Millimetre-wave thermography is used to image through the soles of shoes as proof of
principle study into the application of such an approach for security inspection. Current airport security
screening practice necessitates the removal of shoes prior to x-ray screening for potential threats or
other concealments, for example explosive or explosive precursor materials; narcotic substances or small
weapons. The authors demonstrate that thermography at ∼ 250 GHz is able to reveal a variety of
objects concealed within the soles of typical shoes, and that such an approach might be applied to
rapidly screen passengers without necessitating the removal of their footwear.