Innovations

Easier access to the brain

Stereotactic radiosurgery reduces damage to surrounding tissue

Brain surgery has long been a vexing procedure. A surgeon who got as far as opening the skull often found it impossible to go further without causing injury. Every cut, especially to access deep brain areas, risked deleting memories and emotions, the ability to walk, talk, and think.

This state-of-the-art linear accelerator-based system makes Community Hospital the only facility on the Central Coast to offer this type of treatment.

Dr. Brad Tamler, a Monterey radiation oncologist, says the accuracy of Community Hospital’s stereotactic technology is impressive.

The advent of the nuclear age has changed all that. Radiation can destroy malfunctioning tissue without a single nick from a scalpel. Delivering a large enough dose of radiation will scramble the DNA in cells. Without a good set of genetic blueprints, cells that are actively dividing will self-destruct, destroying tumors in the process.

In the 1950s, scientists figured out how to use radiation to operate on the brain. Known as stereotactic radiosurgery, or SRS, it offers a means to zap a very precise area of the brain without damaging the delicate surrounding structures. This technique is frequently used to shrink brain tumors, clot blood vessels at risk of hemorrhaging, and destroy cells such as those associated with Parkinson’s disease.

Instead of the awkward steel halo, neurosurgeons at Community Hospital will soon be able to implant three gold seeds beneath the patient’s scalp to help locate the tumor.

Monterey neurosurgeon Dr. Dragan Dimitrov admits there are pros and cons to stereotactic radiosurgery.

As with all medical procedures, there are pros and cons to SRS, says Dr. Dragan Dimitrov, a Monterey neurosurgeon. “If you can actually cut something out surgically, it’s done; you no longer have to worry about it. The risks and results are immediate. After radiosurgery, there’s the risk that the tumor won’t shrink or that a blood vessel might bleed while the radiation takes effect. The results and the risks are delayed.” SRS may be most appropriate for the elderly or those with terminal brain cancer, who might want to avoid the hospital stay and healing time associated with open surgery.

Stereotactic radiosurgery will soon be available at the Comprehensive Cancer Center at Community Hospital. This state-of-the-art linear accelerator-based system makes Community Hospital the only facility on the Central Coast to offer this type of treatment.

The trick to SRS is aiming the radiation. “The positioning has to be very, very accurate,” says Dr. Brad Tamler, a Monterey radiation oncologist. “If it’s a little bit off, it will damage healthy tissue” and might impair the brain. With Community Hospital’s new technology, the position of a brain lesion will be located within the skull by the radiation oncologist with hairsbreadth accuracy.

Improved computer technology has made SRS far more convenient, and this type of neurosurgery is now an outpatient procedure. For the first generation of SRS devices, known as gamma knives, a metal frame was bolted onto the patient’s head to serve as a reference system. Then both patient and frame would undergo an MRI and CT scan later that same day to locate the target tissue in relation to the frame. Scans in hand, the patient’s neurosurgeon and radiation oncologist would confer to determine the outlines of the target and how best to deliver the radiation.

Instead of the awkward steel halo, neurosurgeons at Community Hospital will soon be able to implant three gold seeds beneath the patient’s scalp to help locate the tumor. The MRI and CT scans that locate the target tissue can be done days in advance of the radiosurgery.

“Delivering the beams to a tumor is very much like shining a light through a magnifying glass,” Dimitrov says. “The lens focuses all the beams on one point. The machines can converge radiation beams from many directions onto a specific target. This way, tissue on the way in isn’t harmed.” Brain surgery will never be simple, but SRS will certainly help make it easier on patients and doctors alike.