Iterative reconstruction for multi-source inverse geometry CT: a feasibility study

In a 3rd generation CT system, a single source projects the entire field of view (FOV) onto a large detector opposite to the source. In multi-source inverse geometry CT imaging, a multitude of sources sequentially project complementary parts of the FOV on a much smaller detector. These sources may be distributed in both the trans-axial and axial directions and jointly cover the entire FOV. Multi-source CT has several important advantages, including large axial coverage, improved dose-efficiency, and improved spatial resolution. One of the challenges of this concept is to ensure that no artifacts emerge in the reconstructed images where the sampling switches from one source to the next. This work studies iterative reconstruction for multi-source imaging and focuses on the appearance of such artifacts. For that purpose, phantom data are simulated using a realistic multi-source CT geometry, iteratively reconstructed and inspected for artifact content. More realistic experiments using rebinned clinical datasets (emulating a multi-source CT system) have also been performed. The results confirm the feasibility of artifact-free multi-source CT imaging in both full-scan and half-scan situations.