Patients with certain types of brain tumors and disorders no longer need to "go under the knife" or endure physically draining radiation therapy to find relief. With Gamma Knife technology, doctors are able to deliver over 200 beams of radiation with scalpel-like precision directly to tumors and lesions.
Although many people have never heard of Gamma Knife, the procedure has been around for a long time. The Food and Drug Administration approved it nearly 30 years ago, and University of Maryland doctors have been administering Gamma Knife treatments for over a decade. In fact, more than 2,500 patients have come to the University of Maryland Medical Center for Gamma Knife surgery.
Unlike traditional surgery, Gamma Knife procedures don't actually involve the use of a "knife" or scalpel. In fact, no incisions are made at all. The skull never has to be opened up.
The following conditions are among those that can be treated with a Gamma Knife.
Gamma Knife also differs from conventional radiation therapy. Because patients are injected with such low doses of radiation, they don't experience the side effects associated with traditional radiation therapy. In fact, several "shots" of therapy can be given during the same session, and treatment sessions can be repeated every few weeks if necessary.
Gamma Knife can be used to treat a variety of conditions. It is most often used on tumors, either cancerous or benign.
Benign tumors such as meningiomas and acoustic neuromas, and malignant tumors that have metastasized can all be effectively treated. Doctors typically use the Gamma Knife to treat tumors that are smaller than four centimeters in size.
Gamma Knife is able to stop tumors from growing in 90 to 95 percent of all cases. It also causes tumors to shrink in the majority of cases. Shrinkage can take anywhere from a week to a year, depending how rapidly the tumors' cells try to divide.
Gamma Knife can also be used in treating disorders such as arteriovenous malformations (AVM), Parkinson's disease and trigeminal neuralgia. Patients with AVM have abnormal tangles of blood vessels in their brains that can bleed, causing seizures and hemorrhagic stroke. Trigeminal neuralgia is a condition that causes pain around the cranial nerves near the base of the brain. This pain tends to radiate out to pressure points in the face, and can be nearly unbearable for some patients.
When patients first come to the University of Maryland Medical Center for treatment, they must meet with the Gamma Knife medical team. The team is made up of three dedicated neurosurgeons and a radiation oncologist. The team then collaborates and decides on the best way to treat the patient's condition.
On the day of the surgery, patients are fitted with a clear, plastic frame. This frame sits over their heads and helps team members to measure the distance the radiation beams must travel. The team then uses three-dimensional, computerized technology to figure out exactly where to administer the radiation.
Once this has been determined, patients are placed into the Gamma Knife apparatus. The Gamma Knife is a metal, helmet-like device that emits the radiation beams.
According to the medical team, the entire procedure, from the time the patient first arrives at the Gamma Knife Center to the completion of the treatments, only takes about four or five hours. Patients typically spend one night in the hospital and then go home.
Radiation is invisible energy that slices through tumor cells and vessels. Radiation therapy uses high-energy light beams (X-rays or gamma rays) or changed particles (electron beams or proton beams) to damage the DNA of tumor cells or lesions.
If enough damage is done to the chromosome of a cell, it will die spontaneously or it will die the next time it tries to divide into two cells.
Tumors are poorly vascularized tissues that are deprived of oxygen. Radiation, however, requires a lot of oxygen. Radiation therapy controls tumors by splitting the oxygen molecules it finds in and around tumors into harmful oxygen radicals that destroy tumor cells.
Gamma Knife works in AVM patients by damaging the abnormal tangle of blood vessels in their brains, and forming scar tissue. Once scarred vessel walls thicken, they clog up and become sealed off. Blood can no longer leak through them, causing seizures or stroke.