A CT system for scanning a patient is disclosed. In at least one embodiment, the system includes a tube/detector system, which can be set by a control device in respect of tube voltage and/or dose power; a patient couch, which can be displaced in a controlled fashion at least in the direction of a system axis; and a computer system, which can control the CT system. In at least one embodiment, the system includes an evaluation unit for a prescribed logical decision tree, which is integrated into the computer system, and which determines examination and scan parameters for the CT system on the basis of the input of at least one patient parameter described in a parameter list and operates the CT system using these examination and scan parameters.