FROM A SMALL NUMBER OF PROJECTIONS

In the CT image reconstruction, we investigate the obtainable information content about object to be imaged from its finite number of projections and the structure of reconstruction emr due to the insufficient number of projections. We can explicitly demonstrate that the mechanism which limits the resolution of CT image is angular alising. Based on this investigation, a new CT image reconstruction algorithm is developed, which produces high quality artifactless images even in the case of a small number of projections. The image quality reconstructed by proposed algorithm is superior to that by the conventional filtered backprojection(FBP) algorithm.