**5. Stereotactic radiosurgery**

SRS is a leading alternative to surgery or embolization, especially for AVMs located in deep or eloquent brain regions, where invasive treatment is not optional [79]. SRS employs ionizing radiation for gradually occluding AVM blood vessels. Its application was adopted from oncology during 1970–1980s [80, 81]. During the next decades, SRS (or "gamma-knife") rapidly evolved as a standalone modality and following embolization. SRS systems typically comprise a spherical array of high-focused gamma ray generators (**Figure 5**), a mechanical system that precisely positions and immobilizes patients' heads and a 3D imaging, and tracking system for treatment (i.e., dose delivery) design and real-time management (**Figure 6**). The chief benefit of radiosurgery is that it can eliminate the threat of spontaneous intracranial hemorrhage by gradual obliteration of the AVM over 2–3 years [81].
