γ射线刀是指应用放射线选择性破坏(照射)颅内靶部位的方法,又称放射外科学。此方法1968年首先由Leksell开发利用,其目的是用射线造成小的破坏灶来代替脑手术,以治疗功能性疾病。1970年Steiner报道该法治疗脑动静脉畸形有效,此后逐渐应用于各种血管畸形和脑肿瘤。目前,γ射线刀作为脑的深部和脑干部无法手术的脑动静脉畸形等的治疗方法,已引起了人们的关注。γ射线刀装置是在球面上分散配置201个~(60)Co射线源,每个射线源发出的γ射线经各自的准直器限束形成细的线束,并在球心区聚成焦点。将患者头部固定在此装置内,使颅内病变区重合在γ射线的焦点区进行放射。此法与以往的定位脑手术相同,用专用固定架固定头颅,进行血管造影、CT或MR1检查,确定病变的三维座标。然后利用相同固定架,将头部固定在γ射线刀装置内,确保精确度在0.3mm以下。该装置的深部线量构成特点是线量呈高度集中,其外侧线量很少。照射时,以单次大量照射为原则,中心线量通常为35～50Gy,其效果高出以往分次照射的3倍左右。经照射的靶区几呈球状破坏,界限明确。准直器直径有4、8、14、18mm 4种类型,可根据靶部位的大小选用。对不规则形的病变,可组合应用 Gamma-ray knife is a method of selectively destroying (irradiating) intracranial target sites with radiation, also known as radiosurgery. This method was first developed and used by Leksell in 1968. Its purpose was to use radiation to cause small lesions to replace brain surgery to treat functional diseases. In 1970, Steiner reported that this method is effective in the treatment of cerebral arteriovenous malformations, and has since been gradually applied to various vascular malformations and brain tumors. At present, gamma ray knife has attracted people’s attention as a treatment method for cerebral arteriovenous malformations that cannot be operated in the deep brain and brain stem. The γ-ray knife device is equipped with 201~60 Co ray sources dispersedly arranged on the spherical surface. The gamma rays emitted from each ray source are bundled by the respective collimators to form a thin wire harness, and are focused in the center of the sphere. The patient’s head is fixed in this device so that the intracranial lesion overlaps the gamma ray’s focal region for radiation. This method is the same as previous localization brain surgery. The head is fixed with a special fixation frame to perform angiography, CT or MR1 examination to determine the three-dimensional coordinates of the lesion. Then use the same holder to fix the head in the γ-ray knife device to ensure the accuracy is less than 0.3mm. The feature of the deep line quantity of the device is that the line quantity is highly concentrated and the amount of outside line is very small. During irradiation, the principle of a large number of single irradiation, the center line volume is usually 35 ~ 50Gy, the effect is higher than the previous fractional irradiation about 3 times. The irradiated target area was spheroidically destroyed with clear boundaries. There are four types of collimator diameters: 4, 8, 14 and 18mm, which can be selected according to the size of the target part. For irregular shaped lesions, can be combined application