[Principles of multidetector-row computed tomography. Part 2: determinants of radiation exposure and current technical developments].

In the field of multidetector-row computed tomography (MDCT) technical improvements have constantly extended the range of clinical applications and made new radiodiagnostic indications accessible. Whereas previous technical improvements were primarily aimed at the imaging of anatomy with high spatial and temporal resolution, nowadays a trend towards quantitative and functional imaging using computed tomography (CT) beyond the pure depiction of morphology is on the horizon: Currently the focus of technical developments is in the domain of spectral (energy-resolved) CT imaging and in the introduction of very wide multi-row detectors with large z-coverage. In addition, there is great interest in technical approaches for reducing radiation exposure of the patients caused by (spiral) MDCT, as the increasing range of its clinical applications as well as some of the recent technical advances involve the risk of increased radiation exposure. The use of iterative image reconstruction techniques in MDCT represents a particularly promising technical approach for the reduction of radiation exposure.