Clinically, pulmonary blisters, emphysema and lung cysts can cause 9mm round translucent shadow in the lower lobe of the right lung, which is a non-serious situation. 1. Lung blisters: if the diameter of the lung blisters is 9mm, the volume is small, belongs to the small lung blisters, patients often have no clinical symptoms, no treatment, regular review can be, belongs to the non-serious. 2. Emphysema: emphysema 9mm, belongs to limited emphysema, often patients also have no obvious clinical symptoms, no treatment, regular review can be, is also not serious. 3. Lung cysts: lung cysts 9mm, belong to benign lesions, small size, often no symptoms, can be observed and treated, not serious. Patients usually have discomfort, timely to the hospital, do not be careless, so as not to delay treatment.