A Cone-Beam Reconstruction Algorithm Based on Nutating Line Filtration for Single Circular Trajectory

Traditionally, projection data are filtered along the horizontal lines on the detector plane for the FDK algorithm. This makes it impossible that the same voxels involved in the filtering at one projection angle are also filtered together at the other projection angles. To keep filtering together as much as possible for the same voxels at different projection angle, a cone-beam algorithm is presented based on the nutating line by modifying a result due to Turbell. Unlike Turbell´s method, the proposed algorithm avoids the process step of rebinning the cone-beam data to 3D parallel-beam data. In addition, to further enlarge reconstruction volume and make the short-scan reconstruction, another FBP term suggested by Zhuang et al. is also modified into the final formula. The performance of the proposed algorithms is compared with other related algorithms through computer simulation using the Shepp-Logan phantom. The experiment results show that the proposed algorithm can substantially compensate for the low density drop inherent to the FDK-type algorithm