Nodules in the lungs may be seen for the following reasons: 1. old lesions: especially after recovery from tuberculosis, there may be old lesions like lung nodules left behind, which can even be accompanied by nodule calcification. 2. benign tumors: for example, benign tumors like lung malignant tumors are relatively common. 3. nodular disease or pneumoconiosis: there are also special conditions that may be seen, including nodular disease, pneumoconiosis, etc. 4. malignant lesions: for example Early stage lung cancer can cause nodules in the lung, and metastatic lung cancer can also cause nodules in the lung. When lung nodules are found on chest CT, the features of chest CT and the characteristics of the patient’s disease, whether there is a family history of lung cancer, whether there is long-term smoking, etc. should be evaluated in detail, and then treated accordingly based on a comprehensive analysis of the relevant circumstances.