Journal of X-Ray Science and Technology - Volume Preprint, issue Preprint
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Journal of X-Ray Science and Technology is an international journal designed for the diverse community (biomedical, industrial and academic) of users and developers of novel x-ray imaging techniques. The purpose of the journal is to provide clear and full coverage of new developments and applications in the field.
Areas such as x-ray microlithography, x-ray astronomy and medical x-ray imaging as well as new technologies arising from fields traditionally considered unrelated to x rays (semiconductor processing, accelerator technology, ionizing and non-ionizing medical diagnostic and therapeutic modalities, etc.) present opportunities for research that can meet new challenges as they arise.
Abstract: Computed tomography (CT) plays an important role in digital rock analysis, which is a new prospective technique for oil and gas industry. But the artifacts in CT images will influence the accuracy of the digital rock model. In this study, we proposed and demonstrated a novel method to restore detector-unit-dependent functions for polychromatic projection calibration by scanning some simple shaped reference samples. As long as the attenuation coefficients of the reference samples are similar to the scanned object, the size or position is not needed to be exactly known. Both simulated and real data were used to verify the proposed…method. The results showed that the new method reduced both beam hardening artifacts and ring artifacts effectively. Moreover, the method appeared to be quite robust.
Abstract: Monochromatic-beam-based dynamic X-ray computed microtomography (CT) was developed to observe evolution of microstructure inside samples. However, the low flux density results in low efficiency in data collection. To increase efficiency, reducing the number of projections should be a practical solution. However, it has disadvantages of low image reconstruction quality using the traditional filtered back projection (FBP) algorithm. In this study, an iterative reconstruction method using an ordered subset expectation maximization-total variation (OSEM-TV) algorithm was employed to address and solve this problem. The simulated results demonstrated that normalized mean square error of the image slices reconstructed by the OSEM-TV algorithm was…about 1/4 of that by FBP. Experimental results also demonstrated that the density resolution of OSEM-TV was high enough to resolve different materials with the number of projections less than 100. As a result, with the introduction of OSEM-TV, the monochromatic-beam-based dynamic X-ray microtomography is potentially practicable for the quantitative and non-destructive analysis to the evolution of microstructure with acceptable efficiency in data collection and reconstructed image quality.
Abstract: In practice, mis-calibrated detector pixels give rise to wide and faint ring artifacts in the reconstruction image of the In-line phase-contrast computed tomography (IL-PC-CT). Ring artifacts correction is essential in IL-PC-CT. In this study, a novel method of wide and faint ring artifacts correction was presented based on combining TV-L1 model with guided image filtering (GIF) in the reconstruction image domain. The new correction method includes two main steps namely, the GIF step and the TV-L1 step. To validate the performance of this method, simulation data and real experimental synchrotron data are provided. The results demonstrate that TV-L1 model with…GIF step can effectively correct the wide and faint ring artifacts for IL-PC-CT.
Abstract: Based on X-ray diffraction (XRD) pattern of coal, an empirical model for judging the coalification degree is used to calculate the ratio of the 002 peak height to the Full width at half maximum (FWHM). However, the existing models are often simpler and more suitable for judgment of the medium and low rank coal, while are not feasible in determination of high rank coal. In order to address this issue, the objective of this study is to establish a new modified mathematical model based on optimization of the existing empirical models. Through the calculation of Bragg equation, it demonstrates that…the low-angle region (2θ = 3–10°) in the XRD pattern reflects the information of micropore in coal with a diameter of (0.884–2.94) nm. Accordingly, its diffraction intensity corresponds to the porosity rate in coal. As a result, the modified mathematical model has been established for characterizing the coalification degree by introducing the variation of porosity rate with the coal ranks creatively. The synergistic effects of the change regulation of organic matter peak and the porosity rate with coal rank ensure the accuracy of the model. Furthermore, the good stability and high reliability of new model are verified through the recalculation of a total of 14 coal samples. Study results demonstrated that the new method enabled to determine coal rank more conveniently and accurately in the industrial production.
Abstract: Double aortic arch (DAA) is a rare congenital anomaly associated with the formation of a vascular ring. Patients with DAA commonly suffer from complications caused by intracardiac and extracardiac malformations and different degrees of airway stenosis. Multislice computed tomographic angiography (MSCTA) is an intuitive and effective medical imaging technique in clinical diagnosis of DAA. MSCTA can accurately manifest the aortic arch and the course of the descending aorta and airway stenosis in three-dimension (3D). It is important to diagnose and make an operative plan for DAA. In this paper, we present a case of DAA diagnosed by MSCTA with 3D-static…images and rotated reconstruction images and performed a mini-review.
Keywords: MSCTA, 3D reconstruction images, double aortic arch, diagnosis