{"entity":{"id":"radiosurgery-srs","kind":"technology","name":"Stereotactic radiosurgery (Gamma Knife, CyberKnife, linac SRS)","aka":[],"tldr":"A single very high dose, or a few doses, aimed at a small brain or spine target with millimetre precision, replacing whole-brain radiotherapy for most brain metastases.","summary":"Lars Leksell treated the first patients with the Gamma Knife in 1968 using converging cobalt-60 beams; today the same idea is delivered by dedicated Gamma Knife units, the robotic CyberKnife and conventional linacs fitted with fine collimators and image guidance. Radiosurgery treats brain metastases, meningiomas, vestibular schwannomas, arteriovenous malformations and, increasingly, spinal metastases. Randomised trials showed that treating brain metastases with radiosurgery alone preserves memory and thinking better than adding whole-brain radiotherapy, with no loss of survival.","status":"established","asOf":"2026-09-16","links":[{"label":"Wikipedia","url":"https://en.wikipedia.org/wiki/Radiosurgery"}],"tags":["radiation-wave1"],"related":[],"cancers":["brain-tumours","metastatic-cancer"],"sections":["radiation"],"technologies":["sbrt","imrt-igrt"],"targets":[],"drugs":[],"companies":[],"institutions":[],"pathways":[],"terms":["stereotactic-radiosurgery","wbrt","radiation-necrosis"],"trials":[],"people":[],"bottlenecks":[],"keyPapers":[],"journals":[],"notes":[],"principle":"Many narrow beams converge on a small target so the dose falls off steeply within millimetres; rigid immobilisation and image guidance keep the target within the beam.","strengths":["One to five sessions","Spares healthy brain","Treats targets surgery cannot reach"],"limitations":["Limited to small targets","Radiation necrosis in a minority","Needs precise imaging and immobilisation"],"since":1968},"route":"/technologies/radiosurgery-srs/","neighbours":{"cancer":[{"id":"brain-tumours","kind":"cancer","name":"Brain and spinal cord tumours (all types)","route":"/cancers/brain-tumours/"},{"id":"metastatic-cancer","kind":"cancer","name":"Metastatic cancer (cancer that has spread)","route":"/cancers/metastatic-cancer/"}],"section":[{"id":"radiation","kind":"section","name":"Radiation Therapy","route":"/fronts/radiation/"}],"technology":[{"id":"imrt-igrt","kind":"technology","name":"IMRT / IGRT (modern external beam)","route":"/technologies/imrt-igrt/"},{"id":"sbrt","kind":"technology","name":"SBRT / SABR (stereotactic radiotherapy)","route":"/technologies/sbrt/"}],"term":[{"id":"radiation-necrosis","kind":"term","name":"Radiation necrosis (brain)","route":"/terms/radiation-necrosis/"},{"id":"stereotactic-radiosurgery","kind":"term","name":"Stereotactic radiosurgery (SRS)","route":"/terms/stereotactic-radiosurgery/"},{"id":"wbrt","kind":"term","name":"Whole-brain radiotherapy (WBRT)","route":"/terms/wbrt/"}],"trial":[{"id":"alliance-n0574","kind":"trial","name":"Alliance N0574 (NCCTG N0574)","route":"/trials/alliance-n0574/"}]}}