A computed tomography (CT) system for scanning an object comprises a high energy X-ray source arranged opposite at least one detector subsystem and a transport mechanism to move the object through the system. The source and at the least one detector subsystem move together around the object in an arcuate trajectory and in a scanning step they rotate around the object though an angle after which the direction of rotation is reversed and a subsequent scanning step follows in the opposite direction of rotation. The arcuate trajectory may range from 20 to 270 degrees. The angle may be: sufficient for reconstructing a CT image； less than 180 degrees plus a fan beam angle and a laminographic image is reconstructed. The detector subsystem may comprise a plurality of detector arrays or a multi-slice detector. The object may be: kept stationary during rotation but moved incrementally between rotations； moved along a conveyor at a speed modulated by the speed of rotation so the conveyor speed varies linearly with the speed of rotation. The X-ray source may be a dual energy source. The system may be contained within a vehicle comprising a conveyor or ramp for transporting the object from outside the vehicle.
