A scanning-based apparatus for obtaining tomosynthesis data of an object performing a periodic movement comprises a radiation source emitting radiation around an axis of symmetry; a radiation detector comprising line detectors, each being directed towards the divergent radiation source to allow a ray bundle of the radiation that propagates in a different angle to enter the line detector after having been transmitted through the object, and to be detected repeatedly therein; and a movement device provided for moving the radiation source and the radiation detector relative to the object linearly in a path orthogonal to the symmetry axis, and a distance which is sufficient for scanning each of the line detectors across the entire object. The movement device is provided to repeat the movement a plurality of times, each time with a different phase shift relative to the periodic movement of the object.