While the agency had spent over a billion dollars deploying the scanners at more than 160 airports around the country, an outcry over the scanners’ ability to show the airport security personnel manning the machine an outline of passengers' ‟junk” eventually led to the government scrapping the system, which was the primary means of ensuring security on airplanes from 2009 through 2013.
When the scanners first rolled out, the results of tests of their efficacy conducted both by Rapiscan and government officials were never made public due to security concerns, nor were any units of the full-body, backscatter X-ray machines made available for third-parties to run their own independent trials. Now that the machines are no longer in wide use in airports—they are still, however, common in government faciliteis around the country like courthouses and prisons—the researchers picked up a used one on eBay (where else?) and decided to take it for a spin.