A novel X-ray apparatus is provided for three-dimensional imaging and in particular for tomosynthesis examination, which includes an X-ray source having a focal spot, a collimator including a plurality of slits, a detector assembly including a plurality of line detectors corresponding to respective ones of the plurality of slits and an exposure volume arranged between the collimator and the detector assembly. The X-ray source, the collimator and the detector assembly are arranged in series, so that each line detector is aligned with the corresponding collimator slit and the focal spot, and is simultaneously displaceable by a scan motion relative to the exposure volume. The scan motion is primarily a rotation around a rotation axis arranged such that the detector assembly is situated essentially between the rotation axis and the X-ray source. Combined two and three-dimensional examination are also permitted according to the disclosed methods and apparatus.