It’s called a gamma knife, but there’s not a blade on it. This medical device, which involves no cutting at all, delivers radiation to a spinal cord or brain tumor with the intent of destroying the tumor cells.
Gamma Knife Surgery: What It Is and How It's Done
Gamma knife surgery is a type of stereotactic radiosurgery, which is a form of radiation therapy that aims low-dose radiation beams, coming from all sides of the head, directly at the brain tumor. This results in a high dose of radiation at the center of the tumor, where the many radiation beams meet.
Gamma knife surgery uses three-dimensional imaging techniques to accurately target the tumor before the radiation is given. After taking MRIs (magnetic resonance imaging scans) and CT (computed tomography) scans, your treatment team will plan your treatment with gamma knife surgery.
After a plan is in place and before you receive the treatment, doctors will put a frame around your head to hold it still. To place the frame, your medical team will numb certain areas of your scalp and use tiny screws or pins to position the head frame in place. Wearing this frame, your head is then placed inside a clear helmet which has small holes through which the radiation beams are directed at the brain tumor.
Gamma Knife Surgery: Is It for You?
Gamma knife surgery is particularly effective for people whose tumors are:
- Three centimeters or less in diameter
- Either benign (non-cancerous) or malignant (cancerous)
If you have a spinal cord or brain tumor, talk with your doctor about whether gamma knife surgery is an option for you. Before your medical team makes a decision, team members will carefully review the results of CT and MRI scans, positron emission tomography (PET) scans, cerebral angiography, and other tests.
Benefits of Gamma Knife Surgery
There are many benefits of gamma knife surgery, including:
- It is extremely accurate. Because the gamma knife so precisely targets the brain tumor, areas outside of the tumor are not exposed to much radiation, which can reduce the risk of side effects and damage to nerves and blood vessels in surrounding areas of the brain.
- No incision is required. Since gamma knife surgery is actually not a surgery but a form of radiation therapy, no incision is made and general anesthesia is not required. Therefore, the risks associated with skull incisions and general anesthesia can be avoided.
- Only one treatment is needed. It usually takes just one 10-minute to 70-minute procedure to deliver radiation with the gamma knife.
- It works. There is evidence that treatment of certain malignant brain tumors with gamma knife surgery can increase a patients' lifespan.
Risks of Gamma Knife Surgery
Potential risks and side effects of gamma knife surgery include:
- Tenderness where the screws or pins were placed
- Nausea and vomiting
- Hair loss where the radiation was directed
- Damage to surrounding tissues in the brain, caused by swelling. These effects may be delayed, and may cause symptoms mimicking a stroke or a recurrence of tumor
Gamma Knife Surgery: Preparation
To prepare for gamma knife surgery:
- Stop taking certain medications before your procedure, as directed by your medical team.
- Take all medications prescribed by your medical team, which may include steroids and anti-seizure drugs.
- Follow your medical team's instructions regarding what to eat and drink in the days leading up to your procedure.
- Wash your hair the night before your procedure, if your doctor recommends it.
- Arrange to have someone drive you home after your procedure.
In most cases, you will be able to go home the same day of your gamma knife surgery.. Follow your doctor's instructions regarding how to care for yourself after the procedure. You will most likely be able to resume your normal activities within a couple of days. Contact your medical team if you have any questions, and attend follow-up appointments as directed.