"This is the first clinical trial in the United States of this promising treatment for epilepsy," says Paul DesRosiers, M.D., assistant professor of radiation oncology and the principal investigator of the IU School of Medicine trial. "As many as 10 patients will be treated at IU in this trial which is designed to determine the most effective radiation dose for eliminating the seizure focus in the brain."
Currently, the only approved treatments involve medication or invasive surgery. This new radiosurgery protocol uses the Gamma Knife to focus 201 beams of gamma radiation on the precise location of the brain responsible for the seizures.
When the beams converge, the targeted area of the brain receives a full-treatment dose of radiation. Gamma Knife radiosurgery spares healthy areas of the brain from high-dose exposure to gamma radiation.
Patients over the age of 18 with a specific form of temporal lobe epilepsy, who would otherwise be candidates for the traditional surgery, are eligible to participate in this clinical trial. It is estimated that up to 1 percent of the U.S. population has epilepsy and that 20 percent of those patients have the type of epilepsy that may benefit from surgery. The surgery, for patients with seizures stemming from one temporal lobe of the brain, is up to 95 percent effective.
"The IU Comprehensive Epilepsy Program is the only one in Indiana dealing with these extreme cases," says Vincenta Salanova, M.D., associate professor of neurology and co-director of the program. "More than 500 patients have been evaluated in the clinic and, of those, 300 have qualified for surgery. As many as 90 percent of these patients became seizure free or had rare seizures, with significant improvement in their quality of life. Preliminary data indicate that the Gamma Knife radiosurgery also may be effective for select patients and will offer them another treatment option."
Gamma Knife radiosurgery eliminates many of the risks inherent with traditional surgery because it is non-invasive. The radiation is diffused through a 300-pound collimator helmet, which resembles a large version of the kitchen colander. The patient's head is placed inside the helmet and held fast at four points to the skull. Each of the "drain holes" is actually an aperture that creates beams of varying strength and diameter allowing precise delineation of the area to be treated. When the individual beams converge, that area receives the full treatment dose of gamma radiation. Treatment time is much less than that of traditional surgery and the recovery period usually involves only one over-night hospital stay. Faculty members from the IU Departments of Neurology, Neurosurgery, Neuroradiology and Radiation Oncology are involved in the clinical trial.
Treatments will be done in the Indiana Lions Gamma Knife Center at the Indiana Cancer Pavilion. The center is directed by Robert Timmerman, M.D., assistant professor of radiation oncology, and Thomas Witt, M.D., associate professor of neurosurgery.
IU School of Medicine was the first in the state to use Gamma Knife radiosurgery technology. The first patient in Indiana was treated in September 1997 and since then more than 500 patients with benign and malignant brain tumors, vascular malformations or facial pain, such as trigeminal neuralgia, have been treated with this sophisticated technology.
Recent advances in neuroradiology have made it possible to more precisely evaluate the function of different regions of the brain leading to advanced treatments such as radiosurgery for epilepsy.
For more information on the IU Gamma Knife program, see www.iupui.edu/~neurosur/GammaKnife.html or www.clarian.org/clinical/gammaknife/index.jhtml?print=true