If the scan gives you the radiation of one xray, and the RT gives you the radiation of 500,000 xrays (I'm not checking the validity of those statements), then you will get either 2 or 4 extra against 500,000. (You might change planes and have an extra).
In my mind the choice to do the 500,000 makes the 2 absurdly irrelevant for a normal holiday traveler - if you did it every day, the question is very different. Cutting out two is a nice "less radiation" banner to wave, but is it significant? I do not think so.
The real question should be the level of the search. I fear that the pads seen in the scan will trigger the pat down, which will then delay everything while I am turned inside out and have explain the pads in a most public place. But, while all this is going on, your personal stuff, bag, watch, wallet, etc., is in a box on the belt where anyone can just pick it up and keep walking. That has happened to me multiple times, even just walking through the detector.