Exploiting Symmetry in Fan Beam CT: Overcoming Third Generation Undersampling

Abstract

A new reconstruction algorithm is presented for tomographic reconstruction from fan beam data acquired with a quarter detector shift. This algorithm exploits the reflection property of the divergent beam transform by representing the sample and reflected points as a discrete, multichannel sample set. A doubling of the reconstruction resolution is achieved by increasing the number of source locations without changing the detector sample density. The algorithm can be used to reconstruct images from a third generation CT scanner at the maximum resolution consistent with the frequency characteristics of the detector.