LEXINGTON, Ky. (March 30, 2009) - If you happen to be walking or driving past the UK Albert B. Chandler Hospital today, you might notice something out of the ordinary on Rose Street: a giant crane hoisting a 6-foot, 22-ton metal sphere through a skylight into the lower level of the Markey Cancer Center..
That massive orb is part of a $4.5 million upgrade to the medical center's Gamma Knife facility, which enables doctors to treat brain tumors and other neurological disorders without surgery. The Gamma Knife uses nearly 200 separate, precisely focused beams of electromagnetic energy, called gamma rays, to target and kill diseased cells while sparing surrounding healthy tissue.
Dr. Marcus Randall, chief of UK's Department of Radiation Medicine and director of its new Brain and Body Radiosurgery Program, awaits the lowering of the big ball today with all the eagerness and anticipation of a Times Square crowd on New Year's Eve.
"You just have to be amazed by what a remarkable feat of engineering this is," Randall said. Although he has been involved in two previous Gamma Knife installations at other institutions, Randall says he'll still be watching the action today. "This kind of thing doesn't get old," he said.
The giant sphere being installed today will position and shield the sources for the gamma rays: 192 rods of cobalt-60, a lab-engineered radioactive isotope of a common mineral element. Each rod will be contained within its own precision-machined housing on the inside. The rods gradually become depleted and need to be replaced about once every five years, at a cost of around $1 million.
UK's old Gamma Knife was due for a recharge this year. After weighing all of the options, the hospital decided that upgrading to the new Gamma Knife Perfexion system would be the most cost-effective choice in the long run, Randall said.
One key advantage of the new system is that it will streamline the process, cutting treatment times by about 70 percent. This reduces stresses to the patient, Randall says, and the improved efficiency potentially could increase the number of patients that UK can treat.
Earlier Gamma Knife models used a series of 300-pound "helmets" with holes of different fixed sizes, called apertures, to narrow and focus the gamma beams onto targets as small as 4mm in diameter inside the patient's head. Treatment often involved moving the patient in and out of the machine one or more times to change these helmets.
The new system, which will be used to treat patients starting May 4, uses a helmet with variable-width apertures, which can be adjusted without needing to move the patient at all.
Treatment with the Gamma Knife, called radiosurgery, is used to fight brain tumors by stopping their growth, sometimes actually shrinking them. This alleviates symptoms and can even extend life expectancy in some patients, Randall said.
The procedure can effectively cure certain types of benign intracranial tumors, such as acoustic neuroma (a noncancerous growth on the nerves leading to the ear), which can cause a loss of hearing and balance. Radiosurgery has also been shown to be effective in about 80 percent of patients with trigeminal neuralgia, a chronic condition that causes debilitating facial pain.
"It's not a miracle cure," Randall said. "Patients still need to meet specific criteria with regard to tumor type, size and location, among other factors. But for the right patient, the Gamma Knife can produce truly remarkable results in just one or two treatments, without hospitalization and without the risks of many of the complications possible with surgery."
Radiosurgery does carry its own risks. Fortunately, Randall says, serious complications are extremely rare, and the overall risk profile compares favorably to that of traditional "open" surgery.
Treatment with the Gamma Knife also costs less. It's still quite expensive, but without the associated costs of hospitalization, the total bill ends up being around half as much or less compared to surgical treatment, Randall said.
UK installed the seventh Gamma Knife in the United States in 1991. Today there are more than 100 Gamma Knifes nationwide, treating more than 35,000 patients each year. UK still has the only Gamma Knife in Kentucky, treating over 200 patients annually.
Gamma Knife is a registered trademark, and Perfexion is a trademark of Elekta Group, manufacturer of the Gamma Knife system.