[en] The BT-S4 unit consists of a support suspended from the ceiling on which the X-radiator is fixed, a Bucky table with floating plate, and an integrated device for tomographic movements in two dimensions. The blowing device is driven by two motors in the suspended support. Coupling between focus and detector path is assured by a rod, which can be decoupled, the fulcrum being stationary. The layer is selected by adjusting the distance from table to detector. Both for radiographic and tomographic purposes the device can be furnished with a system function, jointly with the generator, for automatic exposure. (orig./HP)