Hacker News Reader

Comment by mmcconnell1618 | Hacker News Reader

Keep in mind that there are 2 types of machines in common use. 1) Backscatter (X-Ray) and 2) Millimeter Wave (Radio) and they operate very differently.

Based on what I've read I'm comfortable with the millimeter wave system and have some concerns about the backscatter x-ray system. However, if the backscatter system operates correctly then the amount of radiation exposure is really quite small compared to the amount you'd receive on the actual flight. I still think I'd opt-out of the backscatter system until long term effects and performance are studied.

Tip: Millimeter wave looks like a circular telephone booth, Backscatter x-ray looks like a big rectangular wall you stand in front of.

http://www.jaunted.com/story/2010/1/5/163631/3181/travel/Ful...

View on HN

> The amount of radiation exposure is really quite small compared to the amount you'd receive on the actual flight.

One difference. I get something back from the flight. I get to be in another place rather fast. I am willing to take a small radiation dose for it. I am not getting anything back from being scanned by a Rapiscan (that is the name of the company that makes most of them).

That's horrible logic. To carry it to absurdity: the flight gets you from A to B rather quickly - why all the delays while they, you know, put fuel and peanuts into the plane? They should just do away with that, it's not the flight, all you need is the flight.

Similarly: buy 1 get 1 free? Why not just give out the free one?

As absurd as the security theater is, it's part of the packaged deal that includes "the flight". The radiation from the machines may not be part of the physical act of moving you from A to B, but that doesn't mean they can just be removed.

These machines don't provide any increased security over a pat down. It might be convent for the TSA but harms the passengers.

And given the number of test firearms that the TSA manages to get through the carry-on X-ray, it'd hardly be reassuring even if the full-body X-ray turned out to be useful.

Completely agree. But that's a different issue entirely - arguing that it's useless because it's not part of the flight is complete nonsense.

You still don't make any sense. Here is activity A: flying. Here is activity B: walking through a Rapiscan machine.

One can do activity A & B independently. One can board a plan and fly ( I just did recently, got into a line that didn't have an x-ray machine and flew). Or one can do B -- keep buying tickets and go through security without flying and just do that all day.

Now the argument was both activities will blast you with x-rays so at least "logically it doesn't make sense to complain about one but not the other". My comment was that it is not the same, there is a difference. I am willing to engage in activity A because that gets me from one place to another faster. I am not willing to engage in activity B because I get nothing for it. You said it yourself it is security theater, so I get nothing but harm from it. Therefore it the two activities are not the same.

> The radiation from the machines may not be part of the physical act of moving you from A to B, but that doesn't mean they can just be removed.

I am confused since to you it seems that having the ability to fly without being blasted by x-rays and be seen naked by some underpaid TSA guy is such an outlandish thing.

Are you a teenager? Do you remember flying before 9/11? Do you remember how we had daily airport bombings and hijackings? (Yeah, neither do I). Then do you remember how many terrorists TSA caught red-handed, just about to board on the plane with an explosive device in all these years? I do - 0.

Then you acknowledge it is security theater but somehow claim that we need it. Sorry but that doesn't make any sense.

However, if the backscatter system operates correctly then the amount of radiation exposure is really quite small compared to the amount you'd receive on the actual flight.

The most compelling argument I've heard about the dangers is that while the total amount of ionizing radiation you receive is small compared to the flight itself, the radiation is chosen such that it doesn't pass through you and more of it is absorbed at the skin.

Even if they are safe, I will probably opt-out but I definitely don't like being separated from my baggage on the belt during the pat-down process.

In my experience (I've opted-out 6 times now in the past 1.5 years), they let you take your baggage with you to the pat down area, and you never have to lose eye contact.

I've done it a few times now, and they have always had me identify my bag, shoes, etc on the belt before the pat down. Then they set the bags aside. They also insist that you don't touch it until you are finished with the patdown.

This is not always true.

I was at JFK Terminal 1 (International) and I got separated from my bags on the belt for an extended period of time. When I complained that my bags were at risk of being stolen or lost, the TSA agent said "You opted out. That's what happens."

Needless to say, I found a supervisor and complained. I'm also filing an official complaint. I have no problem being patted-down but I do have a problem with them trying to coerce me to do something I've expressly asked to be excluded from, and using my fear of property loss to get me to do it. That's WRONG.

Even if they are safe, I will probably opt-out but I definitely don't like being separated from my baggage on the belt during the pat-down process.

