Flat-panel CT device invades operating room

CT scanners are going places they have never gone before. One system is headed into the operating room.

Xoran Technologies' xCAT is being designed to take brain images of anesthetized patients to track progress made during surgery. Prototypes of the scanner have entered limited clinical use at the University of Pennsylvania and New York University. Dr. David W. Kennedy, director of rhinology at the Penn Health System, uses xCAT scans to update a computer-assisted navigation system.

"The low radiation dose makes it possible to scan a patient toward the end of a surgery and identify what, if any, disease we may have left, and then go and remove it while the patient is still asleep," said Kennedy, a pioneer of endoscopic sinus surgery in the U.S. and an early adopter of image-guided surgery. "I think that this opens new opportunities within the field of endoscopic sinus surgery."

The Ann Arbor-based start-up used research done at the University of Michigan to develop the scanner with grants from the National Institutes of Health. The xCAT system features a 30 x 40-cm flat panel mounted on a U-arm that rotates around the patient's head, while the patient lies motionless. Conebeam software reconstructs the data into 2D and 3D images of the brain at various points during surgery.

"It can acquire the entire volume of the head in one revolution," said Jackson Buell, marketing analyst for Xoran. "You don't have rows of detectors spinning around and the patient moving in and out. It just does it all at once."

The imaging chain revolves around the head of an adult in about 40 seconds and around the head of a child in about 20 seconds. Artifacts due to patient movement are not an issue during the scan, as the patient is anesthetized. Plates of transparent lead, mounted on each side of the U-arm to form a box, are designed to control radiation scatter.

When it becomes commercialized, possibly this summer, xCAT will join its smaller cousins, the mini-CAT, which is being marketed to allergists and ear nose and throat specialists, and the i-CAT, a CT designed for dentomaxillofacial imaging. These systems feature a flat panel about half the size or less of the one in the xCAT.

Whereas these other CTs are being sold into physician and dentist offices, the xCAT will be sold into hospitals, initially for applications in the operating room and possibly the intensive care unit. Just as the company's technologies have evolved, so might the medical applications of xCAT.

"Hopefully, as we get experience in some of the big hospitals, we'll learn some of the other things it can do," Buell said.