I. Overview In the diagnosis of lung diseases, diagnostic imaging plays a key role. For some lesions that are still difficult to diagnose clearly by imaging, further cytological or histopathological examinations are often required to assist clinicians in selecting the correct treatment plan, especially for tumorigenic lesions such as lung cancer. Even if the diagnosis of lung cancer can be basically confirmed by imaging, it is recommended to make the diagnosis of histopathological classification and staging as much as possible, so as to select the appropriate diagnostic and therapeutic means – surgical resection treatment, radiotherapy, chemotherapy, molecular targeted drugs and other diagnostic and therapeutic means. In the case of peripheral lung cancer that has not invaded the larger bronchi, fiberoptic bronchoscopy is negative in some patients, and the diagnosis cannot be confirmed. Therefore, in the diagnosis and differential diagnosis of lung cancer, percutaneous thoracic needle aspiration biopsy plays a special role. Percutaneous lung tumor aspiration biopsy is currently an important method to obtain cytologic and histologic diagnosis of lung cancer. It is especially important for early diagnosis, histological classification and clinical staging of lung cancer. Indications for percutaneous thoracic tumor biopsy The indications for percutaneous biopsy technique are relative and should be based on the degree of disease diagnostic needs and combined with the patient’s specific conditions. The general indications are as follows: 1.Lung lesions that cannot be diagnosed by common clinical means (e.g. sputum cytology, fiberoptic bronchoscopy); 2.Pulmonary primary tumors that require histological classification for treatment selection; 3.Metastatic tumors in the lung that require identification of the source of the metastatic tumors; 4.Nodular lesions in the lung that are difficult to differentiate between lung cancer, tuberculosis and inflammatory pseudotumors; and 5.Pleural masses and chest wall masses; 6.Mediastinal masses or enlarged mediastinal clinopalatine nodes, which need to be understood in relation to lung cancer; 7.Diffuse lung lesions of unknown etiology, especially those with simultaneous parenchymal interstitial involvement. Patients with severe emphysema and pulmonary heart disease, which are difficult to tolerate due to severely impaired pulmonary function; 2. Patients with pulmonary alveoli or pulmonary capsular bells in the path of needle puncture, which have a significantly increased possibility of causing pneumothorax; 3. Patients with uncontrollable violent coughing and wheezing, in which puncture is very likely to injure the pleura leading to bleeding and pneumothorax; 4. Patients with lesions considered to be vascular, such as intrathoracic aneurysm, arteriovenous malformation, etc; 5.Patients with serious bleeding tendency or coagulation dysfunction. The common complications of percutaneous thoracic tumor puncture biopsy are as follows: pneumothorax, hemoptysis, local bleeding.