Intrastromal radiotherapy is a radiotherapy method that uses multiple closed radiation sources with certain specifications and activity, which are applied directly to human tissues in a minimally invasive manner to irradiate tissues at high doses to achieve the purpose of tumor treatment. Advantages: 1.Improve target dose, reduce radiation damage and complications 2.Incessant irradiation to tumor cells of different division cycles, with high radiobiological effect and increased radiosensitivity of lesions 3.3D design + navigation/stereotactic technology, which can realize optimized and individualized radiotherapy design requirements 4.Simple operation and small trauma Mechanism of action: After the radioactive source is implanted into the body, the characteristic photons and electrons are used to treat the tumor. After the source is implanted, the characteristic photons and electrons are excited and absorbed after the electron capture decay; the photons mainly emit 36kev r-rays continuously, and the r-rays have direct effects on the DNA molecular chain: single-strand breakage and double-bond breakage. r-rays have indirect effects: ionization of water molecules and generation of free radicals, which interact with biological macromolecules and cause tissue cell damage, resulting in the loss of tumor cells’ reproductive capacity and apoptosis. Indications for intra-stromal radiotherapy: 1. Pathologically confirmed malignant tumor. 2. Age: 18-70 years old. 3. Karnofsky behavior score (KPS): 70 or above. 4. CT and MRI enhancement scan showed that the maximum diameter of tumor is less than 6cm and the contour is clearer. 5. Those with recurrent malignant tumor (KPS > 60 points, tumor less than 5cm, no brainstem and corpus callosum involvement).