[en] Computed tomography, CT, has experienced a tremendous development during the 30 years since its introduction. The first equipment was only able to produce images of the skull. The acquisition time as well as the reconstruction time was between 2 and 10 minutes. Even though the image quality at this time was poor, the new technique proved to be so useful in medicine that the inventors Allan M. Cormack and Godfrey N. Hounsfield were awarded with the Nobel Prize in medicine 1979. Today the development of computers, mathematical algorithms, detectors and efficient x-ray tubes has made it possible to examine the whole body in less than 30 seconds and to produce 3D-images. This has lead to an increase of both the number of examinations and of the dose per CT-examination. (orig.)