A method operates an x-ray system for examining an object. In order to optimize the operation of an x-ray system, in particular the dose regulation and/or the image processing, the following method steps are performed. Radiation is passed through the object to be examined and a number of fluoroscopic images of the object are generated. A relevant image region of a fluoroscopic image is selected by a user of the x-ray system. An image-based dose regulation of the radiation dose used for passing radiation through the object is carried out using the selected image region and/or image processing is carried out using the selected image region.