Clinical diagnosis is made by imaging, which can show different imaging features for pneumonia and lung cancer, for example, by double lung radiographs, CT or MRI. Pneumonia may appear as patchy, diffusely distributed, or localized dense, dense shadows with relatively uniform density increase, and may appear as foci of inflammatory invasion. The lesions do not pull on the surrounding tissues and are well defined from the surrounding soft tissues. Lung cancer may appear as a high-density solid mass with irregular cavities and burrs of different sizes, irregular shape, unsmooth edges, and unclear demarcation with surrounding normal lung tissues, and dynamic metastatic lesions with relatively rapid spread.