1. An X-ray device, comprising: an X-ray source that emits X-ray radiation; a flat-panel X-ray detector that is rotatable about a common axis of rotation with the X-ray source for acquiring image data of an object, wherein the flat-panel X-ray detector is subdivided into a first part and a second part by a plane that is perpendicular to the flat-panel X-ray detector and has the axis of rotation runs through the plane; and a processing unit that generates: a first 3D image reconstruction using image data acquired by the first part of the flat-panel X-ray detector, a second 3D image reconstruction using image data acquired by the second part of the flat-panel X-ray detector, a 3D image reconstruction using the first 3D image reconstruction and the second 3D image reconstruction, wherein the X-ray source comprises a first X-ray source and a second X-ray source, and wherein the first X-ray source and the second X-ray source are disposed mirror-symmetrically with respect to the plane so that the first part of the flat-panel X-ray detector only receives a first X-ray radiation emitted from the first X-ray source and the second part of the flat-panel X-ray detector only receives a second X-ray radiation emitted from the second X-ray source that is different from the first X-ray radiation.