New Spiral CT Techniques May Cut Cost, Refine Capabilities

 NEW YORK—The main challenges in the continuing development of low-dose spiral CT screening for lung cancer are “cost, flow, and efficiency,” Stanley H. Fox, PhD, General Electric Med Systems, Milwaukee, said at the Second International Conference on Screening for Lung Cancer.

With today’s technology, Dr. Fox said, the cost target per screening CT scan is about $75. With improvements, he added, that should eventually drop to $50. “We believe we can screen up to 10 to 12 patients an hour, cutting the cost dramatically,” he said.

The company is focusing on the flow process as one way to increase efficiency. Diagnostic and high-resolution studies, if needed, Dr. Fox noted, should be performed immediately after the initial low-dose study. “You don’t have to reposition the patient,” he said. “You don’t have to call him back. You can save a lot of trouble.” Building this capability into the system is “probably the biggest challenge here,” he said.

Another key element is computer-aided diagnosis. Equipment is being designed to quantify any changes seen between screenings and to include a database that will permit autoregistration with prior lesions. Vessel and bronchi tracking may also be built in. “In fact,” Dr. Fox said, “we may present all of this in a volumetric display.” A total electronic record-keeping system is mandatory, he stressed.

In the rapid-fire CT mode, Dr. Fox said, one touch of a button should set up the scanner. Automatic exposure control is being built in, he added. Techniques to help reduce artifacts and “noise” in the images are also being developed.

With today’s scanners, the patient moves horizontally. In the future, however, the table on which the patient is positioned may move up and down as well, Dr. Fox said. This innovation, he predicted, might enable a CT scan to be performed as quickly as a chest x-ray, if not faster.

Higher resolution is also being investigated. The effective size of 1 × 1.25 mm at the isocenter may in time drop to 0.2 × 0.2 mm, Dr. Fox said, and slices per centimeter might rise to 20 or 25.

“We believe that lung cancer screening is going to happen,” he said. In addition, he noted, technologic improvements to advance lung cancer screening apply “to chest radiology in general and will be very useful in routine diagnostic work.”