Stereotactic radiosurgery uses all except:

Electron [Ret Perez and Brady's principles and practice of radiation oncology By Edward C. Halperin, 5/e p378; Sterotactic radiosurgery and radiotherapy are techinques to administer precisely directed, high-dose irradiation that tightly conforms to an intracranial target to create a desired radiobiologic response while minimizing radiation dose to surrounding normal tissue. (Stereotactic refers to using a precise three-dimensional mapping technique to guide a procedure). Stereotactic radiosurgery is an impoant alternative to invasive surgery, especially for tumors and blood vessel abnormalities located deep within or close to vital areas of the brain. Stereotactic radiosurgery works in the same way as other forms of radiation treatment. It does not actually remove the tumor; rather, it damages the DNA of tumor cells. As a result, these cells lose their ability to reproduce. When treated with radiosurgery, aeriovenous malformations (AVMs) begin to thicken and close off slowly, typically over several years. In the case of radiosurgery, all of the irradiation is done in a single session or fraction, while in stereotactic radiotherapy, more than one fraction of irradiation is administered. There are three basic kinds of stereotactic radiosurgery equipment, each of which uses different instruments and sources of radiation: The Gamma Knife(r) uses beams of highly focused gamma rays all aiming at the target region. Linear accelerator (LINAC) machines, prevalent throughout the world, deliver high-energy x-rays, also known as photons. (brand names such as Novalis TxTM, XKnifeTM, and CyberKnife(r).) Proton beam or heavy-charged-paicle radiosurgery- Proton beam offers ceain theoretical advantages over other modalities of stereotactic radiosurgery because it makes use of the quantum wave properites of protons to reduces doses to surrounding tissue beyond the target to a theoretical minimum of zero. In practice, the proton facility offers advantages for the treatment of unusually shaped brain tumors and aeriovenous malformations