普通X线摄影检查，是将透过人体的X线直接在涂有感光物质的胶片上成像。与此有本质不同的是，CT图像是X线扫描人体某一层面然后测得该层面中各点吸收X线的数据，再由计算机处理及图像重建，得到该层面的横断面图像。也就是说，CT图像是经计算机处理的人体各部位图像。这样一来 Ordinary X-ray examinations are performed by imaging the X-rays of the human body directly on a film coated with a photosensitive material. Essentially different from this, the CT image is X-ray scanning of a certain level of the human body and then measured the X-ray absorption data at each point in the layer. Computer processing and image reconstruction are then used to obtain a cross-sectional image of the layer. That is, the CT image is a computer-processed image of each part of the human body. Thus