An efficient cone beam filtered back-projection (CB-FBP) reconstruction algorithm for a circle-plus-two-arc orbit

The circle-plus-are orbit surpasses other 'circle-plus' orbits for the application of X-ray cone beam (CB) volume CT in image-guided interventional procedures requiring intraoperative imaging, in which movement of a patient table is to be avoided. A CB circle-plus-two-arc orbit satisfying the data sufficiency condition (DSC) and a filtered back projection (FBP) algorithm to reconstruct longitudinally unbounded objects is presented here. In the circle sub-orbit, the algorithm employs Feldkamp's formula and another FBP implementation. In the arc sub-orbits, an FBP solution is obtained originating from Grangeat's formula, and the reconstruction computation cost is significantly reduced using a window function to exclude the redundancy in the Radon domain. The performance of the algorithm has been evaluated through computer simulation using the Disc and Shepp phantoms, showing that the algorithm can regionally reconstruct longitudinally unbounded objects efficiently, and is stable with X-ray quantum noise.