Swiftly, precisely, silently, millimeter-wide metal leaflets slide back and forth inside a radiation machine, dispersing powerful beams with a colander-like effect. Each tiny opening appears just long enough to let high-energy radiation fall on its intended target.
Normally the target is a tumor below the skin of a cancer patient, but on this particular day it is a series of prescribed underwater points in a 50-gallon test tank. The tank, part of an array of quality-assurance tests, sits in the spot where cancer patients lay on the treatment bed.
|This 50-gallon water-tank testing tank is inspected by Richard Popple. The tank recently was moved to its new home in the Hazelrig-Salter Radiation Oncology Center. Each piece of radiation equipment was tested after the move.
The assurance testing measures the power and shape of the radiation beams, says Ivan Brezovich, Ph.D., chair of the Division of Radiation Physics in the Department of Radiation Oncology.
"The water-tank testing is a good approximation of the way radiation beams behave inside the body because humans are more than half water," Brezovich says. "We have to commission each piece of radiation equipment before its use, whether it's an existing piece of technology that has been moved or a new machine that has just been installed."
The latest test was performed for a radiation machine the department moved to its new home in the Hazelrig-Salter Radiation Oncology Center, housed under the same roof as the new UAB Women & Infants Center.
Brezovich and his division colleagues ensure the radiation is confined to its target in treatment rooms sealed with thick concrete shielding and that the building's power grid, safety locks and other machines work properly. The physicists also contribute to radiation treatment plans and conduct research.
Lately, the physicists are gathering reams of technical data and operational codes from relocated radiation machines to submit to state regulators who must approve UAB's request to treat patients with each moved or new machine. The first approval enabled treatments to begin March 9 in the Hazelrig-Salter center.
The move is nearly halfway complete, and it should be finished in July after crews relocate a machine from Wallace Tumor and install a new one still to be delivered, Brezovich says. In between, the radiation staff and equipment will be moved into the new center, including the department's radioactive materials used for more specialized treatments like implantable and injected radioactive isotopes.
Dawn of new day
When the final box is unpacked, the new center will be capable of delivering more than 30,000 treatments annually though the UAB Comprehensive Cancer Center's team-approach to care.
Radiation oncology Chair James A. Bonner, M.D., says this state-of-the-art treatment space reflects advancements and trends in his field that depend on a diverse mix of experts including oncologists, medical physicists, dosimetrists, radiation therapists, nurses, social workers and others. Oncology also has developed a new focus of multi-session, lower-dose treatments that more accurately target tumors and avoid healthy tissue. These treatments are often termed radiosurgery.
A majority of treatments given in the new Hazelrig-Salter center will be done with one of several linear accelerators referred to as a linac. Linac technology emits beams from hundreds of angles that can be adjusted and targeted based on detailed body scans. Most are equipped to follow real-time changes inside a patient, such as breathing and tumor movement.
"All this high-tech radiation technology starts with the physicists, even the design of the building," says Brezovich. He points to a set of well-worn Hazelrig-Salter center blueprints in his office, complete with safety and technical details.
Brezovich's division is a national leader in research and technical ability, propelling UAB forward in the use of leading-edge technology like radiosurgery and IMRT (intensity-modulated radiation therapy). One manufacturer already is negotiating with UAB to help premiere a new radiation-therapy system that could further revolutionize cancer care, says division physicist Richard Popple, Ph.D.
Popple says it is gratifying to work among five other physicists who contribute to patient care and continue to make strides in the science behind medical radiation. "Other cancer centers have only one physicist and they hope for the best," he says.