The Transportation Security Administration uses something called millimeter wave technology for its full-body scanners at a growing number of U.S. airports including RDU's Terminal 2 ("RDU's new scanners see down to the skin").
It's hard to know just how explicitly the scan records the details of your sex, your surgical scars, and the rest of your body. You can certainly tell the boys from the girls.
One TSA official told USA Today: "You can actually see the sweat on someone's back."
Click the image above for a larger version of the low-rez sample photo provided by TSA.
Read the ACLU's take on body scanners and "virtual strip searches."