Limited-Angle Computer Tomography with Truncated Projection Artifacts Removal

Breast cancer is the most common cancer in women and the second most common cancer in the world. Digital breast tomosynthesis (DBT) is an effective medical imaging method. It can reduce the overlap of breast tissue in reconstructed images, which is beneficial to the early detection of breast cancer. DBT uses projection data from a limited range of angles and the simultaneous algebraic reconstruction technique (SART) based reconstruction method. Since the detector’s field of view (FOV) is limited, the updates of the large projection angles in SART cannot include all the voxels of the imaging target, which causes truncated projection artifacts (TPA) at the edges of the image. In this work, we use the images reconstructed by SART to perform re-projection on the virtually expanded detector panel and use a gradient calculation method to compensate for missing projection data to ensure that each update can include all the voxels. Experiments on simulation and human breast demonstrated that TPA can be effectively reduced while retaining the detailed tissue structure, thus improving the image quality at the border and recovering the obscured structural information. It might provide a better imaging result for the consequential clinical diagnosis.