I don't think that everyone is on the same page here as far as use of xray technology on people. Things like the RapidScan xray system, newly in use at airports, was not in use at public buildings in the US "for years." It is too new to have any assurance about it's safety.
PPs likely have it confused with the metal detectors. Can any of the PPs provide some links to back up their assertions that xrays and microwaves have been used on people for a long time?
Xray technology has been in use for years, but on inanimate objects, not people!
As for the body searches being performed by Airport Security Screeners, read this take on them by a former Miss USA and then decide for yourself.
http://www.susiecastillo.net/blog/2011/4/25/my-tsa-pat-down-experience.html