A component of an x-ray system (diagnostic, therapeutic, radiation therapy simulator) intended to be placed on the floor to mount, support and facilitate positioning of the x-ray tube assembly (not included). It typically consists of a rack with controls mounted on a base plate. The x-ray tube assembly is attached to the rack and can be moved along the rack and/or tilted. Some designs also support the movement and positioning of an image receptor assembly (e.g., C-arm assembly).