Imaging systems and methods are provided for detecting object that may be hidden under clothing, ingested, inserted, or otherwise concealed on or in a person's body. An imaging assembly and mechanisms for vertically moving the imaging assembly may be configured to reduce the overall form factor of such imaging systems, while still retaining an ability to perform full/complete imaging of a subject. A calibration system assembly can be included, comprising a first calibration assembly and second calibration assembly to perform fine-grained adjustments to the positioning of the X-ray detector.
