Umar Farouk Abdulmutallab tried to blow up the plane using explosive powder strapped to his leg. Security experts say a body imaging machine probably would have detected the explosives before Abdulmutallab had a chance to board the flight.
Unlike the standard metal detector, which finds any metal on the outside as well as the inside of the body, the body image technology finds things only on the outside.
"What it shows is dark spots. Whole-body imaging can tell if you have plastic or powders or anything that would cause harm to an aircraft if you have it taped to your body," said a TSA official.
But critics compare it to a "digital strip search." According to a lawsuit filed by the Electronic Privacy Information Center advocacy group against the Justice Department, the technique compromises privacy by letting screeners "peer through clothing and capture detailed, three-dimensional images of individuals completely undressed."
The TSA says that's not completely true. It argues the image that is captured is as clear as a "fuzzy photo negative." The TSA's Web site also says it protects passengers' privacy by obscuring all faces, and that the screening officer who helps the passenger through the process never sees the image. Instead, the image is examined by an officer at a remote location who never sees the passenger.
"The two officers communicate via wireless headset," explains the TSA site. "Once the remotely located officer determines threat items are not present," the passenger can leave, and the image is automatically deleted.
Nineteen U.S airports use the imaging machines. Only 13 use them as an alternative to pat downs in secondary screening. Six use them for primary screening -- San Francisco, Salt Lake City, Miami, Albuquerque, Tulsa, Okla., and Las Vegas.
Read more on OpposingViews.com: Expect TSA Strip Search Photos to End Up on TMZ