Answer to reader question

Backscatter X-ray Technology:
"A passenger is scanned by rastering or moving a single high energy x-ray beam rapidly over their form. The signal strength of detected backscattered x-rays from a known position then allows a highly realistic image to be reconstructed. Since only Compton scattered x-rays4 are used, the registered image is mainly that of the surface of the object/person being imaged. In the case of airline passenger screening it is her nude form. The image resolution of the technology is high, so details of the human form of airline passengers present privacy challenges."

In answer to a question, here is a brief discussion of the backscatter x-ray imaging technology from the Electronic Privacy Information Center (EPIC - not to be confused with with another EPIC, the El Paso Intelligence Center of War on Drugs fame). Use the link to the EPIC site here and you will find links to dozens of news articles and other resources on this and related topics.