1. Hemoptysis of unknown origin or chronic irritant cough. 2.Presentation of bronchial obstruction, such as limited croup, limited emphysema, obstructive pneumonia or any pulmonary atelectasis. 3.Suspected tracheal and bronchial tumors. 4.Unexplained paralysis of the recurrent laryngeal nerve or phrenic nerve. 5.Cancerous cells found in sputum or Mycobacterium tuberculosis found, but no lesion found in chest X-ray. 6.Suspected bronchial foreign body, stone. 7.Diffuse lung lesions or peripheral lung masses that require lung biopsy, brushing or lavage for cytology or bacteriology to make a clear diagnosis. 8, Chest radiographs with infiltrative lesions of unknown origin. 9, Collection of lower respiratory secretions for bacteriological examination. 10.Bronchoalveolar lavage, bronchial drug delivery and aspiration therapy. 11.Patients with long-term indwelling cannula after tracheotomy to know whether there is any damage and necrosis in their trachea. 12.Lung hilar enlargement, lung masses of unknown origin. 13.Iodine oil or iodine water imaging of a selected lung lobe or lung segment.