"It is very likely that a large (15-20 cm in diameter), irregularly-shaped, cm-thick pancake with beveled edges, taped to the abdomen, would be invisible to this technology, ironically, because of its large volume, since it is easily confused with normal anatomy," the study explains.

...manufacturers of airport scanners positioned contraband like guns, knives and drugs in unnatural ways to conceal the limitations of their device. For example, the simulated drugs are always packed into tight rectangles that show up distinctly on the machine. TSA employees would have a far more difficult time spotting less tidy terrorists. "