Because I don't know a loosing battle when I see it
Looks like I was wrong in my previous post. I said that there wasn't enough science to back up worries that the radiation exposure from the new full-body airport scanners is harmful. And I tried to put things into perspective by talking about relative radiation doses. Where I was wrong is that there is evidence and study about the harm that these scanners can cause.
But before we go there, let me review what I said before. Basically I said what these guys were saying in this letter sent to Joseph Holdren, the Assistant to the President for Science and Technology (a job that I lust after in my darkest dreams, by the way).
The letter outlines concerns that several very well-known scientists (I have read papers by Stroud) about the radiation levels that people are exposed to in the full body scanners now in airports.
They are worried about the calculation of effects of radiation absorption in just the skin versus normalizing it over an entire body. They also talk about how the radiation from the scanners is different from other forms of radiation.
They are worried that independent studies do not exist, and that the data that the FDA, TSA, and scanner manufacturers must have is not being shared.
They list some specific populations that, if the radiation is indeed harmful, might be even more at risk than average.
They talk about how vulnerable a person being screened would be if the machine and its failsafes were to fail.
They outline a possible approach to assembling an independent team to test the scanners.
And they spend an entire paragraph explaining that the government doesn't exactly have a stellar track record when it comes to figuring out what's safe and what isn't, and that there hasn't been enough time to study the long-term effects of these scanners.
What the letter doesn't say is that the radiation from the scanners is definitely harmful, or that those populations definitely are at risk. They are rightly throwing red flags, pointing out things they're worried about but don't have enough information to be able to make a determination. They're calling for more information, for more study.
Remember how I said, "My advice is to not use 'radiation exposure' as a reason why the scanners are a bad idea. The science is not there to back it up..." Pretty much what those guys were saying, they just had more specific concerns to go with the call for more study.
So where was I wrong? There has been some good science done to figure this out. What did they find?
Emphasis is mine.
Still, though, it's radiation, right? Might cause cancer, right?
So yes, sorry folks, I was wrong. There is science being done, and so far it indicates the scanners aren't harmful. In fact, there's a certain amount of disingenuousness in claiming that such low levels of radiation are harmful at all.
Look. I understand the temptation here. Science is a powerful tool in arguments like these. It can effectively shut down opposition. But this isn't one of the times when we get to use science like that.
Maybe someday we will. Maybe someday we'll find out that these scanners are very dangerous--I still think we need more study. The calculations Rez and Mossman do in their paper are good, I can't find fault with them...but ultimately they're just a first pass. We need more study.
In the meantime, we're going to have to find other reasons to argue that they're a bad idea--which was my ultimate suggestion from the start. Reasons like:
So, to summarize: These scanners are a bad idea. They're bad for lots of very good reasons...but we not only can we not say radiation is one of them, the very implication is borderline disingenuous.
But before we go there, let me review what I said before. Basically I said what these guys were saying in this letter sent to Joseph Holdren, the Assistant to the President for Science and Technology (a job that I lust after in my darkest dreams, by the way).
The letter outlines concerns that several very well-known scientists (I have read papers by Stroud) about the radiation levels that people are exposed to in the full body scanners now in airports.
They are worried about the calculation of effects of radiation absorption in just the skin versus normalizing it over an entire body. They also talk about how the radiation from the scanners is different from other forms of radiation.
They are worried that independent studies do not exist, and that the data that the FDA, TSA, and scanner manufacturers must have is not being shared.
They list some specific populations that, if the radiation is indeed harmful, might be even more at risk than average.
They talk about how vulnerable a person being screened would be if the machine and its failsafes were to fail.
They outline a possible approach to assembling an independent team to test the scanners.
And they spend an entire paragraph explaining that the government doesn't exactly have a stellar track record when it comes to figuring out what's safe and what isn't, and that there hasn't been enough time to study the long-term effects of these scanners.
What the letter doesn't say is that the radiation from the scanners is definitely harmful, or that those populations definitely are at risk. They are rightly throwing red flags, pointing out things they're worried about but don't have enough information to be able to make a determination. They're calling for more information, for more study.
Remember how I said, "My advice is to not use 'radiation exposure' as a reason why the scanners are a bad idea. The science is not there to back it up..." Pretty much what those guys were saying, they just had more specific concerns to go with the call for more study.
So where was I wrong? There has been some good science done to figure this out. What did they find?
Systems based on the detection of Compton backscattered X-rays have been deployed for screening personnel for weapons and explosives. Similar principles are used for screening vehicles at border crossing points. Based on well-established scattering cross sections and absorption coefficients in conjunction with reasonable estimates of the image contrast and resolution the entrance skin dose and the dose at a depth of 1cm can be calculated. Effective dose can be estimated using the same conversion coefficients as used to convert exposure measurements to effective dose. We show that effective dose is highly dependent on image resolution (i.e., pixel size).The effective doses for personnel screening systems are unlikely to be in compliance with the ANSI standard NS 43.17 unless the pixel sizes are greater than 4 mm. Nevertheless, calculated effective doses are well below doses associated with health effects.
Emphasis is mine.
Still, though, it's radiation, right? Might cause cancer, right?
The major public health effect of concern at low doses of ionizing radiation is cancer. There is clear evidence of cancer induction at effective dose above about 200 mSv. Below an effective dose of about 100 mSv radiogenic cancer mortality risk estimates for all cancers is highly uncertain. It is not possible to determine reliably whether a radiogenic risk is present in an X-ray screening population because of the high spontaneous incidence of cancer and multifactorial nature of disease causation.
Use of collective dose to estimate public health impacts when large populations are exposed to trivial doses is inappropriate and not reasonable. The assumptions implicit in the collective dose calculation conceal large biological and statistical uncertainties. If an individual passenger is not harmed by X-ray screening then the population isn’t either.
So yes, sorry folks, I was wrong. There is science being done, and so far it indicates the scanners aren't harmful. In fact, there's a certain amount of disingenuousness in claiming that such low levels of radiation are harmful at all.
Look. I understand the temptation here. Science is a powerful tool in arguments like these. It can effectively shut down opposition. But this isn't one of the times when we get to use science like that.
Maybe someday we will. Maybe someday we'll find out that these scanners are very dangerous--I still think we need more study. The calculations Rez and Mossman do in their paper are good, I can't find fault with them...but ultimately they're just a first pass. We need more study.
In the meantime, we're going to have to find other reasons to argue that they're a bad idea--which was my ultimate suggestion from the start. Reasons like:
- Failsafes fail. You COULD get a dose of harmful radiation from one of these things if things went wrong.
- They're completely unacceptable for transfolk.
- They're not particularly good at finding explosives.
- They're simply an unacceptable invasion of privacy, with insufficient guarantees that the images aren't saved or shared.
So, to summarize: These scanners are a bad idea. They're bad for lots of very good reasons...but we not only can we not say radiation is one of them, the very implication is borderline disingenuous.