To Establish a Molecular Typing System for Early Diagnosis of Lung Cancer

1. All patients underwent low-dose CT pulmonary nodule AI detection and peripheral blood ctDNA methylation detection at baseline 2. Follow-up plan: Low-risk and medium-risk nodules and some high-risk nodules (5-10mm) were followed up. 10ml peripheral blood was collected from each follow-up and stored for testing until the end of the study. The high-risk nodules over 10mm were evaluated by the expert group and the patients were informed by biopsy or surgical resection. Histopathological diagnosis was made and compared with ctDNA methylation results to analyze the sensitivity and specificity of ctDNA methylation markers of lung cancer. 3. Endpoint: Tissue samples were pathologically diagnosed as benign or malignant.