And the author says the dose is really 14.76 microrem, but doesn't dispute the equivalence to flight time. So really it's equivalent to 3 minutes of flight, not just 2.

50% of trivial is still trivial.

Oh, and the author says that the margin of error on these measurements is large. So perhaps the TSA didn't lie at all, they just measured 10 microrem. Even if the margin of error is 1000% the result is still trivial.

So... basically this is non-news about a technology which isn't even in use anymore. The TSA now uses millimeter wave technology as the author is aware ("these backscatter x-rays are decommissioned and sitting in a warehouse").

There are a lot of good reasons to be concerned about the TSA's use of imaging technology. This is not one of them.

"While these scientists still conclude that this is a low dose of radiation, it shows that, if correct, we were lied to, again, and anyone who walked through those scanners was given nearly 50% more radiation than they signed up for."

The point is not that 14µrem is dangerous to an individual on occasion, it's that the government irradiated us at a rate different than what they promised.

It will also have societal effects. I've seen calculations that estimate that something like 6 people will die from cancer as a result of the radiation from 700M TSA screenings given per year. That estimate should now be adjusted, and we should again say, "How many lives does the TSA save that justifies this?"

Lets take the case of water toxicity, if you're a little dehydrated and you drink 5 litres of water in one sitting you'll die. However, if you drink a few litres of water everyday over the entire day you'll have no issue.

It's 10 vs 14. Neither is significant, neither matters. All measurements have errors, if a source is claiming otherwise you best assume they are not educated very well on science - and have not done a good job communicating with the scientists making the measurements. So as far as anybody is concerned, the difference between 10 and 14 is so insignificant it may as well be less than 10.

Their point is that the 'overall' dose is, not only unknown, but measured in a non-meaningful way. "Garbage-in, Garbage out." A full body scan produces 10 microrem of emission, concentrated to the first few microns of skin - (which happen to be where gonads, breast tissue, skin & eyes are...). This is very much unlike riding in an airplane where the exposure is truly whole-body. The "expose per cell" in these two cases is wildly different.

[1] http://www.npr.org/assets/news/2010/05/17/concern.pdf

Cancer very much is a stochastic event, and so probabilities are all we can talk about. But reducing the number of encountered objects by billions-fold while keeping the rate of exposure the same can wildly skew data that you had relied upon to determine a 'safe' dose.

Considering how oblivious some companies are to the difference between $0.02 and 0.02 cents, milli and micro might be way beyond the ability of some TSA technicians to understand.

Of course these new machines cannot fail the exact same way as the Therac 25. But could they fail in a new, unpredicted way? I dunno. I am not familiar enough with how the backscatter machines are implemented to be able to predict how they could fail. But I maintain neither are most of the people who defend these machines as safe.

http://usatoday30.usatoday.com/yourlife/health/healthcare/go...

I think "nobody would notice" is a pretty accurate description of what would happen in that case.

Researchers have pointed out that international pilots and stewardesses may already receive more cosmic radiation than may be safe due to high altitudes and long duration. This is why they're allowed to skip the scan. Why shouldn't frequent international business travelers receive the same treatment?

Also, all machines have a percentage of possibility of breaking down or misbehaving. Do we want to subject someone to the possibility of being irradiated by a damaged scanner when the odds are greater than harm from terrorism?

That said, I don't like it that TSA staff don't wear radiation badges, at least I haven't noticed any. One lady working for TSA, at the backscatter device, was very pregnant and I wondered about the radiation hazard for her, if any.

Q: Why aren’t your officers permitted to wear dosimeters?

A: There is a really good reason for this. The emissions from our X-ray technology are well below the requirements that would require their routine usage. To help reassure passengers and employees that the technology is safe, however, health physicists with the U.S. Army have been conducting area dosimeter surveys at multiple airports nationwide.

Sounds like nonsense to me... at the least, I'd like to see the resulting data from those surveys posted online and kept up to date so the public can see it.

The funny thing is most of the fear stems from TSA style non-sense that has people freaked out about radiation. Everyone worries about dirty bombs, and TSA x-rays, fukushima, no one about the thorium / uranium released from burning coal.

In fact, on occasion I've had them insist on me keeping my belongings outside the scanner. I wonder if it's a liability for them to have them back there where I can't monitor them. After all, the screenings are always conducted with your luggage in eyesight.

Regardless, I always opt out too.

They are.

- Inflammatory headline irrelevant to content ("Nude" Body Scanners)

- 50% more than an insignificant amount of radiation is still insignificant, and likely difficult to measure precisely. The idea that the TSA would "lie" about this is silly.

- I'm not a fan of the TSA, however inflammatory articles are not what I look for on HN.

I've flown every month this year, sometimes multiple times. I opt out every single time.

More irritating is the randomness of metal detectors vs. scanners. It's the luck of the draw.

The x-ray versions are gone (and with them any small chance of dangerous radiation exposure). And I'm told that they no longer show your naked body to agents, but rather a generic outline that labels potential objects of concern. So the things about them that I've felt had the potential for a direct negative impact on me personally are mostly in the past.

Because of that, the last time I flew, it struck me that opting out was purely a political protest, and that the only effect it was likely to have was to make things flow a little bit less smoothly for all the other poor folks standing in the long line behind me. I just didn't see the payoff anymore. So for the first time, I went through the blasted machine. They did a quick patdown anyway, but I guess that's par for the course.

I wish I knew a way to take an effective stand against this system. But I've ceased to believe that opting out is it.

Ok, probably not, but still ...

Why should it have this effect? When I opt out, they have me stand in a little area off to the side until a scanner is ready for me. I don't hold up the line, and, as far as I know, most people don't even notice that anything is happening (except that some wonder curiously why I am electing to stand around, apparently for recreation, without belt or shoes).

And then you get to watch the employees' form of protest as they chit chat for a few minutes before heading over to fetch you.

i read somewhere that if we were serious about security, we'd be better off hiring a couple dozen sniffer dogs per airport and letting people walk right through, but the tsa looks to me more like a national jobs program than a security force (which is fine if it didn't make travel such a hassle).

I agree with your main point, and am sorry to nit-pick, but I think that it's important: how you feel doesn't, and shouldn't, have any effect on the policy. In fact, the whole phrase 'security theatre' describes precisely the phenomenon of making (easily mollified) people feel secure instead of being secure. I am not at all saying that you are in this boat (it sounds like you're not), only that I think the word choice is very important.

It bothers me to play on fears about radiation and sexual paranoia to get people to see that government interests diverge from theirs, and that perhaps maybe there is something wrong about eg deploying these ridiculous scanners.

But whenever I try the ideological approach, people resist applying abstract concepts to judge the concrete situation. Either they have little experience doing so, or the more erudite have merely used their intelligence to internalize all the flimsy justifications that, by common law, have destroyed any basis of this government's original charter.

I guess the analog of my initial observation applies to rule by the masses (with respect to rationalism) as well so, at least for this topic, hysteria it is.

http://rt.com/usa/154672-tsa-breast-milk-settlement/

But she did get a settlement and so -if you have the time and know your rigts and can keep calm[1]- it might be a good idea to opt out.

[1] calm because otherwise tasers or guns.

[Edit -- Comment above, now deleted, suggested that using "nude" in the title will result in fewer hits because of Web filters.]