Many people with prosthetic limbs complain about the CastScope, a screening device, that uses backscatter X-ray technology to identify security threats concealed in a prosthetic, cast or bandage. They say they're concerned about radiation exposure, the length of time it takes to be screened and a lack of qualified personnel operating the devices.

In June, the Amputee Coalition of America expressed its concerns about the CastScope and called on the Transportation Security Administration to "clean up its act" when screening people who've lost a limb. The group, which has about 5,300 members, says a survey of 7,300 amputees finds they've been subjected to "inconsistent, unfair, abusive and often embarrassing screenings" by TSA personnel.

"One of my biggest peeves is the CastScope," says Jeffrey Cain, a doctor and chief of family medicine at The Children's Hospital in Denver, whose legs were amputated below the knee. "It takes a long time, some screeners don't know how to operate it and, as a frequent flier, I'm concerned about the potential cumulative dose of radiation."