Image Reconstruction for In-Line Phase Contrast CT by Offsetting X-Ray Source Twice

X-ray in-line phase contrast computed tomography (PC-CT) can provide imaging contrast that is orders of magnitude better than conventional absorption-based CT and has attracted some interest in many fields such as life science, medicine and biomedical engineering. In conventional methods, PC-CT needs two rotation scans to retrieve the phase line integral projection from the recorded original data. It is usually implemented by shifting detector or object twice. However, it is sometimes impossible due to the experimental constraints. In this paper, an image reconstruction algorithm is proposed which permits that two rotation scans are completed by offsetting the X-ray source twice. This work comprises a simulation study of the proposed method and its experimental verification using a biomedical material sample dataset measured at an in-line PC-CT system. It simplifies the imaging conditions and will push the engineering applications of in-line PC-CT.