Whether a lung nodule of 18mm is a tumor or not can only be diagnosed after a series of examinations, and no conclusion should be made blindly. Usually, the diameter of lung nodules <10mm lung nodules are called small nodules, such nodules if not hairy glass-like nodules, usually only need regular review can be. However, when the lung nodule exceeds 10mm, it is a larger nodule and should be taken seriously. At this point, the patient should go to the hospital for a series of imaging examinations chest X-ray, bronchoscopy and lung tissue aspiration biopsy, along with the patient's personal history and related clinical examination to clarify the nature of the tumor. If the tumor is benign, it is recommended to perform surgical resection as soon as possible. If it is malignant, it is recommended to perform surgery along with radiotherapy and chemotherapy, and the specific treatment plan is recommended to be carried out under the guidance of the doctor.