Computed tomography (CT) has been used worldwide for decades as one of the
most important non-invasive tests in assisting diagnosis. However, the ionizing
nature of X-ray exposure raises concerns about potential health risks such as
cancer. The desire for lower radiation dose has driven researchers to improve
the reconstruction quality, especially by removing noise and artifacts.
Although previous studies on low-dose computed tomography (LDCT) denoising have
demonstrated the effectiveness of learning-based methods, most of them were
developed on the simulated data collected using Radon transform. However, the
real-world scenario significantly differs from the simulation domain, and the
joint optimization of denoising with modern CT image reconstruction pipeline is
still missing. In this paper, for the commercially available third-generation
multi-slice spiral CT scanners, we propose a two-stage method that better
exploits the complete reconstruction pipeline for LDCT denoising across
different domains. Our method makes good use of the high redundancy of both the
multi-slice projections and the volumetric reconstructions while avoiding the
collapse of information in conventional cascaded frameworks. The dedicated
design also provides a clearer interpretation of the workflow. Through
extensive evaluations, we demonstrate its superior performance against
state-of-the-art methods