Fiberoptic bronchoscopy technique is an important treatment technique for chest diseases and an important examination item in the diagnosis of lung cancer. Through bronchoscopy, normal or abnormal conditions in the trachea and bronchial lumen can be visualized, and then biopsies, brushes, tissues and secretions can be obtained for bacteriological and histological laboratory examinations of lesions or suspected lesions. It can not only help to diagnose and determine the lesion site, understand the many abnormal changes caused by the cancerous foci when they invade the bronchial tree, but also provide a reliable theoretical basis for the selection of surgical methods and, at the same time, the treatment of local lesions. At present, fiberoptic bronchoscopy has become a very important tool in the diagnosis and treatment of lung cancer. For tumors located in the proximal airways, the positive rate of brushing and biopsy via fiberoptic microscopy reaches 90-93%, and for lesions located in the distal airways that cannot be directly detected by fiberoptic microscopy, lesions of lung tissue can be performed via fiberoptic microscopy under the guidance of fluoroscopy. Biopsy, with a positive diagnostic rate of 25-65%, can also be performed by transbronchial needle aspiration to obtain histological fluid for pathological examination. In addition, biopsy can be performed by endobronchial staining followed by biopsy to improve the positive rate of early diagnosis. PET-CT examination is needed for the following four types of patients: 1. Patients whose existing information is difficult to clearly diagnose malignant tumor and difficult to identify benign and malignant tumor: the important feature of tumor tissue is rapid growth and high metabolism, which shows high uptake in PETCT, if there is no metabolic increase performance, it suggests that benign lesion is more likely. Especially, other detection means can be considered when the nature of tumor is difficult to determine. 2. Patients with staging difficulties: PET can perform whole body tomographic imaging at one time, which is not possible with other imaging devices. In addition to detecting the primary lesion, it can also detect whether there is metastasis in other parts of the body, which is very helpful to the staging of tumor. 3.Patients who are difficult to judge whether they have recurrence: PET-CT can identify tumor recurrence at an early stage and re-stage tumor: PET can make early diagnosis of tumor residue or recurrence after treatment and differentiate it from fibrosis and necrosis after treatment, as well as re-stage according to the distribution of lesions after treatment, which is difficult to do by structural information-based imaging means such as CT and MRI. 4.Difficulty in diagnosing the primary foci of malignant tumors: The rapid whole-body PET/CT scan is used to find the primary foci for unexplained metastatic tumors with semi-quantitative effect.