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Chance of Dying From Backscatter Radiation Same as Chance of Terrorism

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Re: Chance of Dying From Backscatter Radiation Same as Chance of Terrorism

#61

Post by dotBen »

josefresco wrote: post #44
jerf wrote: post #43

So, the risk from a backscatter radiation machine is roughly equal to the risk from terrorism. The Federal Government, via the FDA, tells us that the risk of the backscatter machine is "minuscule". Therefore, in the Federal government's own risk terminology, the risk from terrorism is "miniscule". Why are we spending all this money on a "miniscule" threat? Why are sexually molesting the population over a "miniscule"…

Terrorism can in both small and very large ways effect entire nations. backscatter radiation? Not so much. It's illogical to compare the two and make judgments on based solely on the death rate. You don't need to kill people (all of them) to influence them.

I think the point JoseFresco is making, which is a little lost in his reply, is that an event like 9/11 in which 3000 people died had a much bigger impact upon America and the world than the 3000 people who died in on year of a particular form of cancer.

The prevention of terrorism is more than just the prevention of immediate deaths related to the incident itself.

Protecting civil liberties are crucial, and I'm not in anyway agreeing with what the TSA is doing. As a side point, it's worth remembering that terrorism is a world issue and if you look more internationally some Western Countries don't even enjoy the level of civil liberties and freedoms that America does even now.

In the UK you can't even refuse a Back-scatter scan and have a manual pat-down instead (which applies to US citizens returning home from a visit to London too, of course).

http://consumerist.com/2010/11/in-uk-if-you-opt-out-of-body-...

Re: Chance of Dying From Backscatter Radiation Same as Chance of Terrorism

#62

Post by butterfi »

yummyfajitas wrote: post #48
butterfi wrote: post #28

With all due respect to Dr. Reiz, and the Dept. of Physics at ASU, I think I'll be taking my advice from the group of doctors from UCSF (a school well known and respected for its medical research) who wrote a formal letter to the president's science advisor. The letter is worth reading. "Agard and several of his UCSF colleagues recently wrote a letter to John Holdren the president's science adviser, asking for a more…

I'll go with the physics prof. He did some calculations, admittedly imperfect, based on generally known principles of dosimetry, and got what seems like a reasonable order of magnitude result. All the MD's at UCSF said was "oh noes, the possibility of radiation danger isn't ruled out precisely by a previously done study, it might be dangerous." I'd be very curious to know whether they would use this same logic on a l…

Reasonable doesn't necessarily mean correct. In the face of specific questions raised by doctors with expertise in this specific field, is reasonable is good enough?

From the NPR article:

"The stated dose — about .02 microsieverts, a medical unit of radiation — is averaged over the whole body, members of the UCSF group said in interviews. But they maintain that if the dose is calculated as what gets deposited in the skin, the number would be higher, though how much higher is unclear."

The observation about how high a dose gets deposited is a very specific observation made by people who actively apply radiation to people on a daily basis.

Re: Chance of Dying From Backscatter Radiation Same as Chance of Terrorism

#63

Post by marze »

This discussion is properly focused at the core of the matter, the cost benefit analysis.

Some of the costs are easy to see, like the acute embarrassment some experience from an intimate "pat down" if they elect to avoid any risk from x-ray radiation.

Others are much more difficult, such as potential health consequences of the x-ray radiation exposure. Since the TSA has refused to disclose the x-ray flux, it is hard to even get started. The comparisons the TSA makes with other radiation sources are flawed because they assume the dose is uniform throughout your body when it is actually highest at the surface.

But even if an outside evaluator did have good numbers to start with, in the end the best you can expect are extrapolations using data from dramatically different radiation exposure, which is the nature of calculating radiation risks. The only way to have a non-extrapolated number is to expose half of a sample population to the scanner radiation and measure outcomes for 50 years.

Avoided consequences are easier to calculate. Of the 8,000,000,000 or so US domestic air travelers of the past ten years, zero have smuggled a bomb on board, and zero have attempted to. Zero out of billions of passengers.

The worst consequences are the loss of an aircraft. A terrorist cannot take control of an aircraft using a bomb, only destroy it. An X-ray scanner will not stop someone from bringing a knife onboard (even if it could, it is probably not possible to take control of an aircraft with a knife due to cockpit doors, passenger awareness, etc.)

So, cost benefit sum-up: zero attempts to smuggle bomb onto domestic flight over past 10 years, unknown but likely low health risk, consequences limited to loss of one aircraft due to screening failure.

Re: Chance of Dying From Backscatter Radiation Same as Chance of Terrorism

#64

Post by [deleted] »

nickpinkston wrote: post #47
josefresco wrote: post #44

Earlier quoted context omitted.

Terrorism can in both small and very large ways effect entire nations. backscatter radiation? Not so much. It's illogical to compare the two and make judgments on based solely on the death rate. You don't need to kill people (all of them) to influence them.

Isn't this the same utilitarian argument that would restrict all of diets for the sake of healthy, roads for the sake of safety, and civil rights for the sake of efficiency?

[deleted]

Re: Chance of Dying From Backscatter Radiation Same as Chance of Terrorism

#65

Post by fluidcruft »

marze wrote: post #63

This discussion is properly focused at the core of the matter, the cost benefit analysis. Some of the costs are easy to see, like the acute embarrassment some experience from an intimate "pat down" if they elect to avoid any risk from x-ray radiation. Others are much more difficult, such as potential health consequences of the x-ray radiation exposure. Since the TSA has refused to disclose the x-ray flux, it is hard…

> Of the 100,000,000,000 or so US domestic air travelers of the past ten years, zero have smuggled a bomb on board, and zero have attempted to.

At least two have succeeded in smuggling a bomb on board, but failed to detonate them. Look up the "Christmas bomber" and the "shoe bomber".

