Yes, as stated above, back scatter X-ray machines have been removed. They produce much higher quality images than millimeter wave scanners, but expose you to small, but non-zero amounts of ionizing radiation. Also, as mentioned, their software did not have the automatic detection feature that prevents humans from seeing the images. Millimeter wave imagers have lower resolution and, at these frequencies the human body looks mirror-like, so the images look like a shiny statue.
As Chronos mentioned, these are not “high energy photons”. In terms of equivalent temperature, visible light, which bathes us all the time, represents the temperature of the surface of the sun. Millimeter waves represent the temperature of a few degrees above absolute zero. If you are worried about that, I hope you aren’t standing near someone using a cell phone, which puts out much higher power levels than millimeter wave scanners.