Gamma Knife Surgery

What is gamma knife surgery?

Gamma knife surgery is a type of radiation treatment performed with the Gamma Knife®, a noninvasive neurosurgical tool. In gamma knife surgery, your doctor focuses several small, highly precise doses of radiation in the brain. This type of radiation therapy can help shrink small brain tumors or block abnormal blood vessels and nerves in the brain that cause pain or seizures. Gamma knife surgery can also help treat certain neurological disorders, such as Parkinson’s disease.

Despite its name, gamma knife surgery does not actually involve a knife or surgery. The name is derived from the knife-like precision of the radiation delivered to the target area. Gamma knife surgery is also called gamma knife radiosurgery or stereotactic radiosurgery. Gamma knife surgery may be an effective alternative to neurosurgery. Gamma knife surgery can help if you cannot tolerate neurosurgery because of your medical condition, age, or preference. It is less invasive and requires less hospitalization and recovery time compared to traditional neurosurgery. You should discuss different procedure and surgery options for your condition with your doctor to best understand which neurological treatment is right for you.

Why is gamma knife surgery performed?

Gamma knife surgery is a procedure that your doctor may recommend to treat certain diseases and conditions of the brain including:

• Acoustic neuroma, a tumor of the nerve between the brain and the ear
• Arteriovenous malformations (AVMs) and other blood vessel disorders in the brain
• Brain tumors including some types of malignant and benign tumors
• Some types of cancer of the eye
• Some types of epilepsy. A brain tumor that causes epilepsy may be treated with gamma knife surgery if anticonvulsant medications fail to control the seizures.
• Parkinson’s disease, a brain disorder that leads to uncontrollable shaking, muscle stiffness, and severe problems with coordination and balance
• Trigeminal neuralgia, a nerve disorder causing debilitating face pain

How is gamma knife surgery performed?

For gamma knife surgery, a specialized team will evaluate and care for you. The team may include a neurologist, neuroradiologist, neurosurgeon, radiation oncologist, radiation therapist, and nurses. The treatment takes place in a hospital radiology department. The entire gamma knife surgery process occurs during a single day and generally includes these steps:

1. You will dress in a patient gown and remove any jewelry, wigs, glasses or any other items that may interfere with the radiation treatment.
2. A treatment team member will start an intravenous (IV) line. You will receive fluids and a mild sedative or other medications during the procedure.
3. You will receive four small injections of local anesthetic in your head. This allows the area to become numb. Once the anesthetic takes effect, your care team will attach a head frame to your head with pins at the site of the anesthetic injections. They will not need to shave your hair to do this. Some people report a feeling of pressure when they are fitted with a head frame, but this feeling usually goes away within a few moments.
4. When your head frame is in place, the treatment team will take brain imaging scans (pictures) to precisely locate your tumor or target area. The scan might be a magnetic resonance imaging scan (MRI), a computed tomography scan (CT), a cerebral angiogram, or a combination of these. After the scan, you will wait in a separate room while your care team determines the exact treatment plan and where to apply the radiation.
5. When your care team has designed your treatment plan, you will return to the gamma knife treatment room. You will lie down on a sliding bed. Your care team will fit a treatment helmet, called a collimator helmet, over your head frame. The helmet has a special pattern of holes in it. The holes will direct radiation beams to pass through to the exact location in your brain needing treatment.
6. Your care team will slide your bed into the gamma knife machine, where you might hear a clicking sound as the helmet attaches to the machine.
7. Your care team will leave the treatment room, but they will observe you by video. You will be able to talk with them over an intercom.
8. The radiation treatment itself takes from one to four hours, depending on your personalized treatment plan. You will not feel the treatment while it is happening, and it does not produce any sounds or smells. Some people even fall asleep during treatment.
9. When the radiation treatment is complete, your care team will return to the gamma knife treatment room and slide your bed out of the treatment machine. They will remove your collimator helmet, head frame, and IV line.
10. Your care team will make sure that your vital signs, such as your blood pressure and pulse, are stable. They will give you medication for any nausea or head pain you may feel. Most people who receive gamma knife surgery go home the same day. Some patients stay in the hospital for a night for further observation.