The Gamma Knife radiosurgery system is used to treat either cancers or growths in the head or upper spine area. For cancers or growths lower down in the spine or anywhere else in the body, another focused surgery system may be used.
Before treatment, you are fitted with a “head frame.” This is a metal circle that is used to precisely position you into the machine to improve accuracy and pinpoint targeting. The frame is attached to your scalp and skull. The process is performed by the neurosurgeon, but does not require cutting or sewing.
- Using local anesthesia (like a dentist might use), four points are numbed in the skin of the scalp.
- The head frame is placed over your head and four small pins and anchors are attached. The anchors are designed to hold the head frame in place, and do go tightly through the skin into the surface of your skull.
- You are given local anesthetic and should not feel pain, rather only pressure. You also are usually given a medicine to help relax you during the fitting procedure.
- The frame will remain attached for the whole treatment procedure, usually a few hours, and then will be removed.
After the frame is attached to your head, imaging tests such as CT, MRI, or angiogram are done. The images show the exact location, size, and shape of your tumor or problem area and allow precision targeting.
After the imaging, you will be brought to a room to rest while the doctors and physics team prepare the computer plan. That may take approximately 45 minutes to an hour. Next, you will be brought to the treatment room.
Newer frameless systems for positioning the head are being evaluated.
During treatment:
- You will not need to be put to sleep. You will get medicine to help you relax. The treatment itself does not cause pain.
- You lie on a table that slides into a machine that delivers radiation.
- The head frame or face mask aligns with the machine, which has a helmet with holes to deliver small precise beams of radiation directly to the target.
- The machine may move your head slightly, so that the energy beams are delivered to the exact spots that need treatment.
- The health care providers are in another room. They can see you on cameras and hear you and talk with you on microphones.
The treatment delivery takes anywhere from 20 minutes to 2 hours. You may receive more than one treatment session. Most often, no more than 5 sessions are needed.
