The threading of slender catheters and stents through arteries to deliver treatments to the heart, the brain and elsewhere in the body has produced nothing short of a medical revolution.
But these delicate procedures require that patients be exposed to continuous radiation that can last up to an hour or more, sometimes causing skin injuries that, in rare cases, develop necrosis (tissue death), requiring skin grafts.
Now University at Buffalo researchers, working with an Amherst, N.Y., startup company called Esensors have developed a unique, real-time patient dose-tracking system, which lets physicians know when the accumulated radiation dose is approaching a dangerous threshold.
The system is designed to be used either as a retrofit with existing fluoroscopy machines or to be included in the design of new machines.
Funded by grants totaling $814,000 from the U.S. Food and Drug Administration under the Small Business Innovation and Research program, the team of researchers is completing a prototype that will be clinically site-tested prior to commercialization.
"Our system provides complete tracking of actual radiation levels on the skin, providing both instantaneous dose rate, as well as cumulative exposure," explained Daniel Bednarek, Ph.D., UB project director, researcher at UB's Toshiba Stroke Research Center, professor of radiology and research associate professor of neurosurgery and biophysics in the School of Medicine and Biomedical Sciences.
Development of the system was spurred by a growing concern among physicians and by advisories issued by the Food and Drug Administration's Center for Devices and Radiological Health warning of occasional, but severe, radiation-induced skin injuries during prolonged, fluoroscopically guided invasive procedures.
"It can take a long time to insert a catheter into the brain and perform a complicated endovascular treatment, for example," explained Bednarek, also an adjunct professor in the Department of Physics in UB's College of Arts and Sciences. "Patients undergoing such procedures sometimes develop erythema – redness – hair loss or even skin necrosis in the exposed area."
These effects can result whenever long fluoroscopic times are used during interventional procedures, such as coronary angioplasty, stent placement, radiofrequency cardiac ablation and vascular embolization.
"With the equipment that currently is being used, the physician can minimize the chance for burns by moving the X-ray source instead of keeping the intensity on one spot," explained Darold Wobschall, Ph.D., UB professor emeritus of electrical engineering and president of Esensors. "The problem is that the physician is concentrating on the surgery and with X-rays coming in, he or she would have to be keeping mental track of where the dose is occurring at the same time."
"Our system solves that problem," said Wobschall.