What do I need to do to travel to the USA?

[Eldritch Warlord]

4) There is usually a line without x-ray scanners.
Unless you want cancer because shooting radiation at tens of thousands of people a day is legal in America for some reason, try to go in that one (it will involve a physical search though). Even if you're in an xray line, you can request a body search instead. It's up to her, really.

Why America adopted the type of body scanner that emits harmful ionizing radiation instead of, you know, the one that doesn't that works just as well is a pretty good question that we'll never have an answer for.

I don't know why the legality should change based on the number of people subjected to a scanner. Regardless the rad dosage from a backscatter x-ray is roughly equal to a few minutes of high altitude flight so I wouldn't be concerned.

Furthermore not even every airport uses full body scanners.