Suppression of Streaking Artifacts in Weighted Derivative Backprojection Filtration Reconstruction

摘要

Weighting methods have been widely used and achieved great success in filtered-backprojection (FBP) based CT reconstruction. However, the same weighting methods cooperated with derivative backprojection filtration (DBF) reconstruction usually produce unexpected streaking artifacts, leading in severe unevenness of images. This paper aims to suppress the streaking artifacts in weighted DBF reconstructions. From the analysis on the decomposition of the general form of weighted DBF reconstruction formula, we consider the streaking artifacts as an effect of the combination of the signum function and the derivative of weightings, based on which we extract the streaking artifacts from the raw images in three specific scan modes, i.e., half fan scan, short scan and multi-source scan. Mode-specific correction methods are then proposed to suppress streaking artifacts according to the different characteristics of each scan mode. Evaluation via simulation and phantom studies demonstrates that proposed methods effectively suppress streaking artifacts and smooth the unevenness of images without reducing the spatial resolution.