ESTRO 2025 - Abstract Book

S3260

Physics - Intra-fraction motion management and real-time adaptive radiotherapy

ESTRO 2025

2440

Digital Poster Integrating Surface Guidance to Optimize Daily CBCT in Advanced Radiotherapy: A Multi-Site Evidence-Based Study Adhimoolam Saravana Kumar 1 , Leel Malar 1 , Sankar Sekar 1 , Dinesh Babu 1 , Veluthattil Aswin Chandran 2 , N Nithiyaanandan 2 , Thirumala Balaji 3 , Marco Esposito 4 1 Medical Physics, PSG Hospitals, Coimbatore, India. 2 Radiation Oncology, PSG Hospitals, Coimbatore, India. 3 Institute of Oncology, PSG Hospitals, Coimbatore, India. 4 Medical Physics, The Abdus Salam International Centre for Theoretical Physics, Trieste, Italy Purpose/Objective: Surface Guided Radiotherapy (SGRT) is a new technology in Image Guided Radiation Therapy (IGRT) that significantly improves the precision and accuracy of treatment delivery while minimizing the exposure of healthy tissues, particularly the tissues or organs close to the treatment site. In recent days, the three-point method and cone-beam computed tomography (CBCT) were commonly used for daily patient positioning verification before treatment. Currently, SGRT is also introduced, offering the potential to reduce treatment time and imaging dose by decreasing the frequency of CBCT scans. This study aimed to compare the real time positional shifts obtained from the three point method (2D), Image-Guided Radiation Therapy (IGRT) (3D), and SGRT, as well as to develop a clinical workflow for SGRT implementation in advanced radiotherapy based on the data collected at PSG Hospitals Material/Methods: PSG Hospitals has recently become the first hospital in the country to install the Catalyst ⁺ HD SGRT system. A total of 50 patients were retrospectively selected from five different sites, encompassing 950 treatment fractions using 3D conformal radiation therapy and Rapid Arc. A total of 950 kV CBCT images were evaluated for patient setup verification and compared with the real time shifts observed using SGRT. Results: Table 1 presents the analysis of mean positional shifts across 950 treatment fractions, comparing IGRT and SGRT. Figure 1, presents the site-wise comparison of mean shift values between IGRT and SGRT.

Figure 1. Site-Wise Comparison of Mean Shift Values Between IGRT and SGRT