Next week, the Transportation Security Administration will begin using the latest generation of full-body scanners, the agency's newest defense against a deadly terrorist weapon - a carry-on bomb, reports CBS News correspondent Bob Orr.
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First to put them to the test will be Boston's Logan International Airport, where 10 of the 9/11 hijackers boarded planes that crashed into the World Trade Center.
The full body X-ray scanner - the first of 450 new machines being deployed across the United States - will start screening passengers Monday for hard-to-detect explosives.
In a demonstration, screener Kelly McLain spots a potential danger. She's suspicious of something on a passenger's body and sends the passenger to a body scanner, where she can check her suspicions against an X-ray image.
Lee Kair, TSA's assistant administrator for security, told Orr that the image won't be spread among the security staff.
"Absolutely not," Kair said. "The only person who sees it is one individual back in the remote viewing area."
Acting TSA Administrator Gale Rossides said the images are not kept.
"These images cannot be stored," Rossides said. "An officer cannot print off the image. So as soon as that analysis is made of that image, that image is destroyed."
Still, privacy advocates ridicule the scanner as an ineffective "virtual strip search."
"This is kind of security theater," said Christopher Calabrese of the American Civil Liberties Union. "I mean, terrorists are going to be able to find places where these are not in place. You're not going to be able to get them everywhere."
There are 40 body scanners that use a different technology already in place, like at Miami International Airport. This new wave of 450 will bring the total to 490 full-body scanners, not enough for the roughly 2,100 airport security lanes in the United States.
To cover the gap, the TSA will rely on a random selection process. When passengers arrive at a checkpoint, some will still go through standard metal detectors while others will be sent for full-body scans.
There are also questions about effectiveness. The Government Accountability Office recently concluded it was "unclear" if the scanners would have detected the underwear bomb Umar Farouk Abdulmutallab smuggled aboard Northwest Airlines Flight 253 on Christmas Day.
Technology rushed to the security front has not always worked either.
The U.S. spent $36 million on 200 explosive-detecting puffer machines which ultimately proved unreliable.
Security officials say the X-ray scanners will work, but they know terrorists are already looking for vulnerabilities.
"They are very adaptive," Rossides said. "They are very smart. They are studying what we do."
One more point: passengers can refuse the full-body scan, but those who do will receive a pat down.