[LorenPechtel]

True, but they did nothing but talk for a little bit. If she was what they were looking for their actions would not have been of any value. In her case we had just walked through a metal rectangle--could simply have been something to narrow the line to one person wide, or there could have been something in it. I had thought it was lining people up for an infrared camera (I had previously seen such a station with a monitor that was clearly showing an IR camera view of the crowd) but they called her over.

This was Tc-99M, half life 6 hours, 140keV gamma emitter. Commonly used in imaging heart arteries.