Radiation scanning systems to inspect objects are disclosed comprising a first vehicle supporting a radiation source. A second vehicle supports a detector. The source and the detector may be moved to scan an object, such as a cargo conveyance, between the vehicles. The first and second vehicles may having an expandable length and the source and detector may be moved across the expandable length, to scan long objects. The radiation source may be adapted to emit a vertically diverging beam of radiation, such as a fan beam. The radiation may be X-ray radiation, for example. The vehicle may comprise a truck and an expandable trailer releasably coupled to the truck. The trailer may comprise telescoping rails. The first and second vehicles may be driven to an inspection site, where they may be rapidly deployed. Methods of inspecting objects are disclosed, as well.