X-ray apparatus, with a collimator arrangement (12a, 18, 28a) positioned between the focus point (12b) and the detector (28b), mechanics (43) for enabling motion of the collimator arrangement, the detector and the x-ray source along a scan trajectory (30) in a x-z plane (83) and also along curved scan trajectory (45), which partly extents along a y-axis (35) perpendicular to the x-z plane. By using this invention better tissue coverage of objects with curved edges can be obtained.