An X-ray imaging system element (3) includes two compression elements (8a, 8b), which are movable relative to one another. An object (10) is introducible and compressible between the compression elements. At least one of the compression elements is adapted to alter its geometrical shape and/or alignment relative to the other during compression. At least one partly X-ray opaque marker element (24) is provided on one of the compression elements, which marker element is adapted to allow detection of an alteration of the geometrical shape of the respective compression element (8a, b).
