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Leading scientists say backscatter X-ray may be far more dangerous than thought

npr.org

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Re: Leading scientists say backscatter X-ray may be far more dangerous than thought

#11

Post by aperiodic »

pygy_ wrote: post #3
sstone wrote: post #2

The document was linked here before but is very detailed and interesting, even naming specific issues: A) The large population of older travelers, >65 years of age, is particularly at risk from the mutagenic effects of the X-rays based on the known biology of melanocyte aging. B) A fraction of the female population is especially sensitive to mutagenesis provoking radiation leading to breast cancer. Notably, because t…

I've been told by an engineer friend of mine that the radiation dose these scanners deliver was dwarfed by the in-flight cosmic irradiation. He didn't give me numbers, though. It would be nice if a radiotherapist (or another expert) could chime in on this topic. ---------------------------- edit: answering my own question: he's wrong. from [1] : >The estimated occupational effective dose for the aircraft crew (A 320)…

The health risks can't just be quantified by the overall radiation dose. It depends on how that dose is deposited in the subject. The letter raises the concern that the since almost all the radiation is absorbed by the skin, the dose to your first centimeter or two of epidermal tissue may be fairly high. If the calculations that concluded the devices were safe assumed that the radiation was evenly distributed throughout the body, then the safety of the devices could be suspect.

Re: Leading scientists say backscatter X-ray may be far more dangerous than thought

#12

Post by AngryParsley »

eiji wrote: post #7
AngryParsley wrote: post #4

That letter is from April. The FDA wrote a response last month: http://www.fda.gov/Radiation-EmittingProducts/RadiationEmitt... The recommended limit for annual dose to the skin for the general public is 50,000 µSv. The dose to the skin from one screening would be approximately 0.56 µSv when the effective dose for that same screening would be 0.25 µSv. Therefore the dose to skin for the example screening is at least…

"Most" of the concerns ... ... are "likely" safe. It's a tiny line between FUD and alertness. I prefer people bring this stuff up every now and then to remind all of us to never stop questioning things.

It's so easy to get caught up in the halo/horn effect and try to make every fact about backscatter machines bad. But the truth is complicated. It requires weighing all evidence, not just looking at evidence that agrees with your current views.

89,000 times lower than the annual limit.

I'm not a fan of the TSA or backscatter machines, but facts are not up for debate. If backscatter machines cause cancer, it would be very surprising and it would tell us something new about physics and/or biology.

Also, if you worried about every risk that was as low as backscatter machines, you simply wouldn't be able to function in society. 5 minutes in a car is a 1 in 5 million chance of death.

Re: Leading scientists say backscatter X-ray may be far more dangerous than thought

#13

Post by forgottenpaswrd »

usinglogin wrote: post #10
tomjen3 wrote: post #8

Earlier quoted context omitted.

It does not matter if they are safe (which they aren't), it matters that they be removed. A little fud now and then is a good thing.

Hitler: "It does not matter if the jews are good citizens (which they aren't), it matters that they be blamed for all our problems. A little fud now and then is a good thing."

Godwin Law, you loose the argument!!

http://en.wikipedia.org/wiki/Godwin%27s_law

Re: Leading scientists say backscatter X-ray may be far more dangerous than thought

#14

Post by fluidcruft »

pygy_ wrote: post #3
sstone wrote: post #2

The document was linked here before but is very detailed and interesting, even naming specific issues: A) The large population of older travelers, >65 years of age, is particularly at risk from the mutagenic effects of the X-rays based on the known biology of melanocyte aging. B) A fraction of the female population is especially sensitive to mutagenesis provoking radiation leading to breast cancer. Notably, because t…

I've been told by an engineer friend of mine that the radiation dose these scanners deliver was dwarfed by the in-flight cosmic irradiation. He didn't give me numbers, though. It would be nice if a radiotherapist (or another expert) could chime in on this topic. ---------------------------- edit: answering my own question: he's wrong. from [1] : >The estimated occupational effective dose for the aircraft crew (A 320)…

The PR video/slideshow at the last checkpoint I went through said that the dose was safe because it was equivalent to being in the airplane for 3 hours. This presumably was meant to be comforting, but in my mind I was computing a 3hours:3sec ratio and trying to remember if time-dose averaging was appropriate (I work in MR, and it's been a while since my ionizing radiation course). I was not asked to go through the machine, but I would have refused simply because of the flippant tone of the 3hrs in the air claim.

