ESTRO 2025 - Abstract Book

S3060

Physics - Image acquisition and processing

ESTRO 2025

Results: Use of HS CBCT led to improved confidence in image matching by RTTs for lung (mean 4.0 [95% CI 3.7 – 4.3]) and liver (mean 4.5 [95% CI 4.3-4.7]) when compared to TB CBCT (Figure 1). HS CBCT for breast cases had a 10 times lower mAs than TB CBCT (29 mAs vs 270 mAs) but still resulted in equivalency of matching confidence (mean 3.4 [95% CI 3.0-3.7]). HS CBCT led to inferior contouring confidence when compared to FBCT (Figure 2). Mean contouring confidence decreased for all structures from 4.6 to 3.5 (p <0.001) for esophagus, 4.6 to 3.8 (p <0.001) for adjacent bowel, 4.6 to 3.3 (p<0.001) for heart, and 4.7 to 3.6 (p<0.001) for breast target structures.