Gamma Knife Radiosurgery
Gamma Knife Radiosurgery technology has revolutionized brain surgery by eliminating the need for incisions in many complex procedures. With extreme precision, Sutter Gamma Knife Radiosurgery Center physicians are able to operate on the brain with minimal risk of surgical complications. Sutter Health, with which Radiation Oncology Centers (ROC) is affiliated, is one of the few hospital systems offering this procedure.

Radiosurgery using gamma knife technology is a non-invasive, sophisticated technique in which a single, high dose of gamma radiation is used to treat inaccessible and small-to-medium-sized intracranial tumors, blood vessel abnormalities and other selected neurological disorders. A gamma knife procedure can be used to destroy a remaining or persistent lesion, tumor or arteriovenous malformation—a grouping of abnormally connected blood vessels that can cause severe headaches or seizures. The gamma knife, in combination with other forms of radiation treatments and chemotherapy, enables treatment of brain tumors that previously would have been considered untreatable.

The gamma knife is not a knife at all. Rather, it is a technologically advanced, 20-ton machine that allows surgeons to deliver 201 beams of ionizing gamma rays that precisely target the treatment area. Each individual radiation beam is weak and passes harmlessly through brain tissue on the way to the target. The beams destroy tissue only at the one point at which they all converge, under the direction of a computer with accuracy of a fraction of a millimeter. Gamma knife technology delivers enough radiation to destroy tumors or arteriovenous malformations while minimizing damage to surrounding normal tissue.

In comparison to conventional surgery with a scalpel, gamma knife technology poses less risk of damage to surrounding tissue, lets patients leave the hospital the same day as treatment in most cases, and promotes more rapid recovery.

While anesthesia and conventional surgery can pose sometimes unacceptably high risks for patients who are of advanced age or in poor medical condition, many such patients may easily tolerate gamma knife treatment. Gamma knife technology also is particularly suitable for patients whose lesions are situated in an inaccessible or functionally critical area within the brain. In addition, the treatment can be an adjunct to the care of a patient who has undergone brain surgery, interventional neuroradiology or conventional radiation therapy.

What to Expect
The procedure involves minimal pain and the entire operation requires just one to four hours, with the actual treatment performed in a single session that lasts five to 60 minutes. Because no incision is made, shaving the patient’s head is unnecessary. Patients are permitted to resume their usual lifestyle the day after treatment.

You will lie on a cushioned, motorized table that moves under a shielded dome housing the 201 gamma ray sources. The gamma-knife’s precision is achieved through a lightweight helmet that stabilizes the patient's head and serves as a reference point for beam focusing. Four screws attach the helmet to the patient’s head during the procedure. After completion of a set of imaging scans, a targeting plan for the gamma treatment is developed on a computer. That targeting plan guides the radiation beams.

Upon recommendation of their physicians, patients are referred to the Sutter Health gamma knife committee to determine whether or not gamma ray surgery is advisable. Before patients are admitted for treatment, they must undergo testing, including brain imaging or function studies, laboratory blood analysis and a physical examination. Preparation for gamma knife surgery varies, depending upon the portion of the body being treated. Ask your physician and radiation oncologist for specific information.

Possible side effects and complications vary, depending upon the procedure being performed.