GE HealthCare has installed Stanford's first photon-counting and whole-body CT scanner. (Photo courtesy of GE HealthCare)

GE HealthCare's photon-counting CT prototype adopted by Stanford radiologists

October 18, 2023
by John R. Fischer, Senior Reporter
Radiologists at Stanford Medicine have begun scanning human subjects with GE HealthCare’s photon-counting CT prototype designed with Deep Silicon detectors, as part of ongoing clinical trials investigating how well the technology improves image quality and insights derived with it optimize utilization rates.

The technology is designed to provide more data to improve patient outcomes across oncology, cardiology, neurology, and other clinical CT applications, and is the first photon-counting CT and whole-body scanner at Stanford Research Park. The researchers will assess reconstruction methods, image presentation workflows, and clinical benefits for specific pathologies and disease types.

Photon-counting CT decreases pixel size and improves spatial resolution in images by converting individual X-ray photons into an electrical signal. It also has higher dose efficiency, allowing for ultrahigh-resolution images of large areas of the body to be captured, and can potentially visualize minute details in organ structures, improve tissue characterization, and provide more accurate material density measurements or quantification.

"With the ability to measure the energy of each photon, it may provide more accurate material density measurement (or quantification) information important for differential diagnosis. This is critical, as physicians rely on the information they receive from medical images to help correctly diagnose patients, monitor cases, and make treatment decisions," Chad Rowland, general manager of premium CT and photon-counting at GE HealthCare, told HCB News.

In 2020, GE Healthcare acquired Prismatic Sensors AB, a Swedish startup specializing in silicon detectors for photon-counting CT. These silicon detectors are designed to enhance spatial resolution without compromising spectral resolution.

GE HealthCare, which has been studying photon-counting CT since 1993, uses pure silicon detectors that are placed “edge on” to overcome the historic challenge of silicon being too thin to collect a sufficient number of X-ray photons. In this position, the detectors can manage the very high photon flux (quantity of information) from the CT’s X-ray tubes, allowing them to absorb very high-energy photons fast enough to count hundreds of millions of CT photons per second, creating crisper images.

The company began clinical trials with the technology in 2021 with Karolinska Institutet and MedTechLabs in Sweden. Last December, it introduced the first U.S. trial at the University of Wisconsin–Madison, using a new prototype with a larger detector that can possibly speed up scanning time and expand coverage; ECG-gated cardiac scan capabilities for coronary artery imaging; and faster acquisition speed for reducing the chance of blurred images due to motion.

The prototype at Stanford Medicine includes some hardware and software improvements based on insights provided by UW—Madison, Karolinska Institutet, and MedTechLabs.

The technology is under development and is not cleared or approved by the FDA or any other global regulator at this time.