The invention is based on the idea of automatically selecting, by a patient-specific value is called in the internal memory of a first computer at least, wherein the patient-specific value may in particular be a measure for the expected X-ray absorption by the patient, a scan protocol for tomographic image of an X-ray image of a patient to compare, and this patient-specific value with stored reference values available automatically, each reference value is assigned to a scanning protocol. Finally, the automatic selection of a scanning protocol by means of the first computer on the basis of the comparison according to the invention is carried out. By automating the selection of the scan protocol selection is simplified because no manual selection of the scanning protocol must be made according to the invention. Furthermore, the present invention automatic selection of a suitable scanning protocol is faster than a manual selection.