Feasibility Study of a Cold-Cathode Flat-Panel X-Ray Source With Microarray Anode Target for Grating Interferometer Computed Tomography

摘要

Talbot-Lau grating interferometer (GI) can provide valuable tricontrast [absorption, differential phase contrast (DPC), and dark field (DF)] information about the samples to be imaged. However, the source grating G0 presents severe challenges associated with fabrication and limited efficiency. In this study, a novel cold-cathode flat-panel X-ray source with microarray anode target was proposed for GI computed tomography, which can eliminate the use of G0. Its cathode is characterized as densely arranged ZnO nanowires (NWs) to provide large amounts of electrons, whereas the micro periodic distributed Al-Mo-Al strips were used as the anode target to generate the structured X-ray illumination required for Talbot-Lau GI. The performance of the source was fully studied by accurately modeling its geometry via EGSnrc. The flat-panel X-ray source GI computed tomography was then simulated by using the Fresnel-Kirchhoff diffraction theory. Furthermore, a polymethyl methacrylate (PMMA) cylinder and a Shepp-Logan phantom were used to evaluate the imaging performance of the system. Due to the elimination of G0, our proposed flat-panel source GI has 153.05% higher X-ray photons utilization efficiency than the conventional Talbot-Lau GI, which results in tricontrast images with less noise. The proposed X-ray source can replace the laboratory source and grating G0 and may provide new possibilities for Talbot-Lau GI.

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