Patient Information: Gamma Knife

Gamma Knife surgery is a well-established, proven technology recognized worldwide as the preferred treatment for certain types of brain tumors and other neurological diseases. The Leksell Gamma Knife® housed at the Riverside and University of Virginia Radiosurgery Center represents one of the most advanced forms of radiosurgery
currently being used.

Despite its name and scalpel-like precision, the Gamma Knife is a painless and non-invasive radiation device that delivers focused and highly accurate beams of radiation to the area of the brain requiring treatment.This safe and effective procedure offers new hope to more than 35,000 cancer and neurological patients a year as an alternative to conventional brain surgery.

The treatment consists of four basic steps:

1. Attaching a head frame used to help direct the radiation
2. CT, MRI or angiography imaging to precisely target the area to be treated
3. Individualized treatment planning based on the imaging
4. Gamma Knife treatment

How the Gamma Knife works - Click to enlargeWhat is Gamma Knife Surgery?
Gamma Knife surgery at the Riverside and University of Virginia Radiosurgery Center is a unique treatment method that delivers extremely focused radiation beams to precisely identified targets in the brain. During the one to two hour procedure, 201 individual beams of cobalt radiation converge on a single focal point. The shape and amount of the radiation is optimized to hit only the target, without damaging surrounding healthy tissue.

Why Gamma Knife Surgery?
The Leksell Gamma Knife used at the Radiosurgery Center represents a major advance in brain surgery and offers candidates for this treatment a number of important advantages over conventional, open cranial surgery:

  • Although the treatment area where the beams converge receives a very high dose of radiation each of the individual beams has low intensity so there is minimal
    risk to nearby tissue
  • The absence of an incision eliminates the risk of bleeding and infection
  • Patients experience minimal discomfort during and after the procedure
  • Hospitalization is short – Gamma Knife procedures can be performed on an outpatient basis in a single session
  • The Gamma Knife offers hope to patients who are considered untreatable or at very high risk for conventional neurosurgery

Gamma Knife - before treatmentBefore the treatment
Once Gamma Knife treatment is selected (following a complete review of your medical history and the evaluation of other treatments) your physician will inform you about the entire procedure. After arriving at the Riverside and University of Virginia Radiosurgery Center the first step is application of the head frame. Gamma Knife surgery does not require cutting or shaving of your hair.

The head frame
A key component in Gamma Knife surgery is the stereotactic (guided by three-dimensional imaging) head frame which allows the surgical team to accurately pinpoint the area being treated. This lightweight frame, which is attached to your head with four small screws, ensures that the radiation beams can be directed with precision to the target. The frame also prevents your head from moving during imaging and treatment procedures. Local anesthetic is applied where the screws are attached.

Imaging
After the head frame is in place, it is time for imaging—magnetic  resonance imaging (MRI), computed tomography (CT) or angiography (imaging the blood vessels) to be completed. This pre-operative imaging is required to determine the exact size, shape and position of the target area in the brain. During imaging, a coordinate box is placed on the head frame to provide reference points on the images for the treatment plan. After imaging, the coordinate box is removed.

Treatment planning
Gamma Knife - treatment planningAfter your images have been taken, you can rest while the surgical team develops a very precise and accurate treatment plan. No two treatment plans are alike; every patient’s plan is individually designed to address the specific medical condition. The neurosurgon, usually working together with another specialist in the team, formulates the plan in a specially designed computer and calculates how the treatment should be performed. This step usually takes a few hours.

The Gamma Knife treatment
Once your treatment plan is completed, the actual surgery begins.  You will lie down on the treatment couch and the head frame will be attached to a spherical helmet (see diagram) that focuses the beams of radiation onto the area being treated. You are awake during the procedure and will be able to communicate with your doctor or nurse through an audio and video connection. When the treatment begins, the couch will move into the dome section of the unit. The treatment is silent and totally painless. Often you will be able to listen to music during the treatment. The Radiosurgery Center team will be monitoring the procedure at all times. The treatment will last a few minutes to an hour or more, depending on the size and shape of the target area.

Gamma Knife treatment

After the treatment
When your treatment is complete, the head frame will be removed. If you had a cerebral angiogram (used for patients with arteriovenous malformations) during the imaging phase, you might have to lie quietly for several more hours. Some patients experience a mild headache or minor swelling where the head frame was attached, but most report no problems. Your doctor will tell you whether or not you’ll need to stay overnight for observation or if you can go home immediately. Either way, you should be able to return to your normal routines in another day or so.

Follow-up
The effects of your treatment will take place over time. Radiation treatments are designed to stop the growth of tumors or lesions, which means that the effect will be seen over a period of weeks or months. The medical staff at the Riverside and University of Virginia Radiosurgery Center will stay in contact with you to assess your progress, which may include follow-up MRI, CT or angiography images.

Where can I find more information?
Ask your primary care physician about Gamma Knife surgery and whether or not it is appropriate for your condition and diagnosis. In addition, you can contact patient organizations and review web sites which are relevant to your diagnosis. You can also get more information by calling the Riverside and University of Virginia
Radiosurgery Center at (757) 534-5220.


 

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