Rapiscan backscatter scanners use low-dose x-rays to do the same.

BBC: Radiation-free full-body scanners

The TSA plans to deploy 1, 275 backscatter and millimeter-wave scanners covering more than half its security lanes by the end of 2012 and 1, 800 covering nearly all the lanes by 2014.

FORBES: Europe Bans Airport Body Scanners For "Health and Safety" Concerns

But Congress voted to require all body scanners to have privacy-protecting software, and the TSA announced in February it was phasing out backscatter systems because they could not meet the new standard.

CNN: TSA removes body scanners criticized as too revealing