The full-body scanner has arrived at Philadelphia International Airport. Passengers going through the Terminal F security checkpoint now have an option of using the new technology, or sticking with a walk-through metal detector - followed by a pat-down.

Travelers' reaction, as they lined up to go through security Thursday: It's no big deal.

"Hey, you've got to try everything new, no?" said Antonio DiMaria, who was flying home to Montreal after a business trip to Philadelphia. "It's better. You won't have these planes falling into buildings anymore, so why not."

The new technology can detect both metallic and nonmetallic items - such as explosives and plastic weapons - concealed under clothing. "A walk-through metal detector, as the name implies, only detects metal," said Ann Davis, spokeswoman for the Transportation Security Administration.

Fellow traveler Jack Ledoux, who also was heading home to Montreal, said he has tried the scanner at another airport. "It's fine for me. It adds security and is faster" than a metal detector and pat-down.

"It's fine with me," said Tippee Allender, an account executive from Greenville, S.C. "I'd rather be safe on this flight. I know I'm not carrying anything concealed. I'll go through it. I'd rather go through the machine than be patted down."

Bill Meinel, a software engineer for Comcast from Bensalem, said, "I couldn't care less. If you are in the Navy, you go through all this stuff. It doesn't bother me. But let me ask a question: Do I still have to take my shoes off?" (The answer is yes.)

None of the half-dozen passengers at the security check about 2 p.m. objected to full-body imaging, which started being used about 3:30 p.m. Wednesday in Philadelphia airport's busiest terminal, handling express and regional flights.

Near the conveyor belt for bags and carry-ons was a sign, showing front and back views of a scan image. The sign noted that the equipment was optional.

"Anecdotally, I've heard that people appreciate there is an option," said Deborah Ostreicher, spokeswoman for Sky Harbor International airport in Phoenix, Ariz., the first U.S. airport to get the technology, in November 2007.

The millimeter wave technology that scans a traveler and the robotic image that is generated had mixed reviews initially, Ostreicher recalled. In the last three years, she said, she has not heard anything specific regarding objections or controversy.

Philadelphia will get more body-scanners in coming weeks. "I don't have a solid number for Philadelphia," Davis said. "They will be distributed throughout the airport."

Nationwide, 317 whole-body scanners are being tested and used in 65 airports.

The TSA says 99 percent of passengers opt to use the machines.

"We have seen a very high acceptance rate at airports," Davis said. "Passengers have mostly positive remarks. Many people understand the need for it, and are happy to go through."

The TSA says passenger privacy is ensured through the anonymity of the image. Facial features are blurred. The body image resembles a fuzzy photo negative, or a chalk etching, Davis said.

The TSA security officer working with a passenger does not see the image, and the officer viewing the image is in another location and does not see the passenger.

Officers communicate wirelessly over a headset to clear the passenger for travel.

The images cannot be stored, transmitted, or printed, and are deleted immediately once viewed, the TSA website says. The machines have zero storage capacity, according to the website.

Privacy advocates have expressed concern that the technology performs a virtual strip search and produces "naked" pictures.

The Washington-based public interest research center Electronic Privacy Information Center filed a lawsuit, asserting that the scanners "produce detailed, three-dimensional images of individuals." The group asked the District of Columbia Court of Appeals to suspend the TSA's scanner program as "unlawful, invasive, and ineffective."

"We went to great lengths to listen to the privacy concerns," Davis said. "We worked closely with the equipment manufacturers to install privacy filters that are now in place."

Travelers can see sample images on the TSA website at www.tsa.gov and go to advanced imaging technology.

Whole-body imaging machines are still in the pilot phase. The goal is to install 450 machines in airports by the end of this year, and 500 more in U.S. airports by the end of 2011, Davis said.

"It's the best available technology to detect items concealed under clothing, and it is 100 percent optional," Davis said. "It is a more sophisticated way to get at those threats, as opposed to using the other technology we have available, and performing a pat-down."

Contact staff writer Linda Loyd at 215-854-2831 or lloyd@phillynews.com.