Currently, the more common methods of clinical lung nodule classification include size, number, density, and type of pathology. 1. Size: Lung nodules can be categorized according to their diameter into tiny lung nodules (less than 5mm), small nodules (5~10mm), and pulmonary nodules (less than 30mm). 2. Number: Lung nodules can be categorized into isolated lung nodules and multiple lung nodules according to their number. 3. Density: Lung nodules can be categorized into solid nodules, mixed ground-glass nodules (partially solid nodules), and pure ground-glass nodules according to their density. 4. Pathologic type: they can be divided into benign nodules (e.g. tuberculosis ball, misshapen tumor, etc.) and malignant nodules (e.g. lung cancer, lung metastasis, etc.). If lung nodules are found, patients are advised to go to the hospital in time, improve the examination, and under the guidance of the doctor for treatment or regular follow-up.