Accurate reconstruction algorithm for bilateral differential phase signals

Background The differential phase computed tomography (DP-CT) imaging is a kind of X-ray-phase-based CT methods, which is widely used in various X-ray imaging laboratories. At present, a collection of projections with the horizontal direction (perpendicular to the sample rotation axis) DP information is often acquired in DP-CT. In an ideal experiment, if the background is zero, then we can accurately reconstruct the information of each direction of the sample with horizontal data only. Actually, background information will produce streaking artifacts to affect the resolution in directions other than the horizontal direction. Purpose To mitigate the streaking artifacts in the conventionally reconstructed DP-CT images. Method This study develops a novel analytical DP-CT reconstruction framework by jointly using the bilateral DP information obtained along two perpendicular directions. In addition, a new data acquisition scheme is also proposed to quickly acquire the bilateral DP signal without the need of changing the direction of refraction signal acquisition. Results Experimental results demonstrate that this new algorithm is able to greatly reduce the streaking artifacts on DP-CT images.