Gamma Knife – Radiation Treatment at Siteman Cancer Center
If you have a brain tumor or neurological disorder located in an especially hard-to-reach area, you may be a good candidate for Gamma Knife radiosurgery. Gamma Knife isn’t actually a knife – instead, it’s a machine that delivers a powerful dose of radiation to a targeted point in the brain. Attacking diseased tissues with extreme precision, this treatment leaves healthy tissues untouched.
At Siteman, we use the Gamma Knife Icon, the newest and most sophisticated machine available. The Icon is unique because it allows for both framed and frameless treatments. This means that patients can sometimes wear a mesh mask instead of the traditional titanium frame that is used to keep the head still during the procedure.
Siteman houses the only Gamma Knife in eastern Missouri, and our patients come to us from all over the region. Because the procedure only requires one to five treatment sessions at most, it is convenient for many of our traveling patients.
Our facility, operated as Gamma Knife of St. Louis, is staffed in partnership with Barnes-Jewish Hospital, the Washington University School of Medicine in St. Louis, and HealthSouth, now Encompass Health. More than 5,000 patients have received treatment through our program since it opened in 1998.
What is Gamma Knife Surgery?
Though no incisions are involved, Gamma Knife is considered a form of surgery because it can eliminate tumors with the accuracy of a surgical procedure. Patients reap the benefits of surgery without many of the risks, such as infections, bleeding, and complications arising from anesthesia. Local anesthetic is often the only painkiller required, just as you might receive at the dentist’s office.
Gamma Knife delivers a higher dose of radiation than whole-brain radiotherapy, but the dose is broken down into 192 separate beams emitted by the cobalt-60 radiation sources. Each beam is too weak to significantly injure healthy tissue by itself, and passes safely through the brain until it reaches the tumor. All of the beams come together at the tumor or treatment area, producing an intense dose of radiation contained within that specific site. The radiation is directed to the tumor like a magnifying glass reflecting the sun. Your doctors will use advanced imaging technology to make sure the radiation beams are concentrated on the right spot.
What conditions does Gamma Knife treat?
The procedure treats a variety of malignant and non-malignant brain lesions, specifically those that are smaller in size. Some of these include:
- Metastatic brain tumors
- Acoustic neuromas or schwannomas
- Pituitary adenomas
- Pineal tumors
- Trigeminal neuralgia
- Pediatric tumors
- Arterial venous malformations
- Essential tremor
- Other conditions
Our team is especially skilled at treating metastatic tumors in the brain. Individuals with metastatic tumors make up the largest percentage of our patients.
What happens during Gamma Knife treatment?
During treatment, the patient’s head is kept perfectly still while radiation is beamed to the tumor. Doctors use either a titanium frame or a mesh mask to hold the patient’s head in place. Each device requires a different preparation process.
The decision to use a frame or a mask often depends on the size or location of the tumor. Larger tumors might require too much radiation to treat safely in one session. The mask – which doesn’t have to be physically attached to the patient’s head – better allows doctors to “fractionate” treatments, or to space them out over a period of days.
However, some tumors are not in locations that could best be served by the mask. In these cases, doctors will recommend the frame.
Sometimes, patients themselves have the opportunity to decide whether they would prefer the frame or the mask.
Advantages of Gamma Knife
Gamma Knife is safer in the short term than traditional neurosurgery, with a much shorter recovery period and a reduced risk of complications. These are some of the advantages:
- There are no incisions, which means you are unlikely to get an infection.
- The process is completed in one to five days and does not require a lengthy stay in the hospital. This keeps costs down.
- The recovery period is very quick. Patients can return to their ordinary routines the following day if they wish.
- No healthy brain tissues are touched or harmed.
Does Gamma Knife cause any side effects?
There are a number of side effects associated with Gamma Knife treatment. Most Gamma Knife side effects are not severe and will go away on their own. Patients may notice the following shortly after the procedure:
- Nausea and/or vomiting
- Redness or irritation where the frame was attached
Contact your doctor or go to the emergency department if you notice or experience any of the following:
- Inflammation or redness at the frame placement sites
- A fever of 101 degrees F or higher
- Changes in vision
- A sudden inability to speak
Because it can take several weeks or months for the radiation to take full effect in your brain, some side effects may develop over time. These include:
- Brain swelling in the area of the tumor
Brain swelling sounds alarming, but in these cases, the swelling is not as dangerous or urgent because it develops more gradually. Medications such as corticosteroids can reduce or prevent swelling.
Be sure to speak with your doctor about any concerns you may have. Our nursing staff is also extremely knowledgeable and welcomes questions from patients and family members. We want you to be able to participate fully in your care and to know how best to handle your recovery at home.