After the midsummer, the medical examination season has arrived. With the improvement of physical examination items, low-dose high-resolution spiral CT of the chest has become one of the key physical examination items. After the physical examination, many people opened the examination report and saw the CT results prominently stating: "Pulmonary nodules, I couldn't help but take a cold breath. Is a nodule a tumor? Why is there a pulmonary nodule? Do you need to undergo surgery to remove it? "A series of questions urgently need to be answered correctly. Is pulmonary nodules fatal? Pulmonary nodules refer to a type of lesion that appears within the lung tissue, usually circular, irregular, and of varying density, often surrounded by normal lung tissue. The description of CT reports often includes increased density shadows in the lungs, clear or unclear boundaries, and even words such as burrs and lobes. According to the number of lesions, they can be divided into solitary pulmonary nodules, multiple pulmonary nodules, and diffuse pulmonary nodules. According to the density of nodules, they can be divided into solid nodules, pure ground glass nodules, and mixed ground glass nodules. The benign and malignant pulmonary nodules that the public is most concerned about are actually a pathological classification. Having a pulmonary nodule is not necessarily a lung tumor. According to the 2018 Chinese expert consensus on the diagnosis and treatment of pulmonary nodules, those with a diameter less than 5mm are defined as small nodules, and the likelihood of malignancy is less than 1%; A diameter of 5-10 millimeters is defined as a small pulmonary nodule, with a possibility of malignancy ranging from 25% to 30%; Tiny nodules and small nodules mostly only require regular follow-up, no intervention, and no surgical treatment. The follow-up period is generally six months to one year. A diameter of 10 millimeters to 30 millimeters is called a pulmonary nodule; A lung nodule larger than 30 millimeters is called a lump, and a lung nodule with a diameter greater than 20 millimeters has a malignant transformation rate of 64% -82%. Will pulmonary nodules disappear? After pulmonary infection, including but not limited to pulmonary tuberculosis and pulmonary fungal infection, pulmonary nodules may also appear after COVID-19. Some people also have pulmonary nodules caused by pulmonary hemangiomas. If it is a benign lesion, clinically common ones include pulmonary hamartoma, amyloidosis, lipoid pneumonia, etc. Asymptomatic respiratory infections may also affect the size changes of nodules. Outpatient doctors can consider antibiotic treatment (such as commonly used cephalosporins and quinolones in clinical practice) for 7-10 days when dealing with small nodules with pulmonary inflammatory shadows discovered during the first time of chest CT examination. If there are obvious inflammatory manifestations, it can be extended to 2 weeks. After 1-3 months, chest CT will be rechecked to see if the pulmonary nodules have disappeared. If the pulmonary nodules disappear after using antibiotics, that is the best news. If the old lesion nodules (showing calcification and high density on chest CT), especially high-density calcified nodules, do not require antibiotic treatment or surgical intervention. Regular follow-up is sufficient. According to the consensus of Chinese experts on the diagnosis and treatment of pulmonary nodules, it is currently not recommended to undergo surgery immediately after the first discovery of pulmonary nodules. In addition, follow-up examination after anti-inflammatory treatment is very important. What are the high-risk groups for lung cancer? The high-risk population for lung tumors includes: age ≥ 40 years old, a history of smoking for many years, long-term exposure to asbestos, beryllium, uranium, radon, and other environments, combined with chronic obstructive pulmonary disease, pulmonary fibrosis, or previous pulmonary tuberculosis, and a history of malignant tumors or tumor families for at least 5 years. There are no specific measures to prevent lung cancer. We should try our best to avoid high-risk occupational environments and avoid occupational exposure