A semi-stationary CT system

With distributed sources along a helix trajectory, the helical interlaced source detector array (HISDA) requires no rotation while scanning, thus improving temporal resolution and ensuring mechanical stability. However, in this system, gaps exist in the detector array where sources are placed, resulting in the non-measurement of projection data in gaps. To solve this problem, we propose the semi-stationary CT, which can move the table or gantry based on the HISDA CT. This additional movement can reshape the effective helix trajectory, reducing the required detector area, so that the gaps are out of this area. We discuss the minimum moving velocity to meet the theoretical data sufficiency condition. Furthermore, the velocity condition is also investigated to apply the exact reconstruction algorithm. Simulation studies verified that the proposed scanning method can solve the data absence problem and improve the imaging quality. This semi-stationary CT can be designed with less cost and scattering in comparison with the stationary HISDA CT.