - Abstract Book

S3010

Physics - Image acquisition and processing

ESTRO 2025

superior-inferior (SI) directions. Participant rotational deviation was 0.56/0.69° in the coronal plane and 0.56/1.13° in the sagittal plane. Clinical supine inter-fraction shifts had mean absolute deviation of 2.3mm LR, 4.5mm AP, 7.8mm SI, 0.12° coronal plane, and 0.46° sagittal plane.

Conclusion: First-in-human upright CBCT images on a C-arm linac allow the visualisation of key structures with adequate geometric accuracy for image guided radiation therapy. Initial observations of upright participant setup stability and reproducibility appear comparable to those in the supine position.

Keywords: Upright Radiation Therapy, CBCT, IGRT

References: 1. Hegarty, S., et al., Please Place Your Seat in the Full Upright Position. Frontiers in Oncology, 2022. doi:10.3389/fonc.2022.821887 2. Rahim, S., et al., Upright Radiation Therapy. Frontiers in Oncology, 2020. doi:10.3389/fonc.2020.00213 3. Volz, L., et al., Opportunities and challenges of upright patient positioning in radiotherapy. Phys Med Biol, 2024. doi:10.1088/1361-6560/ad70ee