This had some good information that I either didn't know or hadn't taken on board my aging brain, especially the information about service calls.

"John Sedat, emeritus professor of biochemistry and biophysics at the University of California, San Francisco, believes that the effective dose could be 45 times as high as the T.S.A. has estimated, equivalent to about 10 percent of a single chest X-ray."

"The machines, though, have had mechanical problems. A recent T.S.A. report said that between May 2010 and May 2011, there were 3,778 service calls concerning mechanical problems in backscatter X-ray machines. Radiation safety surveys were conducted after only 2 percent of the calls."

http://well.blogs.nytimes.com/2012/0...ering-worries/

TSA doesn't care if the Backscatter Strip Search Machines are safe. TSA is nearly impossible to hold accountable so a few hundred or thousand cases of cancer won't bother TSA's leader, John S. Pistole.

Makes me happy to fly out of a commuter airport that still uses a metal detector.

I was talking with a radiologist about this. We're talking about a radiologist (MD from Dartmouth), and a man of some distinction. He always opts out. Just as I say as a chronic disease epidemiologist, "there is no safe level of radiation, and it is cumulative."

The radiologist said, "There is going to be a big price to pay for these machines." We both agree that it's likely to be an increased cancer incidence among TSA employees, who are not monitored for radiation exposure. Just like police who got cancer from radar guns, the machine that "keeps us safe" also makes us sick.

ProPublica's investigation had the most solid answer: there are two options (MMW and backscatter) so why would you ever pick the riskier of the two?

The other argument is that the machines don't work. The resolution pat-downs, high-profile cases of smuggled items, etc. And contrary to the TSA's claims, they're not quicker. Compared with a metal detector, scanning equipment slows TSA lines, creates a backlog of passengers, and a much easier target for an attack.

I'm starting to think that the TSA's union might start demanding precautions for employees, who wear no lead protection nor dosimeters.

I don't like the MMW machines, but I usually just grit my teeth and deal with it if I can't self-direct a metal detector. But at many airports: Seattle, Boston, O'Hare, JFK, there are no MMW machines in many terminals: just backscatter. Boston is supposedly switching, and I hope the others follow suit.

In defense of TSA, there is some 'truth' to its claim that the NoS is faster than the 'other' process: when the NoS is the primary search (contrary to Nappy's assurances), it is indeed generally faster than the alternative full-body grope, particularly since TSA frequently deliberately lengthens the process by making the pax wait for an available 'assist' and by adding a gratuitous swab and test.

If you mean "switching to the landfill", I'd be with you.

But otherwise it's okay if countless more millions are spent on another model, that are still slow, that can still be circumvented and that still have an alarmingly high false positive rate?

When the agency that claims a process is faster also gets to set the speed of any alternative processes, there's not much value to any such speed claims.

Their union, like most unions, is a joke. I'm sure they're good a collecting dues, but not much else. The union has failed its members on dosimeters, failed the members on other radiation testing and really is only half way decent at fighting TSA on uniform management directive violations. So unless the TSO attached a dosimeter to their Mexican manufactured shirts on their own, don't expect the union to do much of anything.

We've heard on many occasions that TSOs are actually prohibited from wearing dosimeters on their uniforms.

I wonder, however, if a dosimeter is effective if carried inside a shirt or pant pocket?

I'm not a physicist, but I think that it wouldn't matter. We're talking about high energy radiation - not "large" alpha particles - so if you're close enough, the x-rays can easily penetrate a relatively flimsy layer of clothing and the dose wouldn't materially be affected.

And think about it - if you go to the dentist and get x-rays, they don't just cover you with piece of fabric, they cover you with a heavy dense lead shield. If clothing inhibited it enough, that wouldn't be necessary.

If your shirt or pant pocket was enough to stop it then they couldn't see through the clothes.

I just ran across a brief article referencing the NYT piece here.

Sure, clothing doesn't entirely block the radiation, but I wonder if being in a pocket would affect the accuracy of a dosimeter. Physical contact with the cloth, or differences in moisture or temperature - do any of those factors alter the effectiveness of a dosimeter badge? I just don't know enough about the devices themselves to know for sure.

http://www.ehow.co.uk/how-does_53158...eter-work.html

I've been wondering how long is it going to take California to mandate a placard that reads "WARNING: This machine emits radiation known to the State of California to cause cancer and / or other reproductive harm".


I'm wondering of the TSOs not wearing lead jackets is something done to a) cut costs, b) not scare passengers. Personally I've never been given a lead vest for small dental x-rays (those little 1"x1" squares), but I was given one once for a panoramic dental x-ray. That was the only time I saw the tech wearing one, coincidentally, the machine looked like it was surplus equipment from the USSR. So if they start wearing lead vests people will start freaking out because that would be something against the assurances of Mr. Pistol that the radiation is small.