New super-short-scan algorithms for fan-beam and cone-beam reconstruction

This paper deals with image reconstruction from fan-beam and cone-beam projections when only a region of interest (ROI) is to be reconstructed. We propose a new fan-beam FBP algorithm which can achieve exact ROI reconstruction if and only if all lines passing through the ROI intersect the source trajectory. This requirement on the scanning range is significantly weaker compared to that required by the conventional fan-beam FBP algorithm. Furthermore, this algorithm is extended to cone-beam tomography when the source trajectory is a short-arc on the single circle.