S2074
Physics - Image acquisition and processing
ESTRO 2026
Conclusion: The HyperSight CBCT demonstrated improved image quality compared with conventional CBCT. It showed slightly superior performance across image quality assessments, improved clinical CBCT scan quality, and significantly reduction in metal artifacts. These characteristics allow clinical integration for adaptive radiotherapy and applications in dose calculation.
Continued optimization and calibration are recommended to exploit its capabilities. Keywords: CBCT, Image quality, HyperSight
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Reduction of radiation target volume definition for glioma patients by integrating biopsy sampling for radiographically occult disease Gregory Buti, Helen A Shih, Thomas R Bortfeld, Ali Ajdari Radiation Oncology, Mass General Brigham, Boston, USA Purpose/Objective: Reducing the high-dose radiation volume is desirable for brain tumor patients to avoid long term neuro- cognitive deficits, as long as tumor control remains uncompromised. We designed a computational methodology to gain maximum information on the tumor volume of glioma prior to radiotherapy planning through MRI-informed biopsy sampling with the goal of redistributing the clinical target volume (CTV) from biopsy-negative towards biopsy-positive areas. Material/Methods: Pre-operative T1-contrast MRI and T2-FLAIR images of three glioblastoma patients were used to determine the radiation targets: macroscopic (T1-hyperintensity) tumor volume (GTV) and high-risk (T2-FLAIR hyperintensity) and low-risk CTV by a neuro-radiation oncologist. Tumor probability maps were estimated based on (a) distance away from the macroscopic tumor volume and (b) additional information of diffusion tensor imaging (DTI)-based preferred tumor invasion along white matter tracts. An Optimal Budget Allocation (OBA) methodology was formulated and solved to find the optimal biopsy locations under limited sampling “budget”, balancing expected information gain against location-dependent cost of biopsy sampling. A simulation study was performed to analyze the rate at which low-risk CTV is rejected, depending on the number of negative biopsy samples required for rejection. Results: Using a biopsy sampling budget equal to five, the OBA method successfully returned optimal biopsy locations across all 6 experiments (3 patients x 2 probability
The surveys rated the image quality of the HyperSight CBCT as superior (15%) to conventional CBCT with more accurate automatic contours by the automated segmentation software. The comparison of patient with metal prothesis scans showed significantly improved image quality and metal artifact reduction of HyperSight CBCT (Figure2).
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