How about implants or pacemakers?IEEE Spectrum: X-ray Body Scanners Arriving at Airports
So anyone carrying a wallet could be pulled aside since they wouldn't know what, exactly, the item is
You're supposed to put all that sort of stuff aside in the bin before you go through...
Woman forced to remove prosthetic breast, And she's a flight attendant.
70 yr old man's pants removed over knee implant.
The list goes on..
No big: you have a pacemaker, then you say, "I have a pacemaker." Then you're checked out for having a pace maker.
Not rocket science.