X-ray diagnostic apparatus has a beam transmitter and beam receiver mounted opposite one another on a curved holder. In a first operating mode, the curved holder is formed by at least a first circular ring segment on which the beam transmitter and the beam receiver are mounted. In a second operating mode, a second circular ring segment is coupled to the first circular ring segment so that a closed ring results. Displacement arrangements, as well as energy supply connections, are provided for the beam transmitter and the beam receiver, and a signal transmission arrangement for the beam receiver is provided, so that the beam transmitter and the beam receiver can be controlled, positioned opposite one another, so as to rotate around an examination subject. With this X-ray diagnostic apparatus, both transirradiation exposures and computed tomography exposures can be produced.