In a computer tomography system having an x-ray detector with a detector surface at which sensor pixels, for detection of x-ray radiation, are distributed non-uniformly, and a method for operating such a system, either a pitch factor is selected, and a value range for an extent of a reconstruction field for image data is determined dependent on the distribution of the sensor pixels and dependent on the selected pitch factor, or a value for the extent of the reconstruction field is selected, and a value range for the pitch factor is determined dependent on the distribution of the sensor pixels and dependent on the selected value for the extent of the reconstruction field.