This usually isn't an issue, you can see your bags or have them set aside. The issue I have personally been running intro (I travel about 2x per month on average, meaning potentially 4 trips through these things) is that when you opt-out it seems like it is taking longer and longer for them to find a suitable pat-down attendant.

This could just be my own skepticism, but it certainly seems that the wait is getting longer and longer each time.

The power of ionizing radiation being absorbed entirely at the skin (not the entire body mass) is also my concern. Those figures of the radiation being equal to "just a few minutes of flying in the plane" are totally inaccurate.

I am also notably concerned about that ionizing radiation being absorbed by my open eyes and also down below.. not to be crude.

you are absolutely right. Talking about small exposure only is a typical marketing trick. The type/frequency of the radiation and absorbing site would make all the difference. They just abuse the general ignorance of the population. When i'm to fly, i'm all for groping. Just need to get a Prince Albert done.

http://www.deadseriousnews.com/?p=573

http://thewashingtonfancy.com/2011/09/18/man-takes-viagra-we...

"A TSA spokesperson declined to comment on this specific case, but said that anyone ejaculating during a pat-down would be subject to arrest."

> The most compelling argument I've heard about the dangers is that while the total amount of ionizing radiation you receive is small compared to the flight itself, the radiation is chosen such that it doesn't pass through you and more of it is absorbed at the skin.

I have a genetic pre-disposition to skin cancer. The total radiation dose may be small, but the type of radiation (ionizing), and the fact that it is targeted at, and fully absorbed by the skin doesn't give me comfort. Should I be concerned?

That's a rhetorical question, because in reality we just don't know because no one has studied it. And that's scary. I've opted out ever since these things were introduced, and will continue to do so.

if the backscatter system operates correctly

That's putting a lot of faith into the TSA.

Even leaving aside whether the TSA is well-run or not, the lack (as far as seems to be publicly known) of a rigorous risk analysis is a bit troubling. Not just as far as the medical questions go (e.g. what's a safe exposure level), but just standard engineering stuff.

For example, since backscatter machines work by scanning a narrow beam very quickly over the body, a particularly problematic failure mode would be the beam remaining energized but failing to move, which would give a very high localized dose. Even if that "can't happen", you would typically have some sort of failsafe that should rapidly cut off the beam in that case. If this were a medical device, there are fairly well established ways of doing failure-mode analysis to quantify that risk and the reliability/speed of the failsafes. Have companies like Rapiscan done that?

There is a huge difference in the dose even from properly certified medical X-rays, depending on how old the machine is, the maintenance, the settings and the method selected http://www.theglobeandmail.com/life/health/ct-scan-radiation...

What makes you comfortable with the mm wave system? My understanding is that more research is needed on how millimeter waves affect cells. http://thz.caltech.edu/

While more study is needed with any system it is my understanding that millimeter wave radio waves will not penetrate very far beyond the surface cells while x-rays will pass through the entire body mass. Just on the raw mass affected by the device the millimeter wave system seems less risky.

The x-rays don't pass through the entire body. They go only into the skin. That's actually what's most concerning about them. Because they don't pass through the body, they are concentrated entirely in one layer which receives a much higher dose.

http://www.technologyreview.com/blog/arxiv/24331/

Having a tendency to shred DNA is not what I would consider safe at all.

Yes, EU only banned X-Ray scanners. As for the other technologies of full body scanning, well, these are actually green lighted, not banned: http://www.dw-world.de/dw/article/0,,15532933,00.html

>amount of radiation exposure is really quite small compared to the amount you'd receive on the actual flight

Yes, I believe that's true however we should also consider the health of the TSA workers who are subject to constant exposure for 8 hours a day. For all that we can say, it's their choice to work there, that's not a fair assessment given today's job climate.

> The amount of radiation exposure is really quite small compared to the amount you'd receive on the actual flight.

Except that you get it in a milliseconds, instead of over a period of several hours. I get a lot of sunshine in a day (haha who am i kidding i'm a programmer, but humor me), but ask an ant what its like to get the equivalent energy in a few seconds.

However, if the backscatter system operates correctly then the amount of radiation exposure is really quite small compared to the amount you'd receive on the actual flight.

Very true, but the danger from it is still about the same tiny magnitude as the danger from terrorists without the x-ray system.

But the tiny danger from terrorists is unaffected by the machines so we have that anyway. The machine is just extra risk for no gain.

I wouldn't say entirely uneffected, but I do think the reduction is very small. The point is, though, that even if we were to assume the machines were 100% effective the end result would be to be spending money to not make anyone any safer.

Reply on news.ycombinator.com