Current Issue : October - December Volume : 2014 Issue Number : 4 Articles : 4 Articles
Current computed tomography (CT) scanners rotate fast to reduce motion artifact. X-ray tube must work in a high power to make\nthe image clear under short exposure time. However, the life span of such a tube may be shortened. In this paper, we propose a\nnovel double sources CT imaging system, which puts two of the same X-ray sources closely with each other.The system is different\nfrom current dual source CT with orthogonal X-ray sources. In our system, each projection is taken twice by these two sources to\nenhance the exposure value and then recovered to a single source projection for image reconstruction. The proposed system can\nwork like normal single source CT system, while halving down the working power for each tube...
Monte Carlo simulations were used to study photon production in a panoramic X-ray tube with a conical tungsten target to\ndetermine the optimal characteristics of the target shape and electron beam configuration. Several simulations were performed\nfor accelerating potentials equal to 250 kV, 300 kV, and 500 kV with electron beams of various radii and anode sizes. The angular\ndistribution of the photon intensity was analysed by numerical calculations for an assembly composed of an X-ray tube and an\nexternal collimator with a cylindrical hole to simulate a panoramic scanning system with an X-ray pencil beam....
Currently industrial X-CT system is designed according to characteristics of test objects, and test objects determine industrial\nX-CT system structure, X-ray detector/sensor property, scanning mode, and so forth. So there are no uniform standards for the\ngeometry size of scintillation crystals of detector.Moreover, scintillation crystals are usually mixed with some highly toxic impurity\nelements, such as Tl and Cd.Thus, it is indispensable for establishing guidelines of engineering practice to simulate X-ray detection\nperformances of different scintillation crystals. This paper focuses on how to achieve high efficient X-ray detection in industrial XCT\nsystem which usedMonte Carlo (MC) method to study X-ray energy straggling characteristics, full energy peak efficiency, and\nconversion efficiency of some scintillation crystals (e.g., CsI(Tl),NaI(Tl), andCdWO4) afterX-ray interacted with these scintillation\ncrystals. Our experimental results demonstrate that CsI(Tl) scintillation crystal has the advantages of conversion efficiency, spectral\nmatching, manufacturing process, and full energy peak efficiency; it is an ideal choice for high efficient X-ray detection in industrial\nX-CT system....
We construct a medical X-ray direct digital radiography (DDR) system based on a CCD (charge-coupled devices) camera. For the\noriginal images captured from X-ray exposure, computer first executes image flat-field correction and image gamma correction,\nand then carries out image contrast enhancement. A hybrid image contrast enhancement algorithm which is based on sharp\nfrequency localization-contourlet transform(SFL-CT) and contrast limited adaptive histogramequalization (CLAHE), is proposed\nand verified by the clinical DDR images. Experimental results show that, for the medical X-ray DDR images, the proposed\ncomprehensive preprocessing algorithm can not only greatly enhance the contrast and detail information, but also improve the\nresolution capability of DDR system....
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