13. September 2017

DECTRIS introduces Spectral Efficiency

The primary goal of every X-ray medical imaging modality is to deliver high quality images and thus enable a successful diagnosis. This in turn can boost the confidence of the radiologist and reassure the examined patient. High quality and precision imaging leads us to the heart of every X-ray imaging machine: the detector.

DECTRIS is renowned for producing cutting edge Hybrid Photon Counting (HPC) detectors for synchrotrons and scientific purposes. Today DECTRIS (P. Trueb et al. (http://onlinelibrary.wiley.com/doi/10.1002/mp.12323/full) introduces a novel detector performance quantity called Spectral Efficiency and applies this concept towards advanced spectral medical imaging techniques.

Conventional detectors used in medical radiology until today can be compared to black and white photography. Thus, the quality of a black and white medical image is assessed based on how effectively it replicates the anatomical structure of interest. But even in the case of a perfect black and white image one essential piece of information is missing: color.
DECTRIS’ mission is to successfully deliver the future of clinical spectral X-ray imaging detectors with single-shot material decomposition capabilities. To design and optimize spectral detectors for a range medical application, a deep understanding of several overlapping physical processes and parameters is needed. Furthermore, a quantity is needed to evaluate the detector’s spectral performance.

This new quantity is called Spectral Efficiency. Each photon has an energy and Spectral Efficiency describes the fraction of photons detected at their true energy. Our article published in Medical Physics reports the excellent agreement between measurements and simulations for quantities such as Spectral Efficiency, Quantum Efficiency and count rate using a prototype HPC detector with 75 x 75 µm2 as illustrated in the figure below. The custom DECTRIS Monte Carlo simulation reproduces accurately the measured spectra even at highest count rates by incorporating pile-up effects. Through Spectral Efficiency and the experience of our product development team, we optimize the next generation of our imaging detectors to suit your spectral imaging application.

Measured and simulated Spectral Efficiency of a 75 x 75 µm2 pixel as a function of the photon energy [P. Trueb et al. (http://onlinelibrary.wiley.com/doi/10.1002/mp.12323/full)]

Original publication
Trueb P, Zambon P, Broennimann C. Assessment of the spectral performance of hybrid photon counting x-ray detectors. Med Phys. 44(9), 2017. e207-e214.