3D image reconstruction for symmetric-geometry CT with linearly distributed source and detector in a stationary configuration

In conventional computed tomography (CT) system, generally, the X-ray source moves along a circular or spiral trajectory to achieve volume coverage. However, the gantry rotation increases the manufacturing complexity and dominantly limits the temporal resolution. Recently, a new concept of symmetric-geometry computed tomography (SGCT) was explored, where the sources and detectors are linearly distributed in a stationary configuration. The movements of source and detector are no longer needed in the data acquisition of SGCT, which has the advantage of increasing the scanning speed and simplifying the system construction. In this work, we investigate the there-dimensional (3D) image reconstruction of SGCT, in which the special scanning trajectory is of interest (i.e., tilting straight-line scan). Based on the analysis of imaging geometry and projection data representation, a tilting straight-line analytic reconstruction (TSLA) method is proposed for 3D tomography. The preliminary results of 3D simulated phantoms show that TSLA algorithm for SGCT can reach a reconstruction accuracy which is comparable to that of the helical multidetector CT using PI-original method. On the other hand, with no rotation involved, SGCT can offer fast CT scan and it has the potential in many 3D tomography applications where scanning speed is critical.