Diagnostic process of lung cancer: 1. Clinical symptoms: only prove the presence of disease. 2.Signs: only prove the presence of disease. 3.Imaging: suggests the specific location and size of lesion, including: chest fluoroscopy; chest plain film; chest CT; PET/CT and other examinations. 4.Cytological diagnosis: can be treated, including: sputum exfoliative cytology (morning sputum or post-microscopic sputum); fiberoptic bronchoscopy brushing; percutaneous pulmonary puncture, etc. 5.Pathological histological diagnosis: treatable, including: fiberoptic bronchoscopy biopsy; percutaneous lung aspiration biopsy; lumpectomy biopsy; dissecting thoracic exploration tumor biopsy; surgical resection specimen examination, etc.