With the increase of public attention to their own health, more and more people start to have health checkups. Is it true that the chest x-ray in the checkup program can exclude lung cancer if no abnormality is detected? Chest X-ray is not useful for screening early lung cancer! Chest X-ray has two fatal flaws in screening early stage lung cancer: 1. low resolution, difficult to find tiny lesions. 2. 2. There are dead ends, and it is difficult to detect lesions in the apical part of both lungs, near the mediastinal plane and the bottom of both lungs. Therefore, the medical community recommends low-dose spiral CT to screen for early stage lung cancer, which allows patients to receive lower doses of radiation than ordinary CT. The following groups of people are recommended to be screened for lung cancer: 1. smokers who smoke more than 20 cigarettes per day, long-term smokers who have smoked for more than 20 years, aged 55 and their family members 2. housewives 3. long-term living in air pollution environment, aged more than 45 4. high-risk occupations such as exposure to gas, asphalt, coking, dust, mining, chemical 5. previous lung-related diseases: tuberculosis, old and slow bronchial, bronchiectasis 6. tumors Family history