The inspection methods and systems of the present invention are mobile, rapidly deployable, and capable of scanning a wide variety of receptacles cost-effectively and accurately on uneven surfaces. The present invention is directed toward a portable inspection system for generating an image representation of target objects using a radiation source, comprising a mobile vehicle, a detector array physically attached to a movable boom having a proximal end and a distal end. The proximal end is physically attached to the vehicle. The invention also comprises at least one source of radiation. The radiation source is fixedly attached to the distal end of the boom, wherein the image is generated by introducing the target objects in between the radiation source and the detector array, exposing the objects to radiation, and detecting radiation.