Why it's done

Around 50 years ago, stereotactic radiosurgery was pioneered as a less invasive and safer alternative to standard brain surgery (neurosurgery), which requires incisions in the skin, skull, and membranes surrounding the brain and brain tissue.

Since then, the use of stereotactic radiosurgery has expanded widely to treat a variety of neurological and other conditions, including:

• Brain tumor. Stereotactic radiosurgery, such as Gamma Knife, is often used to treat noncancerous (benign) and cancerous (malignant) brain tumors, including meningioma, paraganglioma, hemangioblastoma and craniopharyngioma.

  SRSmay also be used to treat cancers that have spread to the brain from other parts of the body (brain metastases).

• Arteriovenous malformation (AVM). AVMs are abnormal tangles of arteries and veins in your brain. In an AVM, blood flows directly from your arteries to veins, bypassing smaller blood vessels (capillaries). AVMs may disrupt the normal flow of blood and lead to bleeding (hemorrhage) or stroke.

  Stereotactic radiosurgery destroys the AVM and causes the affected blood vessels to close off over time.

• Trigeminal neuralgia. Trigeminal neuralgia is a chronic pain disorder of one or both of the trigeminal nerves, which relay sensory information between your brain and areas of your forehead, cheek and lower jaw. This nerve disorder causes extreme facial pain that feels like an electric shock.

  Stereotactic radiosurgery treatment for trigeminal neuralgia targets the nerve root to disrupt these pain signals.

• Acoustic neuroma. An acoustic neuroma (vestibular schwannoma), is a noncancerous tumor that develops along the main balance and hearing nerve leading from your inner ear to your brain.

  When the tumor puts pressure on the nerve, a person can experience hearing loss, dizziness, loss of balance and ringing in the ear (tinnitus). As the tumor grows, it can also put pressure on the nerves affecting sensations and muscle movement in the face.

  Stereotactic radiosurgery may stop the growth or minimize the size of an acoustic neuroma with little risk of permanent nerve damage.

• Pituitary tumors. Tumors of the bean-sized gland at the base of the brain (pituitary gland) can cause a variety of problems. The pituitary gland controls hormones in your body that control various functions, such as your stress response, metabolism, growth and sexual function.

  Radiosurgery can be used to shrink the tumor and lessen the disruption of pituitary hormone regulation.

• Tremors. Stereotactic radiosurgery may be used to treat tremors associated with functional neurological disorders such as Parkinson's disease and essential tremor.
• Other cancers. SRS may be used to treat cancers of the liver, lung and spine.

Researchers are also exploring the use of stereotactic radiosurgery to treat other conditions, including melanoma of the eye, breast cancer, lung cancer, prostate cancer, epilepsy and psychological disorders such as obsessive-compulsive disorder.