[Spectral computed tomography in the age of photon-counting X-ray detectors].

Background: Since its introduction, spectral computed tomography has become an integral part of clinical imaging with a variety of possible applications. Over time, technical innovations have considerably improved the spatial and energy resolution. The recent introduction of computed tomographs utilizing photon-counting x‑ray detectors has opened up further applications, which need to be investigated regarding their clinical utility.

Objectives: This article gives an overview of the development of spectral computed tomography in general and photon-counting computed tomography in particular, with a special focus on recent technical developments and their clinical applications.

Conclusion: Very likely, photon-counting X‑ray detectors will over time prevail over conventional energy-integrating detectors. Most technical problems hindering clinical use have been overcome, so that the unquestionable advantages outweigh the remaining disadvantages. Further developments especially of detector electronics, reconstruction algorithms and software-based postprocessing will further support its clinical introduction.