In recent times, the development of Western medicine has been more rapid, and medical testing methods have emerged in an endless stream. This has brought convenience to the diagnosis of diseases, but some diagnostic methods have also brought health hazards to the people’s health, and even cancerous effects. One of them is CT, an X-ray computed tomography invented in the 1970s, whose source is ionizing radiation, which, by its very nature, increases the mutation rate of human cells and increases the risk of cancer. The intensity of X-rays utilized in CT is higher than that of regular X-rays. Thin-layer CT is a diagnostic CT in the conventional imaging department that allows the introduction of CT-enhanced contrast agents, the enhancement of which is targeted at peripheral vascular imaging. Thin-layer scanning (1~5mm layer thickness and layer separation) compared to CT conventional scanning (10mm layer thickness and layer separation) layer thickness is thinner, scanning thin-layer CT can improve the detection rate of lesions, to avoid the omission of small lesions. It can be seen that although thin-layer CT detection is more accurate, but its radiation exposure is also significantly increased, if in a short period of time too often do thin-layer CT, indeed can increase the risk of cancer. This point must be clear, try to avoid doing thin layer CT, at least not frequently take thin layer CT such as examination. CT diagnosis because of its special diagnostic value, has been widely used in clinical. However, CT equipment is relatively expensive, the examination cost is high, certain parts of the examination, diagnostic value, especially qualitative diagnosis, there are certain limits, so it is not appropriate to consider CT examination as a routine diagnostic means, should be in the understanding of its advantages on the basis of a reasonable choice of application. x-ray radiography, CT, magnetic resonance imaging can be referred to as the troika, the three organically combined, so that the current imaging examination not only expanded the scope of the examination, but also Improved diagnostic level.