Pittsburgh, January 28, 2002 -- The recently introduced gamma knife with robotic automatic patient positioning system (APS) permits greater accuracy in radiation-dose planning during brain surgery, provides faster treatment and more flexibility in dose delivery, according to a study in the February 2002 issue of Neurosurgery.

The gamma knife procedure, commonly referred to as bloodless brain surgery, uses irradiation to treat arteriovenous malformations, acoustic neuromas, meningiomas, brain metastases, glial neoplasms, malignant skull base tumors, trigeminal neuralgia and epilepsy.

The new model gamma knife, first used at the University of Pittsburgh Medical Center (UPMC) in 2001, permits precise robotic controlled movement of the patient's head and stereotactic frame during the procedure. This study reports on the treatment of the first 134 patients using the new APS technology.

"We found the accuracy of the robotic system allows us to use greater numbers of smaller and narrower beams of radiation. This results in steeper falloffs of the radiation outside the target area, resulting in a more conformal dose plan and a potentially better outcome for the patient," said Douglas S. Kondziolka, MD, professor of neurological surgery and radiation oncology in the University of Pittsburgh School of Medicine's department of neurological surgery and principal investigator in the study. Dr. Kondziolka is co-director with L. Dade Lunsford, MD, the Lars Leksell professor and chairman, department of neurological surgery, of UPMC's Center for Image-Guided Neurosurgery.

The study also found that because of the APS system, multiple uses of different sizes of collimator helmets used to focus the radiation were not needed, saving time and making the procedure more comfortable for patients.

The gamma knife delivers a single high dose of irradiation at targets of just several millimeters up to 3 centimeters in diameter. Because the beam focuses precisely on the offending tissues, effects on surrounding brain tissue are minimized.

Surgery using the gamma knife is safer than many existing procedures because patients need not undergo risky, open-skull procedures and adult patients do not require general anesthesia. It causes few side effects, and patients usually leave the hospital within 24 hours.

In 1987, the University of Pittsburgh Medical Center was the first in the United States to treat patients with the first generation of gamma knife. Since then, the department of neurological surgery has performed gamma knife procedures on almost 5,000 patients, the largest clinical experience in the United States.