Gamma knife treatment of brain diseases is a high-tech method requiring very strict requirements, scientific planning of treatment dose and implementation of individualized treatment is the core and key to successful treatment. The precise formulation of the coordinates of the target point of the lesion, the reasonable matching of the γ-line dose and curve rate, the choice of the collimator’s large and small caliber, the establishment of the real-shaped package image and the treatment prescription are the whole process that must be carefully designed and carefully planned without any negligence and carelessness. After the program is developed, it should be repeatedly revised and verified, and then two physicians should discuss and sign together before the treatment can be started. Only in this way can we ensure that there is nothing wrong and avoid complications. These principles must always be kept in mind by physicians who perform gamma knife surgery.
In developing the dose planner must be familiar with the fact that γ-knife surgery is a focused radiation of γ-rays to the target lesion, causing double-strand breaks in the DNA of the tissue cells in the area, resulting in proliferative necrosis of the cells. Therefore, the degree of tissue destruction is closely related to the size of the dose time curve, the dose is large necrosis occurs in a short time, and vice versa is long; the degree of tissue destruction is consistent with the size of the collimator, the larger the postoperative response is more obvious, the longer the duration; the postoperative occurrence of cerebral edema is mainly due to the γ-ray caused by the BBB opening resulting in plasma protein extravasation, the larger the γ-ray dose the shorter the latency period, the more significant edema changes; postoperative The occurrence of complications is closely related to the scientific nature of dose planning, and the dose should be deployed according to the patient’s condition and disease characteristics, and the dose is too large or small is inappropriate and undesirable. Therefore, it should be repeatedly emphasized that the treatment of any intracranial lesion with γ knife must be based on: 1, the nature of the lesion (benign or malignant); 2, the anatomical site (deep, shallow, functional area); 3, the volume of the lesion (large and small); 4, the clinical condition (good and poor); 5, the dose, histogram matching; 6, the dose of adjacent structures; 7, the previous radiation and chemotherapy; 8, the patient’s tolerance. These 8 items are analyzed together before a very appropriate prescription can be issued. When the dose is selected, especially remember that the amount given at each point, the volume received, the bull’s eye point, the peripheral volume and rate of decline, and the dose overlap rate should be carefully converted to make a scientific optimal plan to achieve the ideal treatment purpose.
Therefore, we advocate to give sufficient lethal destructive dose to the focal tissue, and also try to reduce or decrease the irradiated volume of the peripheral tissues and minimize their mutual overlap volume. Multiple small collimators and multiple isocenter dosing methods should be used more often to administer treatment in order to achieve good results and minimize complications. complications after γ-knife surgery occur because of: ① treatment of lesions with too large volume; ② excessive irradiation dose (large isocenter number with uneven dose); ③ abnormal sensitivity of individual patients to radiation.