Treatment can be divided. For large cerebral arteriovenous malformations (AVMs), endovascular embolization should be the first clinical option. Although embolization may not solve the whole problem, partial embolization can reduce local blood flow and lower the pressure in the nests of the malformed vessels, which is helpful in reducing bleeding. If little or no embolization is possible for various reasons, and because partial embolization often does not significantly reduce the volume of the entire AVM, it does not help much in the design of the Gamma Knife treatment plan. In order to improve the efficacy of Gamma Knife treatment and minimize side effects, it is best to give segmentation treatment at this time, usually using lesion volume segmentation, or therapeutic dose segmentation. Lesion volume segmentation: The AVM is artificially divided into two parts according to the course of the draining veins, the shape of the lesion, and the surrounding important structures, and is treated in two sessions (Figures 1 and 2). The interval between the two treatments is usually no more than 6 months. Treatment dose splitting: i.e., 50% isodose curve to encompass the lesion in its entirety, with a marginal dose of 12 Gy~15 Gy and a central dose of 24 Gy~30 Gy. The second treatment is performed after 6 months, with the same prescribed dose as before, or the dose is adjusted as appropriate.