Editing Radiosurgery (section)

==Mechanism of action==
[[Image:Acoustic schwannoma gamma knife.jpg|right|thumb|Planning [[CT scan]] with IV contrast in a patient with left cerebellopontine angle [[vestibular schwannoma]]]]
The fundamental principle of radiosurgery is that of selective [[ionization]] of tissue, by means of high-energy beams of radiation. Ionization is the production of [[ion]]s and [[free radicals]] which are damaging to the [[cell (biology)|cells]]. These ions and radicals, which may be formed from the water in the cell or biological materials, can produce irreparable damage to DNA, proteins, and lipids, resulting in the cell's death. Thus, biological inactivation is carried out in a volume of tissue to be treated, with a precise destructive effect. The radiation dose is usually measured in [[Gray (unit)|grays]] (one gray (Gy) is the absorption of one [[joule]] of energy per kilogram of mass). A unit that attempts to take into account both the different organs that are irradiated and the type of radiation is the [[sievert]], a unit that describes both the amount of energy deposited and the biological effectiveness.{{cn|date=December 2021}}