The world’s first silicon-based photon-counting CT system, designed by GE Healthcare, is now under clinical evaluation in a pilot study overseen by Karolinska Institutet and MedTechLabs.
In photon-counting CT, detectors measure each individual X-ray that passes through a patient’s body. This allows it to collect more detailed information to better visualize organ structures, improve tissue characterization, make more accurate material density measurements and lower radiation dose. It is expected to significantly enhance imaging in oncology, cardiology, neurology and for many other clinical CT applications.
GE used pure silicon detectors developed by Prismatic Sensors, which it acquired in November 2020 for this very endeavor. Compared to other photon-counting CT detector materials, silicon is purer, more abundant and has broad manufacturing infrastructure. The main objective of the trial is to study the performance of the machine’s Deep Silicon detector technology, which combined with photon-counting CT has the potential to produce stronger spatial resolution. The study will also compare the performance of the photon-counting CT system with Deep Silicon to standard CT technology and collect insights for optimizing image processing.
"What makes photon-counting CT with Deep Silicon detectors so unique is that the resolution of the images can be greatly increased, and the dose of radiation reduced, which is particularly important for pediatric patients. You can, for example, determine the degree of constriction in a calcified blood vessel much more accurately, see smaller blood vessels than is currently possible and more easily identify a stroke in certain parts of the brain," Staffan Holmin, professor at Karolinska Institutet, consultant at ME Neuroradiology at Karolinska University Hospital, and clinical evaluation leader responsible for testing and optimizing the technology, told HCB News.
He adds that the system can also be used to image vascular pathologies and see malignant changes at earlier stages when treatment is more effective.
Silicon detectors have traditionally been too thin to stop and collect a sufficient number of X-ray photons when placed in a “face on” position. GE got around this by placing the silicon sensors “edge on”, which allows the detectors to handle the very high photon flux from the CT’s X-ray tubes. The sensors can count hundreds of millions of CT photons per second to create sharper images than standard CT.
The research group will perform additional studies with a larger number of participants to explore the potential for improving image quality. They will also look at pattern recognition (AI), data management and optimization of visual information to help radiologists better assess the state of diseases for different parts of the body.
"GE Healthcare is working diligently to advance its capabilities through clinical evaluation and, once satisfied with its performance, will expeditiously deliver a clinically viable photon-counting CT system with Deep Silicon detectors," Sonia Sahney, chief marketing officer of molecular imaging and computed tomography at GE Healthcare, told HCB News.
Additionally Siemens just launched
a new photon-counting CT scanner, NAEOTOM Alpha. Cleared for clinical use in the U.S. and Europe, the solution uses photon-counting to produce detailed 3D images and has a Dual Source design for working fast and can remove obstructions caused by calcifications.
Canon is also looking at the potential around photon-counting CT by partnering with the National Cancer Center Japan and EAST Hospital
in Kashiwa to conduct research on its use. The three plan to use the quantitative capabilities of the technology to assess treatment effects from chemotherapeutic agents on malignant tumors. They will also analyze different tissue characteristics for clinical insights in different medical fields.