In one example, a scanning unit for examining contents of a cargo container is disclosed comprising a first path through the scanning unit for transport of a cargo container and one or more sources of respective beams of radiation. At least one of the one or more sources are movable across a second path transverse to the first path. The second path extends partially around the first path. The scanning unit further comprises a detector extending partially around the first path. The detector is positioned to detect radiation interacting with the cargo container during scanning, such as radiation transmitted through the container. The at least one source and the detector are positioned so that the cargo container is transportable along the first path, between the source and the detector. A transport system may be provided to convey the object through the scanning unit, along the first path.