Development of Superimposed Wavefront Imaging of Diffraction-Enhanced X-Rays (SWIDeX) for High-Spatial-Resolution Refraction-Contrast CT

Abstract

Superimposed Wavefront Imaging of Diffraction-enhanced X-rays (SWIDeX) is a novel refraction-contrast X-ray CT imaging technique in which a thin Si single-crystal analyzer plate is placed in direct contact with the X-ray camera to acquire projections corresponding to the second derivative of the refractive index distribution 𝛿. This configuration enables close proximity between the specimen and the detector, which has been difficult to achieve in conventional phase-contrast imaging, thereby significantly reducing image blurring caused by the finite X-ray focal spot size. In this study, we present the imaging principle and reconstruction theory of SWIDeX, compare its image quality with that of XDFI using human biological tissue specimens, and demonstrate that the algebraic reconstruction method incorporating Total Variation regularization effectively reduces the required number of CT projections by exploiting the sparsity of SWIDeX-CT.