ESTRO 2025 - Abstract Book

S2964

Physics - Image acquisition and processing

ESTRO 2025

Conclusion: Our findings are consistent with previous phantom and case studies, demonstrating that applying the i4D protocol mitigates interpolation artifacts. Further, i4DCTs exhibit fewer double structure artifacts compared to c4DCT. Exploring the anticipated correlation between artifact frequency and local control, after further data have been collected, will be addressed in future work.

Keywords: 4DCT, image artifacts, local control

References: [1] Sentker et al., 4D CT image artifacts affect local control in SBRT of lung and liver metastases, 2020, Radiotherapy and Oncology. [2] Madesta et al., Deep learning-based conditional inpainting for restoration of artifact-affected 4D CT images, 2024, Medical Physics

1139

Poster Discussion Contour-informed inter-patient deformable registration for more reliable voxel-based analysis of Head-and Neck patients Xingyue Ruan 1,2 , Xia Li 1,3 , Muheng Li 1,4 , Barbara Bachtiary 1 , Zhiling Chen 5,2 , Ye Zhang 1 1 Center for Proton Therapy, Paul Scherrer Institute, Villigen-PSI, Switzerland. 2 Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai, China. 3 Department of Computer Science, ETH Zurich, Zurich, Switzerland. 4 Department of Physics, ETH Zurich, Zurich, Switzerland. 5 Shanghai Advanced Research Institute, Chinese Academy of Sciences, Shanghai, China Purpose/Objective: Voxel-Based Analysis (VBA) challenges the assumption of uniform organ sensitivity by mapping individual dose distributions to a common coordinate system, enabling precise identification of dose-sensitive regions beyond traditional dose-volume histograms. [1] Accurate deformable image registration (DIR) is crucial yet challenging for high-quality VBA, especially with large anatomical variations among patients, as it ensures the proper spatial alignment of dose distributions across individuals. [2] To address this challenge, we equipped CPT-DIR [3] with contour informed regularizations, which improves both global and region-specific registration accuracy, providing the precise anatomic correspondence necessary for inter-patient dose warping.