Stereotactic Radiation Therapy

Stereotactic radiation therapy is a specialized form of external radiation treatment where very high doses of very precise radiation are directed at small targets. The treatment is delivered under highly controlled conditions with precise patient localization. Because of the high-dose treatment, the number of individual treatments is fewer than typical external beam radiotherapy (typically between one and five individual treatments). However, these treatments may take 30-60 minutes to deliver, in part due to the advanced imaging and immobilization required.

The use of these high-dose stereotactic treatments is growing. Typical areas that may be treated with these techniques include small tumors in the brain, lung, liver, or spine. These treatments are often called Stereotactic Body Radiotherapy (SBRT). The term Stereotactic Radiosurgery (SRS) typically refers to a single high-dose external radiation treatment directed at small brain tumors.

Gamma Knife

The Gamma Knife is a specialized radiosurgery device that delivers a high dose of external radiation using multiple pinpoint beams to a small target within the brain. It is a way to treat brain tumors and certain other brain diseases (arteriovenous malformations, trigeminal neuralgia, vestibular schwannomas, certain functional disorders, and others) without a scalpel or incision. Gamma Knife treatment is a one-day outpatient procedure that is virtually painless. The patient’s head does not need to be shaved for the procedure.

The Gamma Knife procedure is a team effort involving the radiation oncologist, neurosurgeon, and medical radiation physicist. On the day of treatment, the neurosurgeon attaches the head frame to the patient. The head frame remains on the patient for the entire procedure; it provides a reference platform for the location of the patient’s anatomy and tumor during imaging. It also serves to immobilize the patient during treatment.

After the frame is in place, a series of CT and/or MRI scans are taken. Thereafter, the patient simply rests while the imaging data is transferred to a specialized computer system. In many cases the patient can read, watch television, or even eat while planning takes place.

The computer system determines the precise target position, dosage, and configuration of pinpoint radiation beams. This positioning optimizes the dose to the tumor while minimizing the exposure of healthy tissue. Once the treatment plan is approved by the radiation oncologist, the treatment is delivered.

The Gamma Knife Center is led by Dr. Paul Sperduto.