Iodine 125 inter-tissue permanent implantation of radioactive particles for the treatment of tumors refers to the direct implantation of radioactive nuclides into or around the target volume of the tumor through imaging-guided technology (ultrasound, CT/MRI), and the killing of tumor cells through the continuous release of rays from the radionuclides, so as to achieve the purpose of treating tumors. Advantages of Iodine 125 particle implantation 1. Small surgical damage, implanted through surgery or percutaneous puncture. 2, less radiation to normal tissues, the diameter of radiation is only 1.7cm, which realizes precise radiation therapy and reduces the irradiated dose to normal tissues. Guo Zhizhong, Department of Medical Oncology, Henan Hospital of Traditional Chinese Medicine, Henan Province, China 3. High irradiation efficiency, continuous low-dose irradiation treatment can make the tumor cells with different division cycles in the tumor tissues get uniform irradiation. 4.Surgery is simple and easy, the optimal needle angle can be selected according to the size, shape, position and depth of the tumor. Under the guidance of CT, MRI or B ultrasound, the treatment plan is formulated through the treatment planning system (TPS), and the implantation quantity and distribution of the seed source are precisely calculated, which ensures the maximum killing of tumor tissues and at the same time protects the surrounding normal tissues and sensitive organs more effectively. Types of Tumors Treated 1.Head and Neck Tumors: Tongue Cancer, Nasal Smoke Cancer, Maxillary Sinus Cancer, Parotid Adenocarcinoma, Oropharyngeal Cancer, Tonsil Cancer. 2. Tumors of chest: esophageal cancer, lung cancer, breast cancer. 3.Gastrointestinal tract tumors: stomach cancer, liver cancer, pancreatic cancer, bile duct cancer, rectal cancer. 4.Neurological system tumor: glioblastoma. Genitourinary system tumor: prostate cancer, cervical cancer, endometrial cancer, vaginal cancer. Scope of application 1, untreated primary tumors, such as prostate cancer. 2, Tumors that need to retain important functional tissues or surgery will accumulate important organs, such as deep brain tumors. 3, Cases in which patients refuse radical surgery, such as thyroid cancer, cervical cancer, breast cancer. 4.Preventive implantation for preventing regional spread in local spread of tumor and enhancing radical effect. 5.Metastatic tumor foci or postoperative isolated tumor metastases, such as liver and lung multiple metastases. 6, inoperable primary cases: such as giant mass hepatocellular carcinoma, snuff cancer, etc. 7, Cases in which the effect of external irradiation is poor or failed, or the dose of external irradiation is insufficient, as the supplement of local dose. 8.The residual tumor or the cutting edge is too close to the tumor in the operation. 9, Palliative treatment for middle and late stage tumors.