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Background Purpose Methods Results Conclusions Phase‐contrast computed tomography (CT) using high‐brilliance, synchrotron‐generated x‐rays enable three‐dimensional (3D) visualization of microanatomical structures within biological specimens, offering exceptionally high‐contrast images of soft tissues. Traditional methods for phase‐contrast CT; however, necessitate a gap between the subject and the x‐ray camera, compromising spatial resolution due to penumbral blurring. Our newly developed technique, Superimposed Wavefront Imaging of Diffraction‐enhanced x‐rays (SWIDeX), leverages a Laue‐case Si angle analyzer affixed to a scintillator to convert x‐rays to visible light, capturing second‐order differential phase contrast images and effectively eliminating the distance to the x‐ray camera. This innovation achieves superior spatial resolution over conventional methods.In this paper, the imaging principle and CT reconstruction algorithm based on SWIDeX are presented in detail and compared with conventional analyzer‐based imaging (ABI). It also shows the physical setup of SWIDeX that provides the resolution preserving second‐order differential images for reconstruction. We compare the spatial resolution and the sensitivity of SWIDeX to conventional ABI.To demonstrate high‐spatial resolution achievable by SWIDeX, the internal structures of four human tissues—ductal carcinoma in situ, normal stomach, normal pancreas, and intraductal papillary mucinous neoplasm of the pancreas—were visualized using an imaging system configured at the Photon Factory's BL14B beamline under the High Energy Accelerator Research Organization (KEK). Each tissue was thinly sliced after imaging, stained with hematoxylin and eosin (H&E) for conventional microscope‐based pathology.A comparison of SWIDeX‐CT and pathological images visually demonstrates the effectiveness of SWIDeX‐CT for biological tissue imaging. SWIDeX could generate clearer 3D images than existing analyzer‐based phase‐contrast methods and accurately delineate tissue structures, as validated against histopathological images.SWIDeX can visualize important 3D structures in biological soft tissue with high spatial resolution and can be an important tool for providing information between the disparate scales of clinical and pathological imaging. [ABSTRACT FROM AUTHOR]

It is crucial to overcome the skull-based contrast loss of cerebral structures in the development of high-resolution X-ray phase-contrast transcranial brain imaging. The present study aimed to determine the consequence of microporous skull-based scattering and its correlation with the contrast loss in a dark-field imaging-computed tomography transcranial brain imaging setup and to suggest methods for visualizing interior structures in analyzer-based X-ray transcranial brain CT imaging. Virtual-skull brain phantoms that mimic the microporous structure of the skull and internal structures including gray/white matter, glioma edema, and the central necrosis of glioma were prepared for wave-propagation simulation of dark-field computed tomography imaging. Reconstruction of refraction angle images and sinogram analysis of angle deviation showed microporous skull-mediated increases in the right-left angle mismatch and out-of-range values in curve fitting with a rocking curve, which was correlated with the contrast loss for internal structures. Correcting the angle mismatch and artificially widening the rocking curve both restored contrast to the internal structures in the reconstructed images. In conclusion, the contrast loss in analyzer-based X-ray diffraction for transcranial brain imaging was related to increases in microporous skull-mediated angle mismatches and out-of-range values when calculating refraction angles using the analyzer rocking curve. This contrast loss may be resolved by using refraction angle measurements from an analyzer crystal with a wider rocking curve or by using an algorithm such as a neural network that can distinguish the left/right refraction angle for a given intensity in a rocking curve. [ABSTRACT FROM AUTHOR]

We demonstrate, what is to the best of our knowledge, a novel optical tomographic method for the visualization of the inner structure of scattering media such as biological tissue in the near-infrared region. We constructed a scanning confocal imaging system with a cross-axes arrangement using optical fibers. This system is based on the optical heterodyne technique and enables the detection of very weak coherence photons that are generated in the spatially restricted confocal region and scattered laterally (90[degrees]) against an incident beam. To evaluate the fundamental imaging capabilities of the system, we assessed measurements from scattering phantoms composed of an Intralipid suspension with varying volume concentrations. The results of this study demonstrate that the right-angled scattered light adheres to the Lambert-Beer law and that the present system can detect light propagating through a distance of ~31[iota] of the mean free path. An inclusion as small as 100 [micro]m can be discriminated in a scattering media with an optical thickness of 4. We investigated the potential of the proposed system for imaging biological tissues in preliminary experiments using samples of chicken breast tissue. OCIS codes: 110.1650, 110.6960, 170.0110, 170.3880, 170.6960.