Progress on Analytical CT Reconstruction Methods:From Circular Trajectory Scanning to Multi-source Linear Trajectory Scanning Imaging

Since the first X-ray computed tomography(CT) scanning was performed by Hounsfield in 1971,CT has mainly walked through five generations and deeply influenced us in many fields,such as medical applications and security inspections.With the development in CT scanning configurations,their reconstruction theories have been growing rapidly.Compared with iterative methods,analytical algorithms can achieve faster reconstruction with simpler error analysis and fewer computing resources,which makes them rather popular in CT products.This review strives to illustrate analytical CT reconstruction methods following the development of scanning modes,from circular and helical trajectories to nonstandard trajectories.As a special case of nonstandard trajectories,recent progress on multi-source linear CT is also highlighted.Finally,we discuss some opportunities and challenges of CT scanning configurations in the future.