Primary bronchial lung cancer (lung cancer for short) is one of the most common malignant tumors, and its incidence rate ranks first among urban malignant tumors. If the cancer has not yet spread, surgery to remove the cancer is the most common treatment for non-small cell lung cancer. If the cancer has spread and cannot be treated by surgery, radiotherapy and chemotherapy can be used alone or in combination to shrink the tumor and control the symptoms. Radioactive particle implantation is a kind of brachytherapy and has the advantages of: ① best and accurate shape irradiation ② high dose treatment to the target area of the tumor and high local control rate ③ protection of the surrounding normal tissues and low complications ④ easy to operate, etc. This method is the most common treatment for advanced lung cancer patients. This method provides a safe and effective clinical means to improve the quality of life and survival rate of advanced lung cancer patients. Radioactive particle implantation therapy refers to the implantation of micro radioactive particle source into the tumor or tissues infiltrated and invaded by the tumor, including the tissues where the tumor may spread through the lymphatic pathway, under the guidance of CT or B-ultrasound during the operation or according to the three-dimensional treatment plan. The low energy X-rays and γ-rays continuously emitted by the micro radiation source will act on the tumor continuously and continuously for 200 days, so that any tumor cells in the active stage will be inhibited and killed by the rays, thus the local tumor will be controlled most effectively, while the normal tissues will not be damaged or will only be slightly damaged. It provides an effective way for the treatment of middle and late stage lung cancer. Radioactive 125I particle brachytherapy for lung cancer is mainly used for advanced non-small cell lung cancer. According to different patients’ conditions, the position of particle implantation varies: for those who can be surgically resected, the “sandwich” method can be applied to implant in the tumor bed, which can achieve the purpose of preventing local recurrence; for those who can only be partially surgically resected, the particles can be implanted in the residual tumors; and for those who cannot be surgically resected, the particles can be implanted by percutaneous puncture or fibreoptic bronchoscopy, and so on. The main indications are poor lung function reserve, the lung tissue to be resected is more than the patient’s tolerance; the lesion is in the hilum and infiltrates the surrounding large blood vessels; the lesion extends to the mediastinum, trachea, esophagus, aorta, superior vena cava, or pericardium; the tumor invades the chest wall or spine, and it is impossible to completely remove it; the tumor is in the lumen of the central airway, and the tumor occupies the rondulet and the main airway lumen of the side of one side of the main bronchial lumen below the 1/2 of main tracheal lumen, the middle segmental tracheal lumen and the lobar bronchial lumen. The tumor is in the central airway lumen and occupies the rump and one side of the main bronchial lumen below 1/2 of the main bronchial lumen, the intermediate bronchial lumen, and the lobar bronchial lumen; the tumor diameter is less than 6 cm.