A half-scan error reduction based algorithm for cone-beam CT

The most popular Feldkamp algorithm for cone-beam image reconstruction assumes a scanning circle, and performs well only with a small cone angle. In this report, we propose a Feldkamp-type algorithm to increase the cone angle by several folds at a radiation dose comparable to that required by the classic Feldkamp algorithm. In our scheme, two half-scans of different radii are used. Then, approximate reconstructions from two half-scans are combined to produce a superior image volume by utilizing a relationship between the half-scan reconstruction error and the scanning locus radius. The merit of this half-scan error reduction based (HERB) algorithm is demonstrated in numerical simulation with the 3D Shepp-Logan phantom.