Chest radiographs are the most important way to detect pneumothorax and diagnostic chest, in the case of pneumothorax, there is a significant increase in translucency beyond the pneumothorax line, and the lung texture is not visible. 1. Sometimes the pneumothorax is not so clear, you can let the patient exhale when the volume of the lung shrinks, then the density of the lung will increase, forming a clear contrast with the outside pneumothorax translucency, which is conducive to the detection of pneumothorax. 2. When there is a large amount of pneumothorax, the lung will retract toward the lung door, and the outer edge will be curved or lobulated, which should be distinguished from the central type of lung cancer.