A method and system for operating an x-ray device for a creation of a three-dimensional angiography of a body vessel segment. A three-dimensional reconstruction of the body vessel segment is provided to a computing device of the x-ray device. A center line of the body vessel segment is computed. An axis of rotation is laid through the center line. The three-dimensional reconstruction is registered with the x-ray device. The suitability of at least one recording angle pair with a first and a second recording angle for the creation of the three-dimensional angiography is assessed on the basis of an assessment criterion by the computing device. One of the at least one assessed recording angle pairs is selected for creation of the three-dimensional angiography as a function of a result of the assessment, in order to improve the creation of the three-dimensional angiography.