Yuan Qing-Xi

Penetrating view of nano-structures in Aleochara verna spermatheca and flagellum by hard X-ray microscopy

A penetrating view of the three-dimensional nanostructure of female spermatheca and male flagellum in the species Aleochara verna is obtained with 100-nm resolution using a hard X-ray microscope, which provides a fast noninvasive imaging technology for insect morphology. Through introducing Zernike phase contrast and heavy metal staining, images taken at 8 keV displayed sufficient contrast for observing nanoscale fine structures, such as the spermatheca cochleate duct and the subapex of the flagellum, which have some implications for the study of the sperm transfer process and genital evolution in insects. This work shows that both the spatial resolution and the contrast characteristic of hard X-ray microscopy are quite promising for insect morphology studies and, particularly, provide an attractive alternative to the destructive techniques used for investigating internal soft tissues.

Reconstructing a complex field from a series of its near-field diffraction patterns

We propose a method for reconstructing a complex field from a series of its near-field diffraction patterns. This method is based on the paraxial Fresnel diffraction equation without making further approximations. Numerical simulations are presented showing that a complex field can even be reconstructed with moderate qualities from its two near-field diffraction patterns and almost exact reconstructions can be obtained when three or more diffraction patterns are used. We also show by numerical simulation that the correct diffraction distances can be recovered in case only coarsely measured values are available. This method may be applied to phase imaging of weak-absorption objects.

Comparative analysis of phase extraction methods based on phase-stepping and shifting curve in grating interferometry

Two phase extraction methods which are based separately on phase-stepping and shifting curve are mainly used in phase-sensitive imaging in gating interferometry to determine the x-ray phase shift induced by an object in the beam. In this paper, the authors perform a full comparative analysis and present the main virtues and limitations of these two methods according to the theoretical analysis of the grating interferometry.

X-ray diffraction enhanced imaging study of intraocular tumors in human beings

Diffraction enhanced imaging (DEI) with edge enhancement is suitable for the observation of weakly absorbing objects. The potential ability of the DEI was explored for displaying the microanatomy and pathology of human eyeball in this work. The images of surgical specimens from malignant intraocular tumor of hospitalized patients were taken using the hard X-rays from the topography station of Beamline 4W1A at Beijing Synchrotron Radiation Facility (BSRF). The obtained radiographic images were analyzed in correlation with those of pathology. The results show that the anatomic and pathologic details of intraocular tumors in human beings can be observed clearly by DEI for the first time, with good visualization of the microscopic details of eyeball ring such as sclera, choroids and other details of intraocular organelles. And the best resolution of DEI images reaches up to the magnitude of several tens of μm. The results suggest that it is capable of exhibiting clearly the details of intraocular tumor using DEI method.

Synchrotron radiation (SR) diffraction enhanced imaging (DEI) of chronic glomerulonephritis (CGN) mode.

OBJECTIVE The aim of this study is to investigate microstructural changes in chronic glomerulonephritis (CGN) rabbit model under diffraction enhanced imaging (DEI) technology of synchrotron radiation (SR). MATERIALS AND METHODS The chronic glomerulonephritis (CGN) models were obtained within two months after 5 New Zealand white rabbits were treated with doxorubicin hydrochloride. Blood exams, urine tests and kidney histological studies were carried out after the 5 rabbits were humanely sacrificed by hyperanesthesia. The kidney tissues were fixed in 4% formalin for one week before DEI experiment, with another 5 normal rabbits used as the control group. The experiment was performed at Beijing Synchrotron Radiation Facility (BSRF) with a 4W1A beam line (beam energy was 14keV). On routine scanning process, the rocking curve was detected, and slope position on the curve was selected to make a 360° spatial CT scan; DEI reconstruction software was used to generate a 3-dimensional image, from which the difference in grey value between the chronic glomerulonephritis (CGN) group and the control group was measured and analyzed using MATLAB and SPSS. RESULT Without radio-contrast, DEI provided clear visibility of the microstructures including artery, vein, straight collecting ducts, papillary tubules, glomeruli in both the chronic glomerulonephritis (CGN) group and the control group, with a spatial resolution as low as 10μm. MATLAB grey value extraction and SPSS analysis showed that cortex of CGN group (91 to 112) lost more gray value compared to the control group (121 to 141), T tests P <  0.05. Equivalant cortical ROI (data points 450×80) quantitative analysis showed that gross grey value of CGN group (ranking from 55 to 160) was smaller than the control group (ranking from 75 to 175). DEI images correlated well with pathologic images. Morphological changes in the microstructure of contstartabstractCGN kidney was revealed, due to the advantage of phase-contrast imaging (PCI) mechanism, and the diagnostic value of CGN by synchrotron radiation (SR) phase-contrast imaging (PCI) technology was evaluated. CONCLUSION Synchrotron radiation (SR) diffraction enhanced imaging (DEI) experiment makes non-contrast CGN diagnosis possible in the rabbit model studied. With improvement of laboratory equipment and image analyzer in clinical practice, diffraction enhanced imaging (DEI) could fundamentally become a new diagnostic method for CGN.

Medical application of diffraction enhanced imaging in mouse liver blood vessels

Neovascularization is correlative with many processes of diseases, especially for tumor growth, invasion, and metastasis. What is more, these tumor microvessels are totally different from normal vessels in morphology. Therefore, observation of the morphologic distribution of microvessels is one of the key points for many researchers in the field. Using diffraction enhanced imaging (DEI), we observed the mirocvessles with diameter of about 40 μm in mouse liver. Moreover, the refraction image obtained from DEI shows higher image contrast and exhibits potential use for medical applications.