论文部分内容阅读
本讲首先讨论X-CT的成象原理,简述成象装置的发展过程,接着重点讨论X-CT图象重建方法;最后,就X-CT的噪声问题及临床应用作简要的介绍。一、X射线计算机断层成像的基本原理 1.基本扫描系统的组成及工作原理图3.1表示X-CT的基本扫描系统。X射线源首先经过准直器,形成一很细的射线束,再透过人体的受检层面。透射过去的X射线光子被每一位置上的扫描检测器所测量。射线源和检测器首先作平行移动,待射线扫过受检体后,再转一小角度重复平移扫描,直至旋转180°角为止。这样,检测器就可获得各个方向上的多个投影数据。这些数据反映
This lecture first discusses the imaging principle of X-CT, briefly describes the development of imaging device, and then focuses on the X-CT image reconstruction method. Finally, it gives a brief introduction about the noise and clinical application of X-CT. First, the basic principles of X-ray computed tomography 1. Basic scanning system components and working principle Figure 3.1 shows the basic scanning system X-CT. X-ray source first through the collimator to form a very thin beam, and then through the human body examined level. The transmitted X-ray photons are measured by the scanning detector at each location. Radiation source and detector first of all for a parallel movement, until the rays swept through the subject, and then repeat a small angle translation scan until rotated 180 ° angle so far. In this way, the detector can obtain multiple projection data in all directions. These data reflect