X-ray Imaging

 https://www.allaboutcircuits.com/news/clinical-trials-suggest-new-x-ray-photon-counting-detector-improve-diagnoses/

Clinical Trials Suggest New X-Ray Photon-Counting Detector May Improve Diagnoses

September 19, 2020 by Luke James

Researchers at CEA-Leti have developed a novel X-ray photon-counting detector that has been integrated into an X-ray scanner with promising initial trial results.

As part of a collaboration with Siemens Healthineers, researchers at CEA-Leti have designed a novel x-ray photon-counting detector module (PCDM) and integrated it into an X-ray computed-tomography (CT) scanner prototype manufactured by Siemens. 

Now, according to a CEA-Leti press release, initial clinical trials have demonstrated the technology’s promise as a solution that could improve CT scanning by increasing spatial resolution, enhancing image quality by lowering noise, and reducing the amount of X-ray exposure that patients are subject to during a scan.

X-Ray PCDMs Based on Cadmium Telluride

Conventional semiconductor-based photon-counting detectors (PCDs) consist of two core components: a semiconductor material such as silicon (or as is the case in this study, cadmium telluride) with two electrodes and application-specific integrated circuits (ASICs). 

Current X-ray CT scanners produce their images with energy-integrating detectors that are based on indirect conversion technology. In this study, CEA-Leti leveraged its simulation tools to design the PCDM’s geometry and select a semiconductor based on cadmium telluride (CdTe).

The X-ray photon-counting detector module

The X-ray photon-counting detector module. Image used courtesy of CEA-Leti

 

In contrast to current technology, CEA-Leti's PCDMs directly convert x-ray photons into electronic currents with high conversion yields. As such, CdTe-based X-ray PCDMs are said to enable simultaneous acquisition of high-spatial-resolution and multi-energy images.

This higher resolution improves the quality of X-ray imaging by using a small-pixel size detector. At the same time, multi-energy provides color images and enables a precise determination of the atomic number of any chemical elements that are present in the body.

 

The Future of Detector Modules?

Following an evaluation of the PCDM system’s performance in humans, animals, and cadavers, researchers found that it delivers significant improvements on spatial resolution, decreased radiation or iodine contrast dose requirements, and decreased image noise levels and other disruptive artifacts.

As an example of the effectiveness of the PCDM system, it’s capable of generating much clearer images of fine structures in the human body, such as small airways in the lungs. 

 

CT scans use a series of X-rays to captures cross-sectional images of the body

CT scans use a series of X-rays to captures cross-sectional images of the body. Image used courtesy of Mayo Clinic

 

Images of more than 300 patients produced with the technology yield “a number of important clinical benefits,” said Cynthia McCollough of Mayo Clinic. She went on to add that the ability to simultaneously acquire multiple 150-micron-resolution datasets, each of which represents a different energy spectrum, could lead to new clinical applications in addition to improving medical diagnoses.

“The successful collaboration with CEA-Leti allowed Siemens Healthineers to prototype what the med-tech company sees as the future of detector modules for whole-body CT,” says Jean-Michel Casagrande, the project manager for medical X-ray imaging at CEA-Leti.