A Novel Stationary CT Scheme Based on High-Density X-Ray Sources Device

Abstract

With the introduction of cold electron sources such as nanotubes, X-ray sources became small in size so that many sources are installed in array to form stationary CT, which brings benefits of simplicity in mechanism and fast response. However, the nanotube-based X-ray source is still singly packaged and hence density of X-ray sources is limited, which introduces severe sparse-view artifacts and could not be used in practice. With the invention of X-ray sources device based on ZnO nanowires as cold electron emitters, a large amount of X-ray sources is first integrated in a flat panel device. In this study, we design a stationary CT architecture using high-density sources devices, called HD-SCT, and develop corresponding reconstruction algorithm. Specifically, several flat panel detectors and X-ray sources devices are spliced together to form a source-detector plate. Multiple source-detector plates are organized as a polygon that encloses object to complete CT scanning. In HD-SCT, X-ray sources are close to object which can significantly decrease CT device volume. The X-ray beam emitted by each source just cover part of object and the spot sources alternately light to completely scan object. Simultaneously, we propose a reconstruction method for the specific configuration which adopts an iterative algorithm to resolve the reconstruction based on alterative part projections, as well as a novel correction process of projection completion for the shadowed area of placing X-ray source devices. To validate the design of the proposed HD-SCT, we execute a series of simulation experiments, which show that the proposed HD-SCT and corresponding reconstruction method effectively remove the artifacts caused by the embed X-ray source device. The results also disclose that with the increase of density of X-ray sources, the resolution of reconstruction has been dramatically improved, which demonstrates the practical value of introducing high-density X-ray sources device into stationary CT design.

Keywords

• Stationary CT scheme
• high-density X-ray sources devices
• source-detector plate
• iterative reconstruction