The backscatter systems work by generating small
amounts of X-rays that reflect off the skin of an individual
placed in the scanner. The scattered ionizing energy of the Xrays
is then picked up by sensitive detectors and processed by
a computer to produce a two-sided image. The resulting image
is a revealing chalk-like outline that has been the cause of
debate since its implementation. The backscatter scanners
operate at 50 kVp producing X-rays with a tenth value layer
(TVL) of about 8 cm in tissue (Moulder, 2012). Transportation
Security Officers (in federal airports) or private contract
screeners (in nonfederal airports) operate these units and it
takes approximately 15 s to complete a scan. Traditional
backscatter scanners require one operator to direct the passenger
through the scanner while another operator is stationed
in a private location to analyze the image that comes
through to the computer. Rapiscan Secure 1000, manufactured
by Rapiscan Systems has an internal monitoring system
that prevent over exposure of X-rays to passengers. These
systems consist of sensors and detectors that enable the
scanner to default to a power-down state if it is not operating
within the set critical parameters