Depth-Layer-Based Patient Motion Compensation for the Overlay of 3D Volumes onto X-Ray Sequences

A novel depth-layer based patient motion compensation approach for 2D/3D overlay applications is introduced. Depth-aware tracking enables automatic detection and correction of patient motion without the iterative computation of digitally reconstructed radiographs (DRR) frame by frame. Depth layer images are computed to match and reconstruct 2D features into 2D+ space. Using standard 2D tracking and the additional depth information, we directly estimate the 3D rigid motion. The experimental results show that with about 30 depth layers a 3D motion can be recovered with a projection error below 2mm.