FBP initialization for transition artifacts reduction in statistical X-ray CT reconstruction

When statistical reconstruction (SR) algorithms are applied to X-ray CT data, the resulting images may contain some disturbing streak artifacts emerging from high-contrast structures. Extremely high number of iterations needed to remove such disturbances may seriously slow down the reconstruction process. In this paper we demonstrate (using the Ordered Subsets Convex algorithm) that these artifacts can be adequately suppressed if statistical reconstruction is initialized with images generated by means of analytical algorithms like Filtered Back Projection (FBP). This allows the reconstruction time to be shortened by even as much as one order of magnitude. Although the initialization of the statistical algorithm with FBP image introduces some additional noise into the first iteration of OSC reconstruction, the resolution-noise trade-off and the contrast-to-noise ratio of final images are not markedly compromised.