Rays of hope

Gamma Knife Center ushers in new era of brain surgery

Stephen Haines, head of the Department of Neurosurgery, and the Gamma Knife.

By Mary Hoff

Published on August 12, 2005

How do you fix disorders deep within the brain? Reaching and destroying tumors or other malfunctioning tissue without harming healthy cells has been a challenge for neurosurgeons for generations.

With the installation of Gamma Knife technology and the opening of the Gamma Knife Center at the University of Minnesota Medical Center, Fairview, the Twin Cities medical community has a dramatically improved ability to treat selected tissues with unprecedented precision.

The Gamma Knife is not an actual knife, but a device for focusing 201 separate beams of high-energy radiation on a single spot. As the rays converge from all directions, their energy adds up, creating a force powerful and precise enough to destroy a point the size of a peppercorn. "The advantage to the Gamma Knife is you can deliver a large amount of radiation in a single dose with minimal damage to normal tissues around the lesion," says Stephen Haines, head of the Department of Neurosurgery. "It's an enhancement to our brain tumor management program." With the installation of the Gamma Knife, "the department is well on its way to reestablishing a leadership role in cutting-edge neurosurgery," Haines says.

The Gamma Knife is not an actual knife, but a device for focusing 201 separate beams of high-energy radiation on a single spot. As the rays converge from all directions, their energy adds up, creating a force powerful and precise enough to destroy a point the size of a peppercorn.

Before the Gamma Knife became available at the University of Minnesota Medical Center, this type of treatment, known as stereotactic radiosurgery, was performed using a linear accelerator. The linear accelerator radiosurgery system is still used when the radiation dose needs to be divided over several days. For most purposes, however, the Gamma Knife is used for one-time treatment. The length of treatment depends on the size and shape of the tumor, but averages about a half-hour, and most patients go home the same day.

The Gamma Knife is primarily used to stop the growth of cancer cells. It also can be used for trigeminal neuralgia, which produces excruciating facial pain, and for eliminating malformed brain blood vessels. Though not a replacement for conventional brain surgery, the technology provides a valuable option for certain circumstances.

"It's particularly ideal for those who can't tolerate surgery or whose tumors aren't in a location that can be operated on," says radiation oncologist Paul Sperduto, a physician with Minneapolis Radiation Oncology who co-directs the Gamma Knife Center with University of Minnesota neurosurgeon Walter Hall and radiation oncologist James Orner. "It's clearly a step forward."

Kenneth Rush is one of more than a dozen patients treated at the Gamma Knife Center in its first month of operation. Rush had conventional surgery two years ago on a pituitary tumor, but the mass could not be completely removed because of its proximity to his optic nerve. When the tumor began to regrow, the Gamma Knife allowed doctors to knock it back without damaging his vision or other brain function.

"I'm thankful we have technology like this and the people who can put it to use," Rush says. University of Minnesota Medical Center, Fairview, and University of Minnesota Physicians Neurosurgery and Therapeutic Radiology Services partnered with Minneapolis Radiation Oncology to bring the Gamma Knife to the Twin Cities. By sharing the technology with each other and with other care providers, collaborators are maximizing their ability to provide patients with top-notch technology in a cost-effective way. "It's a statement of the will and desire of the University the University of Minnesota Medical Center to be a community resource and to work with the physician community," Haines says.

In addition to providing the best available stereotactic radiosurgery, the Gamma Knife offers opportunities to explore ways to further improve care. Some researchers are conducting studies to find the best combination of targeted radiation, whole-brain radiation, and chemotherapy for treating tumors. Others plan to explore potential applications to managing seizure disorders, Parkinson's disease, and other ailments.

From Pictures of Health, summer 2005, a publication of the Academic Health Center.