What is Gamma Knife® radiosurgery?

Gamma Knife® radiosurgery, also known as stereotactic radiosurgery, is a form of radiation used to treat brain disorders. Despite its name, this procedure does not involve a surgical incision into the brain. Also, the “blades” of the gamma “knife” are actually beams of highly focused gamma ray radiation. Up to 192 beams of radiation are precisely focused on the lesion/targeted area in the brain. Because the beams are so highly focused, there is little damage to the surrounding healthy tissue.

Compared with traditional surgery, Gamma Knife® radiosurgery does not require general anesthesia. It also avoids other risks and complications of surgery (such as bleeding and infection). There is also little or no post-treatment discomfort or pain. Gamma Knife® radiosurgery is usually performed as an outpatient procedure. Sometimes, however, patients may stay in the hospital overnight. Most patients can resume their usual activities in a day or two. Physical therapy or other rehabilitation is not needed.

What conditions does Gamma Knife® radiosurgery treat?

Gamma Knife® radiosurgery can treat several brain disorders, including:

  • Acoustic neuroma – a non-cancerous tumor that develops around the balance and hearing nerves that connect the inner ear with the brain
  • Arteriovenous malformations (AVMs) – abnormal, snarled tangles of blood vessels
  • Brain tumors (both cancer and non-cancer) – including pituitary adenomas, pinealomas, craniopharyngiomas, meningiomas, chordomas, chondrosarcomas, metastases, and glial tumors
  • Tremors due to essential tremor or Parkinson’s disease
  • Trigeminal neuralgia – an ongoing condition that affects a certain nerve in the face, causing extreme pain
  • Some types of epilepsy

The Gamma Knife® can be helpful in patients with brain lesions that cannot be reached by traditional surgery techniques and in those who are unable to undergo surgery due to their condition or age. It can also be combined with traditional surgery to prevent tumor regrowth. Because Gamma Knife® results occur slowly over time, this is not a procedure for conditions that need immediate treatment.

Last reviewed by a Cleveland Clinic medical professional on 07/14/2017.


  • Expert knowledge and experience of healthcare providers at Cleveland Clinic Gamma Knife Center.
  • American College of Radiology and the Radiologic Society of North America. Gamma Knife. Accessed 5/22/2017.

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