Trajectory Generation for ROI Expansion in dental CBCT imaging: An Out-of-FOV ROI Annotation Guided Arc Scan-Based Approach

This study introduces a novel optimization approach for source-detector trajectories, designed to simultaneously extend the small dental CBCT field of view (FOV) at specific regions of interest (ROIs) while reducing radiation dose. The proposed algorithm automatically customizes and produces a mechanically feasible arc-based scan trajectory to target predefined ROIs, expanding the FOV beyond the standard range while utilizing only the necessary projections to reconstruct the region of interest, rather than those required for reconstruction of the entire volume. This approach enables a significant reduction in the number of projections. Both qualitative and quantitative analyses, including peak signal-to-noise ratio (PSNR) values greater than 30 dB and structural similarity index measure (SSIM) scores above 0.9, demonstrate that the method successfully enhances the FOV while maintaining high image quality. Notably, the approach achieves a significant reduction in the number of projections up to 47% compared to the conventional limited-angle circular trajectory. This is the first study to explore the simultaneous extension of the FOV and radiation dose reduction in dental CBCT imaging, providing a promising solution for improving clinical outcomes and treatment planning in next-generation CBCT systems.