Accurate Image Reconstruction of a Small ROI using Fully Truncated Data in Differential Phase Contrast Computed Tomography

Differential phase contrast computed tomography (DPC-CT) is a novel X-ray imaging method that uses the wave properties of imaging photons as the contrast mechanism. It has been demonstrated that differential phase contrast images can be obtained using either synchrotron radiation or a conventional X-ray tube and a Talbot-Lau-type interferometer. These data acquisition systems offer only a limited field of view and thus, are prone to data truncation. In this work, we demonstrated that a small region of interest (ROI) of a large object can be accurately and stably reconstructed using fully truncated projection datasets provided that a priori information on electron density is known inside the ROI. The method reconstructs an image iteratively to satisfy a group of physical conditions using a projection onto convex set (POCS) algorithm. This POCS algorithm is validated using numerical simulations.