The amount of radiation from the scanner is far less than the amount of radiation you receive from dental x-rays, a mammogram or the actual flight itself. Scanner dose is approximately 1.46 microrems, dental x-ray 15 millirems, mammogram 70 millirems, round-trip flight from New York to LA 3 millirems. In order to get enough radiation from the scanner to reach the maximum "safe" annual limit listed by ANSI you would have to walk through the scanner 47 times per day, every day of the year

I'm a fairly frequent flier, I always wear an underwire bra and I almost always end up in the scanner - and that's fine with me. My bra has never set it off - but a metal clip in my hair, the fold of my jeans over my sock at the ankle and the crotch of my pants being too baggy has resulted in the additional pat down - which consisted of a quick pat down of the area in question.

If you are really that concerned about it you could take some supplemental iodine. But you probably get exposed to more radiation in your every day life than that 10 seconds in the scanner a few times per year combined.

They say they are safe, but ever since I was full body scanned the first time (when they first were introduced) I've developed some funny skin marks:

First is a mark on the pad my pinky finger... it appeared and has been growing. it's now the size of a .25 carat diamond, and all my doc says is "let's keep monitoring it"... LOL. Until when, it covers my finger tip? It's not a mole, it's under the skin, and I swear it throbs each time I've been scanned since.

Second mark: on my forehead near the hairline. same deal... started off as a dark mark the size of a pin-pick and has grown so that it can be easily seen.

As a woman, I don't like the pat downs... and often when offered this as an alternative, there is an underlying "We're going to do a VERY thorough search if you don't acquiesce and get scanned"... so in the past 2 years I was scanned 10 times at least. (Yikes. I had not counted before...)

I know this is stupid and have started opting out more. I no longer have to travel for business as frequently and choose to take the train or other land transport when convenient... (and sometimes when not. But a 28 hour train ride over a weekend beats a 4 hr wait at the airport, scanning, and horrible flight in my books!)

I'm rambling to say "better safe than sorry. Opt out. I wish I had never subjected myself to the scanners."

Last time I flew out of Seattle, they didn't have the scanners running. The underwire in my brand-new bra set off the metal detector, so I had to go for the full TSA gropedown--or not fly at all. Three other people were getting patted down at the same time I was, and they were all women--because apparently bras are such a goddamned threat.

I don't like being touched by people I don't know well. It's not related to any trauma or abuse; I've always been that way. That's why I color my own hair, go far too long between dental checkups, avoid doctors like the plague, and take the long way around when I see one of those people with a "Free Hugs" sign.

So while I stood there and tolerated TSA's intrusion into my personal space, I also resolved to buy a bra without underwires when I got to my destination. It didn't even have to make my boobs look good; it just had to keep me from being fondled in public again.

My personal choice? I'll take the scanner. I don't fly that often--maybe 6-10 US/Canada flights per year. I don't believe the amount of radiation I am exposed to during one scan is going to do me any significant harm--I'd probably be exposed to more radiation on a flight to Sydney, or while receiving medical x-rays.