WASHINGTON - November 2, 2010 - Having been taught by nuns in grade school and later going through military boot camp, I have always disliked uniformed authorities shouting at me. So I was unhappy last week when some security screeners at O’Hare International Airport in Chicago started yelling.

“Opt out! We got an opt out!” one bellowed about me in a tone that people in my desert neighborhood in Tucson usually reserve for declaring, “Rattlesnake!”

Other screeners took up the “Opt out!” shout. I was marched from the metal detector lane to one of those nearby whole-body imagers, ordered to take everything out of my pockets, remove my belt and hold my possessions up high. Then I was required to stand still while I received a rough pat down by a man whose résumé, I suspected, included experience at a state prison.

“Hold your pants up!” he ordered me.

What did I do to deserve this? Well, as I approached the checkpoints, I had two choices. One was a familiar lane with the metal detector, so I put my bag on that. To my right was a separate lane dominated with what the Transportation Security Administration initially called “whole-body imagers” but has now labeled “advanced imaging technology” units. Critics, of course, call them strip-search machines.

I don’t like these things, and not just because of privacy concerns or because of what some critics have asserted are radiation safety issues with some of the machines that use X-ray technology.

I don’t like the fact that I have to remove every item from every pocket, including my wallet and things as trivial as a Kleenex. You then strike a pose inside with your hands submissively held above your head, like some desperado cornered by the sheriff in a Western movie, while the see-through-clothes machine makes an image of your body.

The TSA’s position is that anyone can “opt out” of a body scan for reasons of privacy or whatever, but will then be subjected to a thorough physical pat down and careful search of belongings.

In my case, I had been routinely using a normal metal detector checkpoint, when I was ordered to switch lanes and instead go to one of the new machines. I said I would prefer not to, given that my carry-on bag, laptop and shoes were already trundling along the regular machine’s conveyor belt out of sight. That’s when the shouting started.

As of Monday afternoon, the agency had not responded to several requests for comment on this. Last week, the agency did tell me that there were 317 of the advanced imaging technology machines now in use at 65 airports around the country.

About 500 should be online by the end of the year, the agency said, and another 500 are expected to be installed next year. Ultimately, the agency plans to have the new machines replace metal detectors at all of the roughly 2,000 airport checkpoints.