What Is a Gamma Knife and What Makes It So Special?

Gamma Knife is a bit of a misnomer. It may sound like a weapon from a “Star Wars” movie, but it’s nothing of the sort.

In fact, a Gamma Knife is not a knife but rather a registered trademark for a type of radiation therapy used to treat tumors and other brain abnormalities. This noninvasive treatment involves a machine that delivers a sharply focused, high dose of radiation to its target with pinpoint accuracy. In effect, it uses beams of focused radiation to do what was once done with a scalpel (knife).

Developed in 1968, Gamma Knife can be used as an alternative to or in addition to traditional brain surgery or whole brain radiation therapy.

Surgery without a scalpel

A Gamma Knife procedure is often referred to as a “radiosurgery” but it does not involve any type of incision, making it far less invasive than traditional surgery. In most cases, the Gamma Knife procedure can be performed on an outpatient basis. It is usually a one-time therapy. Also, it does not require any hair to be shaved.

The machine used for a Gamma Knife procedure looks much like the ones used for MRIs or CT scans. It consists of a flat bed and a dome-like structure at the head of the bed. Unlike MRI, it doesn’t make a nerve-rattling noise. It operates in virtual silence. In fact, you can request music to be played while you are having your treatment.

The Gamma Knife procedure is actually a process. It begins with applying a frame or mask, after which, an imaging (such as CT or MRI) is done for planning the treatment. The actual treatment is usually completed in less than two hours, during which a patient feels no pain or discomfort.

According to Elekta, the developer of the Gamma Knife, the advanced surgical technique involves a high dose of gamma radiation delivered by nearly 200 individual beams. These beams intersect at a single spot with the accuracy of less than one-10th of a millimeter, which is about the thickness of a sheet of paper.

The precision allows the tumor or other problem to be treated with minimal radiation effect to surrounding tissues.

Shrinking or destroying the tumor or lesion is the primary goal of Gamma Knife radiosurgery. Patients typically have follow-up CT and/or MRI scans in a few months to check on treatment progress.

In addition to being used on small to medium brain tumors and abnormal blood vessel formations, the procedure can also be effective in the treatment of epilepsy, facial nerve pain and other neurological conditions.

The effects of Gamma Knife radiosurgery are generally realized over a period of time that can range from several weeks to several years, depending on the condition being treated.

Pros and side effects

Many experts consider Gamma Knife radiosurgery less risky than traditional neurosurgery because it avoids complications that some can experience with anesthesia and conventional surgery.

It is often the procedure of choice for doctors treating patients with brain tumors that can’t be reached with traditional surgery without significant risk or for patients unable to undergo more invasive treatment because of age or physical condition.

Experts say side effects are usually temporary. They include temporary headaches, a tingling sensation on the scalp, and fatigue for a few days after the procedure. Elekta reports that more than 1 million patients have been treated with Gamma Knife radiosurgery since its inception. Currently, about 80,000 patients are treated with the procedure every year.