Abstract: Low-dose computed tomography (CT) reconstruction has become the focus of X-ray CT imaging study. In this
paper, we propose an improved prior image constrained compressed sensing (PICCS) reconstruction approach. A penalized
weighted least-squares approach was adopted to realize the line integral projection (sinogram) data restoration, followed by
filtered back-projection (FBP) of the restored sinogram data for image reconstruction. Finally, the FBP image as the prior
image was used for PICCS approach for dose reduction. Qualitative and quantitative evaluations were carried out with
computer simulation. The results showed that the present approach yielded noticeable gains over the original PICCS
approach for dose reduction in terms of noise-induced artifacts suppression and edge detail preservation.