Why it's done

Gamma Knife radiosurgery is often a safer alternative to standard brain surgery (neurosurgery), which requires incisions in the scalp, an opening in the skull and membranes surrounding the brain, and dissection into brain tissue. This type of radiation treatment is usually performed when:

• A tumor or other abnormality in the brain is too hard to reach with standard neurosurgery
• A person isn't healthy enough to undergo standard surgery
• A person prefers a less invasive treatment

In some cases, Gamma Knife radiosurgery may have a lower risk of side effects compared with other types of radiation therapy and it can all be done in one day compared with up to 30 treatments with conventional radiation therapy.

Gamma Knife radiosurgery is most commonly used to treat the following conditions:

• Brain tumor. Radiosurgery is useful in the management of small noncancerous (benign) and cancerous (malignant) brain tumors.

  Radiosurgery damages the genetic material (DNA) in the tumor cells. The cells lose their ability to reproduce and may die, and the tumor may gradually shrink.

• Arteriovenous malformation (AVM). AVMs are abnormal tangles of arteries and veins in your brain. In an AVM, blood flows from your arteries to veins, bypassing smaller blood vessels (capillaries). AVMs, if left untreated, may "steal" the normal flow of blood from the brain, causing a stroke, or lead to bleeding in the brain.

  Radiosurgery destroys the AVM and causes the blood vessels to close off over time.

• Trigeminal neuralgia. Trigeminal neuralgia is a 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 disabling facial pain that feels like an electric shock.

  After treatment, many people will experience pain relief within a few days to a few months.

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

  When the tumor puts pressure on the nerve, you 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.

  Radiosurgery may stop the growth of an acoustic neuroma.

• 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 regulates hormones in your body that control various functions, such as your stress response, metabolism and sexual function.

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