ESTRO 2025 - Abstract Book

S3191

Physics - Inter-fraction motion management and offline adaptive radiotherapy

ESTRO 2025

Results: Significant enhancement in CBCT image quality was observed improving auto-segmentation performance (Figure 1). Figure 2 shows the mean and standard deviation of the DSC and MDA compared to the ground truth; for CBCT Iris and sCT. A DSC of 0.7 or higher is considered good overlap 3 , which was observed for most contours. For the colon, a 0.68 DSC is reasonable; where 0.5-0.7 is considered good overlap for complex anatomy based on published data 4 . The MDA for most of the contours were less than 3mm. The mean HU difference for the various tissue types were within ESTRO guideline tolerances for which a dose difference would not exceed 1%. The mean gamma analysis for the dose calculated was 99.6% for 3%/3mm and 98.6% for 2%/2mm exceeding the passing threshold. These results are comparable to the sCT generated with the previously evaluated model.