After lung cancer is clearly diagnosed, the first thing that needs to be done is the staging diagnosis, because it is related to the next step of treatment. In the staging stage of clinical diagnosis, the most important thing is to judge through imaging, which requires enhanced CT of the chest, note that it is enhanced CT and enhanced MRI of the head, as well as enhanced CT of the upper abdomen and whole body bone scan, which are generally required. If economic conditions allow, PET-CT can also be done. The above imaging examinations are mainly to clarify how large the occupying lung lesions are, which adjacent organs they have invaded, and whether there are distant metastases, so that the evidence can be used to make a staging diagnosis, judge whether it is early or late, and guide the follow-up treatment.