An X-ray imaging system includes an X-ray tube (6), a ceiling suspension (2) for the X-ray tube, a detector trolley (12) with an X-ray detector (10) mounted thereon, an active sensor matrix (24), an optical indication unit (20) and a control unit (26). The active sensor matrix (24) is fixedly mounted on the ceiling suspension (2), the optical indication unit (20) is fixedly mounted to the detector trolley (12) and is adapted for emitting an optical indication (22) onto the active sensor matrix (24). The control unit (26) is connected to the active sensor matrix (24) and is adapted for acquiring the position of the optical indication (22) on the active sensor matrix (24) and to create control signals for aligning the detector trolley position and the ceiling suspension position relative to each other.
