In cases like this I am sure there would be no Halachic ruling banning it. Just the way a woman is allowed to sit next to a man who is not her husband on a bus or plane despite how some haredi feel something like this I am sure would also be acceptable. This is about protection of life and nobody is interested in the woman herself all they care about is she has no bombs or weapons.. She is not looked at in a sexual way. Also as a lest resort for those orthodox who go to extremes then they can have a female security officer give the woman a physical search behind a screen. This is a small group or rabbis who have heard about a new technology they don't understand the first thing about and they are jumping to conclusions without first learning all the facts about the thing.
Iran deal opposition grows among U.S. Republicans, Reuters poll shows (Reuters)
from the article: European rabbis call new airports scanners 'immodest'