Technical background of a novel detector-based approach to dual-energy computed tomography

Abstract

Dual-energy information in computed tomography (CT) can be obtained through different technical approaches. Most available scanner designs acquire scans at two different x-ray spectra. Recently, the first detector-based approach became clinically available. Here, we review the physical principles of dual-energy CT (DECT), including the interaction of photons with matter in terms of the photoelectric effect and Compton scattering. We describe the available concepts to DECT and present a detailed description of the spectral detector CT system. We discuss the stacked detector design and its inherent technical advantages and disadvantages, as well as the principles of image reconstruction, their possibilities and limitations. The increase in reconstructions and data pose some challenges to both clinical and technological workflow, which are hereafter addressed. Finally, we discuss the detector-based approach in light of other, emis-sion-based DECT approaches.