The incidence of intracranial tumors ranks eighth among tumors, among which neuroepithelial tumors, meningiomas, nerve sheath tumors, neurofibromas, germ cell tumors and metastases are the main ones, the first three of which reach 80%. It is mainly used for inoperable and sensitive tumors, such as germ cell tumors, metastases, and some neuroepithelial tumors with higher malignancy; secondly, it is used to prevent tumor recurrence after surgery, and most of the neuroepithelial tumors, meningiomas and nerve sheath tumors need radiation therapy after surgery, including astrocytomas, glioblastoma, ventricular canal, pituitary tumors, etc.; thirdly, it is to create surgery opportunity again for inoperable tumors with larger volume, and make the tumor shrink through radiation therapy. The third one is to create the opportunity of surgery again for inoperable tumors of large size, and make the tumor shrink, partially occlude blood vessels, reduce intraoperative bleeding, and reduce the risk of surgery, such as larger meningioma and hemangioma; radiotherapy treatment is divided into general radiotherapy, three-dimensional conformal radiotherapy, and stereotactic radiosurgery (X-knife, γ-knife). The three radiotherapy methods have their own indications. Rational selection of stereotactic radiosurgery (X-knife, γ-knife): it is used for patients who have less than 3 cm of direct longitudinal, less than 3 brain metastases, local residual after surgery of malignant brain tumor or cannot be operated due to tumor site, size and patient’s physical condition, and also for some patients who have less than 3 cm of direct longitudinal It is also used for the treatment of benign tumors smaller than 3cm, and for increasing the radiation dose locally after general radiotherapy in order to achieve the purpose of radical treatment of tumors. Three-dimensional conformal radiotherapy: It is used for brain metastases larger than 3cm, inoperable primary tumors, local residual tumors after surgery and well differentiated tumors such as glioma, pituitary tumor, astrocytoma, etc., partly for radical treatment and partly for preventive treatment to prevent recurrence after surgery. General radiotherapy for the whole brain: it is used for poorly differentiated gliomas, brain metastases, germ cell tumors and medulloblastomas with higher malignancy, etc. It is mostly a palliative treatment to relieve patients’ clinical pain; the indications for the three methods are different. Key factors of radiotherapy effect 1. Precise positioning: In other words, before treatment, the location, size, shape and three-dimensional spatial structure of the tumor, the surrounding important organs, etc. are accurately determined by some special equipment, and the shape of the irradiation field, the important organs to be protected, and the direction of the irradiation field are delineated. The methods to achieve precise positioning mostly use cephalic membrane fixation, using special methods to fix the head to the unique device, one is to achieve precise positioning, the second is to have the same position for each treatment, and the third is to avoid marking the positioning line directly onto the patient’s head and facial skin to achieve the cosmetic effect. 2.Precise planning: Different kinds of intracranial tumor treatment methods, radiation dose and equipment used are different, so detailed and careful planning should be made before treatment. In general, the dose is 1.5~1.8 Gy each time, but the dose for 3D conformal is 2.0~2.5 Gy each time, and the dose for X-knife and γ-knife is 6~20 Gy, so it is necessary to plan well before treatment. 3.Precise treatment: radiation therapy requires 20-30 times of treatment to be completed, and the body position, position, dose and machine parameters must be the same in each treatment, especially X-knife, γ-knife or three-dimensional conformal treatment must be the same each time, so that the irradiation dose to the tumor area is the same in each treatment, and finally the required treatment dose is achieved while the surrounding normal tissues are little irradiated. In order to achieve the required treatment dose with little irradiation to the surrounding normal tissues, so as to eliminate the tumor and avoid the damage to normal tissues at the same time.