A scanning unit for identifying contraband within objects, such as cargo containers and luggage, moving through the unit along a first path comprises at least one source of a beam of radiation movable across a second path that is transverse to the first path and extends partially around the first path. A stationary detector transverse to the first path also extends partially around the first path, positioned to detect radiation transmitted through the object during scanning. In one example, a plurality of movable X-ray sources are supported by a semi-circular rail perpendicular to the first path and the detector, which may be a detector array is also semi-circular and perpendicular to the path. A fan beam may also be used. Radiographic images may be obtained and/or computed tomography (“CT”) images may be reconstructed. The images may be analyzed for contraband. Methods of scanning objects are also disclosed.