Re: Chance of Dying From Backscatter Radiation Same as Chance of Terrorism

#66

Post by aphyr »

Confusion wrote: post #52
aphyr wrote: post #38

Earlier quoted context omitted.

We know that short-term small doses of X rays results in increased probability of developing skin cancer. We know that prolonged exposure to low-level radiation sources increases your probability of developing skin cancer. We know that acute high doses of ionizing radiation leads to your skin falling off. Skin cancers are abnormally elevated in radiologists, survivors of Hiroshima who experienced even relatively low…

We know that short-term small doses of X rays results in increased probability of developing skin cancer. An increase that is so minute that we don't mind the dentist or doctor X-raying us. An increase that is so minute that we would accept it, if it actually reduced our chances of dying due to a terrorist attack. The radiation is not the problem: it is the intended goal that we have no reason to believe in. We know…

Preface: I totally agree with your argument that risks must be weighed against outcomes. I also believe that even if the scanning technology were totally safe, it would be objectionable on privacy grounds. I think we're going about the whole problem of security backwards. :)

An increase that is so minute that we don't mind the dentist or doctor X-raying us.

Actually, we do. There are good reasons we impose strict limits on your medical X-ray exposure annually, and why you wear a lead vest or use collars to protect other tissue. There's also a good reason the radiologist stands outside the other room to press the button. Two x-rays a year is not significantly mutagenic. Fifty? Then you start getting nervous.

Not WiFi or the low-energy spectrum of the sun. What energy is 'low' in this respect?. And how long is 'prolonged exposure'

UV exposure from solar radiation is one of the biggest melanoma risks. A few orders of magnitude up the frequency scale, X rays for far shorter durations also have mutagenic effects on skin tissue. It's possible that low-energy X rays, falling in the middle of that energy range, also cause cancer. We don't know for sure yet because we don't regularly expose people to them.

(I should mention that just because the X rays are low energy does not mean their effects scale linearly. Medical X rays are well above the Compton shoulder. IIRC (not enough time to check now) they're thermalizing slowly in heavy tissues as opposed to bouncing inelastically off the surface layers. Depending on the scattering cross-section for those energies, the backscattered X rays could be more ionizing. Total conjecture... I haven't done this for a while.)

Again, the problem is a slightly increased risk. But why is that increased risk a problem in the first place?

You're absolutely right. We have no good characterization of the risk. Radiation biometrics is fucking hard. I only want to argue that our current risk statement is inaccurate and poorly understood (for instance, we don't even know the angular flux of these machines), and offer some potential reasons why the risk might be higher than currently stated.

Re: Chance of Dying From Backscatter Radiation Same as Chance of Terrorism

#67

Post by _delirium »

yummyfajitas wrote: post #48
butterfi wrote: post #28

With all due respect to Dr. Reiz, and the Dept. of Physics at ASU, I think I'll be taking my advice from the group of doctors from UCSF (a school well known and respected for its medical research) who wrote a formal letter to the president's science advisor. The letter is worth reading. "Agard and several of his UCSF colleagues recently wrote a letter to John Holdren the president's science adviser, asking for a more…

I'll go with the physics prof. He did some calculations, admittedly imperfect, based on generally known principles of dosimetry, and got what seems like a reasonable order of magnitude result. All the MD's at UCSF said was "oh noes, the possibility of radiation danger isn't ruled out precisely by a previously done study, it might be dangerous." I'd be very curious to know whether they would use this same logic on a l…

Even on non-politically-charged topics, that is pretty much the standard operating practice, at least in the more science-oriented parts of medicine. If you want to know, "is this practice safe?", you run a study to find out, rather than speculating from first principles (though you can use speculation from first principles to come up with reasonable hypotheses and narrow down how to best design a study).

Re: Chance of Dying From Backscatter Radiation Same as Chance of Terrorism

#68

Post by KiwiNige »

drawkbox wrote: post #54
roc wrote: post #50

Earlier quoted context omitted.

According to the Bureau of Transportation Statistics, there were 617,977,711 passengers on domestic flights in 2009 [1]. At the (incredibly optimistic) risk rate of 1 in 30 million, that's about 20 people given cancer, each year, if this policy goes forward and these devices become standard procedure. [1] http://www.transtats.bts.gov/Data_Elements.aspx?Data=1

The TSA kills 20 people per year. Keep the hysteria simple. Are you willing to kill 20 people per year to keep safe?

It's the TSA agents standing by the machines all day that are first in the fireing line.

I wonder how long the cancers will take to start showing up.

Re: Chance of Dying From Backscatter Radiation Same as Chance of Terrorism

#69

Post by _delirium »

fluidcruft wrote: post #65
marze wrote: post #63

This discussion is properly focused at the core of the matter, the cost benefit analysis. Some of the costs are easy to see, like the acute embarrassment some experience from an intimate "pat down" if they elect to avoid any risk from x-ray radiation. Others are much more difficult, such as potential health consequences of the x-ray radiation exposure. Since the TSA has refused to disclose the x-ray flux, it is hard…

> Of the 100,000,000,000 or so US domestic air travelers of the past ten years, zero have smuggled a bomb on board, and zero have attempted to. At least two have succeeded in smuggling a bomb on board, but failed to detonate them. Look up the "Christmas bomber" and the "shoe bomber".

Neither of those were "US domestic air travelers"; both boarded U.S.-bound international flights in Europe.

Re: Chance of Dying From Backscatter Radiation Same as Chance of Terrorism

#70

Post by KiwiNige »

noonespecial wrote: post #16

I'm going to go ahead and take this to mean that the TSA just doubled my chances of death. Seems appropriate in the current climate of hysteria, and makes an excellent sound bite.

I suppose it depends on how many attacks are intercepted by the scanners.
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