{"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":"2026-09-17","links":[{"label":"Wikipedia","url":"https://en.wikipedia.org/wiki/Radiosurgery"}],"tags":["radiation-wave1"],"related":["gamma-knife","cyberknife","zap-x"],"cancers":["brain-tumours","metastatic-cancer","secondary-brain-tumours","meningioma","vestibular-schwannoma","spinal-cord-tumours"],"sections":["radiation"],"technologies":["sbrt","imrt-igrt"],"targets":[],"drugs":[],"companies":["elekta","accuray","zap-surgical-systems","brainlab","varian"],"institutions":[],"pathways":[],"terms":["stereotactic-radiosurgery","wbrt","radiation-necrosis"],"trials":["alliance-n0574"],"people":[],"bottlenecks":[],"keyPapers":[],"journals":[],"dependsOn":[],"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":{"technology":[{"id":"bnct-accelerator-systems","kind":"technology","name":"Accelerator-based BNCT systems (NeuCure, nuBeam, NeuPex)","route":"/technologies/bnct-accelerator-systems/"},{"id":"cyberknife","kind":"technology","name":"CyberKnife robotic radiosurgery","route":"/technologies/cyberknife/"},{"id":"gamma-knife","kind":"technology","name":"Gamma Knife","route":"/technologies/gamma-knife/"},{"id":"imrt-igrt","kind":"technology","name":"IMRT / IGRT (modern external beam)","route":"/technologies/imrt-igrt/"},{"id":"litt-systems","kind":"technology","name":"Laser interstitial thermal therapy systems (NeuroBlate, 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cancer","route":"/cancers/extensive-stage-sclc/"},{"id":"gonadotroph-pitnet","kind":"cancer","name":"Gonadotroph pituitary neuroendocrine tumour (non-functioning adenoma)","route":"/cancers/gonadotroph-pitnet/"},{"id":"her2-mutant-nsclc","kind":"cancer","name":"HER2-mutant non-small-cell lung cancer","route":"/cancers/her2-mutant-nsclc/"},{"id":"her2-positive-breast-brain-metastases","kind":"cancer","name":"HER2-positive breast cancer with brain metastases","route":"/cancers/her2-positive-breast-brain-metastases/"},{"id":"lactotroph-pitnet","kind":"cancer","name":"Lactotroph pituitary neuroendocrine tumour (prolactinoma)","route":"/cancers/lactotroph-pitnet/"},{"id":"lung-cancer","kind":"cancer","name":"Lung cancer (all types)","route":"/cancers/lung-cancer/"},{"id":"meningioma","kind":"cancer","name":"Meningioma","route":"/cancers/meningioma/"},{"id":"metastatic-cancer","kind":"cancer","name":"Metastatic cancer (cancer that has spread)","route":"/cancers/metastatic-cancer/"},{"id":"tnbc-metastatic","kind":"cancer","name":"Metastatic triple-negative breast cancer","route":"/cancers/tnbc-metastatic/"},{"id":"ret-fusion-nsclc","kind":"cancer","name":"RET fusion-positive non-small-cell lung cancer","route":"/cancers/ret-fusion-nsclc/"},{"id":"ros1-positive-nsclc","kind":"cancer","name":"ROS1-positive non-small-cell lung cancer","route":"/cancers/ros1-positive-nsclc/"},{"id":"somatotroph-pitnet","kind":"cancer","name":"Somatotroph pituitary neuroendocrine tumour (acromegaly)","route":"/cancers/somatotroph-pitnet/"},{"id":"spinal-cord-tumours","kind":"cancer","name":"Spinal cord tumours (intramedullary and intradural)","route":"/cancers/spinal-cord-tumours/"},{"id":"thyrotroph-pitnet","kind":"cancer","name":"Thyrotroph pituitary neuroendocrine tumour (TSH-secreting)","route":"/cancers/thyrotroph-pitnet/"},{"id":"vestibular-schwannoma","kind":"cancer","name":"Vestibular schwannoma (acoustic neuroma)","route":"/cancers/vestibular-schwannoma/"}],"section":[{"id":"radiation","kind":"section","name":"Radiation Therapy","route":"/fronts/radiation/"}],"company":[{"id":"accuray","kind":"company","name":"Accuray","route":"/companies/accuray/"},{"id":"brainlab","kind":"company","name":"Brainlab","route":"/companies/brainlab/"},{"id":"elekta","kind":"company","name":"Elekta","route":"/companies/elekta/"},{"id":"nordion","kind":"company","name":"Nordion (Sotera Health)","route":"/companies/nordion/"},{"id":"varian","kind":"company","name":"Varian (Siemens Healthineers)","route":"/companies/varian/"},{"id":"zap-surgical-systems","kind":"company","name":"ZAP Surgical Systems","route":"/companies/zap-surgical-systems/"}],"term":[{"id":"lung-palliation-breathlessness-effusion-obstruction","kind":"term","name":"Palliation in lung cancer: breathlessness, pleural effusion, blocked airway, bone and 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