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断层(Tomography)技术是X射线诊断学和核医学中获得人体截面图象的重要技术之一。七十年代以前,主要利用“聚焦平面”(Focal Plane)原理得到某一聚焦平面上的截面图象。该技术的主要缺点是,聚焦平面外的邻近平面对图象有干扰,因而成象后影象比较模糊。七十年代以后,发展了一种计算机断层(Computed Tomography简称CT)技术,完全根除了邻近平面对图象的影响,改善了影象的质量。1972年第一台X线计算机断层机开始用于临床,此后在世界各国得到相当程度的普及。与此同时,发射型计算机断层也得到了发展。但由于技术上的困难,使得发射型CT比X线CT(简称XCT)的发展稍晚一些。XCT主要利用X射线穿射人体时,
Tomography (Tomography) technology is one of the important technologies for obtaining body cross-sectional images in X-ray diagnosis and nuclear medicine. Before the seventies, the Focal Plane principle was used primarily to obtain a cross-sectional image of a focal plane. The main disadvantage of this technique is that the neighboring planes of the focused out-of-plane interfere with the image and hence the image is blurred. Since the 1970s, Computed Tomography (CT) has been developed to completely eliminate the influence of adjacent planes on the images and improve the image quality. In 1972 the first X-ray computed tomography machine began to be used clinically and has since enjoyed a considerable degree of popularity in all countries in the world. At the same time, launch computed tomography has also been developed. Due to technical difficulties, however, the launch CT is slightly later than the development of X-ray computed tomography (XCT). XCT X-ray radiation mainly through the human body,