Re: Leading scientists say backscatter X-ray may be far more dangerous than thought

#15

Post by mortenjorck »

AngryParsley wrote: post #12
eiji wrote: post #7

Earlier quoted context omitted.

"Most" of the concerns ... ... are "likely" safe. It's a tiny line between FUD and alertness. I prefer people bring this stuff up every now and then to remind all of us to never stop questioning things.

It's so easy to get caught up in the halo/horn effect and try to make every fact about backscatter machines bad. But the truth is complicated. It requires weighing all evidence, not just looking at evidence that agrees with your current views. 89,000 times lower than the annual limit. I'm not a fan of the TSA or backscatter machines, but facts are not up for debate. If backscatter machines cause cancer, it would be v…

I think most would rather the use of these devices be banned on principles of their invasiveness rather than on safety concerns. Otherwise, you just get a "safer" version of the same thing in a few years.

Re: Leading scientists say backscatter X-ray may be far more dangerous than thought

#16

Post by pygy_ »

aperiodic wrote: post #11
pygy_ wrote: post #3

Earlier quoted context omitted.

I've been told by an engineer friend of mine that the radiation dose these scanners deliver was dwarfed by the in-flight cosmic irradiation. He didn't give me numbers, though. It would be nice if a radiotherapist (or another expert) could chime in on this topic. ---------------------------- edit: answering my own question: he's wrong. from [1] : >The estimated occupational effective dose for the aircraft crew (A 320)…

The health risks can't just be quantified by the overall radiation dose. It depends on how that dose is deposited in the subject. The letter raises the concern that the since almost all the radiation is absorbed by the skin, the dose to your first centimeter or two of epidermal tissue may be fairly high. If the calculations that concluded the devices were safe assumed that the radiation was evenly distributed through…

Thanks for the details.

I could not find the energy of the X-Rays used for these scans, but they would likely be low-energy (high energy rays don't scatter much), hence absorbed mostly superficially, as you said.

Re: Leading scientists say backscatter X-ray may be far more dangerous than thought

#17

Post by chroma »

tomjen3 wrote: post #8
AngryParsley wrote: post #4

That letter is from April. The FDA wrote a response last month: http://www.fda.gov/Radiation-EmittingProducts/RadiationEmitt... The recommended limit for annual dose to the skin for the general public is 50,000 µSv. The dose to the skin from one screening would be approximately 0.56 µSv when the effective dose for that same screening would be 0.25 µSv. Therefore the dose to skin for the example screening is at least…

It does not matter if they are safe (which they aren't), it matters that they be removed. A little fud now and then is a good thing.

If you're willing to say anything to make the other side look bad, why should anyone give you credence?

Re: Leading scientists say backscatter X-ray may be far more dangerous than thought

#18

Post by tomjen3 »

chroma wrote: post #17
tomjen3 wrote: post #8

Earlier quoted context omitted.

It does not matter if they are safe (which they aren't), it matters that they be removed. A little fud now and then is a good thing.

If you're willing to say anything to make the other side look bad, why should anyone give you credence?

There is a big difference between a little fud and being willing to say anything. These machines have been called, by a reputable scientist, as potentially very dangerous. I see no problem making sure everybody knows that they are dangerous, nor do I particular care to present both sides of the argument.

Re: Leading scientists say backscatter X-ray may be far more dangerous than thought

#19

Post by tomjen3 »

usinglogin wrote: post #10
tomjen3 wrote: post #8

Earlier quoted context omitted.

It does not matter if they are safe (which they aren't), it matters that they be removed. A little fud now and then is a good thing.

Hitler: "It does not matter if the jews are good citizens (which they aren't), it matters that they be blamed for all our problems. A little fud now and then is a good thing."

When the machines become sentient, you may have a point.

In addition, the machines are bad on privacy terms, but since the debate has been frame such that those who advocate privacy are considered suspect, we have to work with what we have and make the best of it.

Re: Leading scientists say backscatter X-ray may be far more dangerous than thought

#20

Post by bluedanieru »

chroma wrote: post #17
tomjen3 wrote: post #8

Earlier quoted context omitted.

It does not matter if they are safe (which they aren't), it matters that they be removed. A little fud now and then is a good thing.

If you're willing to say anything to make the other side look bad, why should anyone give you credence?

Maybe they shouldn't, but when you're going up against the kind of ruthlessness that will stop at nothing to invade your privacy by any means, limiting your angles of attack for ethical concerns might not be palatable for everyone. I'd like these machines to be banned for privacy concerns as well, but if they're banned for safety concerns that I made up, that's still better than them being put in every airport.
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