A whole-body transmission x-ray scanner includes an x-ray source, an x-ray camera, a controller, and a positioner aligning the source and camera to point x-rays towards the camera and moving the source and camera synchronously to scan and acquire radiographic images of an object located therebetween. The positioner includes a closed-loop cable alignment assembly fixed to the source and to the camera to maintain alignment of the source and camera during a scanning mode in which the source and camera move from one end of the object to another end. The positioner includes a motor controlled by the controller, a bi-directional crossover slide track bearing assembly connected to the source, and a conveyor connected to the motor and bearing assembly such that, actuation of the motor by the controller moves the slide track bearing assembly in a loop that correspondingly move the source and camera along a single linear axis.
