Five-hundred body scanners, split about evenly between the two technologies, are deployed in U.S. airports. The X-ray scanner, or backscatter, which looks like two large blue boxes, is used at major airports, including Los Angeles International Airport, John F. Kennedy in New York and Chicago's O’Hare. The millimeter-wave scanner, which looks like a round glass booth, is used in San Francisco, Atlanta and Dallas.
Within three years, the TSA plans to deploy 1,800 backscatter and millimeter-wave scanners, covering nearly every domestic airport security lane. The TSA has not yet released details on the exact breakdown.
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Add CommentI can't believe how incomplete and misleading this article is. Do some research next time! Everybody (except apparently SciAm writers) is aware that the dosage of X-rays on backscatter machines is all concentrated near the skin, and thus CANNOT BE COMPARED to the same dosage from other sources of X-rays which distribute their energy more evenly throughout the body's tissues. Backscatter machines are thus many times more dangerous than other sources of ionizing radiation at the same measured dosage.
Reply | Report Abuse | Link to thisFurther, backscatter machines have been found to be seriously miscalibrated, causing them to emit far more radiation than specified.
The "health issue" "for some" you're referring to includes apparent cancer clusters among the unfortunate operators of these machines, who are bombarded day after day with that large fraction of X-rays which get scattered at obtuse angles, irradiating bystanders.
In practice, many passengers are being sent through the machines multiple times. ("You forgot to remove your watch, sir.")
Just as supposedly every passenger is at some risk of terrorist attack, if every passenger were also subject to a backscatter screening, then the actual risk of deaths by cancer means the machines are "deadlier than the terrorists." (-Bruce Schneier)
The machines were never properly approved in the USA. They should now be properly withdrawn. EVERYWHERE.
(Washington, D.C.) – U.S. Rep. Rush Holt, a scientist and the Chairman of the House Select Intelligence Oversight Panel, Friday wrote the Administrator of the Transportation Security Administration (TSA), reiterating his concerns about the use of body imaging technology, notably about potential health effects and the effectiveness of the screening to detect the full range of explosive threats known or anticipated to be used by potential terrorists.
Reply | Report Abuse | Link to thisEarlier this year, the Congressional Biomedical Caucus - of which Holt is a co-chair – hosted a briefing by Dr. David Brenner of Columbia University on the potential health effects of “back scatter” x-ray devices. According to Dr. Brenner, the devices currently in use and proposed for wider deployment deliver to the scalp “20 times the average dose that is typically quoted by TSA and throughout the industry.” Dr. Brenner has pointed out that the majority of the radiation from X-ray backscatter machines strikes the top of the head, which is where 85 percent of the 800,000 cases of basal cell carcinoma diagnosed in the United States each year develop.
According to Dr. Brenner, excessive x-ray exposure can act as a cancer rate multiplier, which is why Holt has urged the government to investigate thoroughly the potential health risks associated with this technology. In August, Holt wrote to the House Committee on Appropriations calling for a freeze in funding for any further full-body scanning devices employing “back scatter” technology until the GAO completes its examination of the technology.
“I appreciate the challenges we face in trying to prevent terrorists from boarding American airliners. That same background also gives me an understanding of why TSA’s current obsession with fielding body imaging technology is misguided, counterproductive, and potentially dangerous,” Holt writes.
@Reggie222
Reply | Report Abuse | Link to thisNobody expects something called Scientific AMERICAN to be really objective when Europe is better than America.
What!? Europe refuses to cooperate in the War on Terror? (sarcasm alert for the more dense) Maybe those people over there are on to something. Meanwhile back here in the US, the sheeple continue to obey their masters.
Reply | Report Abuse | Link to thisPlease source your statements before spraying nonsense about back-scatter technology. All the studies on the matter have concluded like the article said (i.e. no health effect).
Reply | Report Abuse | Link to thisI'm not convinced of the usefulness of these devices, but discarding them for so-called health concern is just plain ignorance.
“Since January 2010, advanced imaging technology has detected more than 300 dangerous or illegal items on passengers in U.S. airports nationwide.”
Reply | Report Abuse | Link to this...but of course one must ask the question - how many would have been detected by other simpler / less expensive / less intrusive / potentially less dangerous technologies ?
Brian
This should all be analyzed using cost-benefit analysis. How many lives saved if we use the scanner versus the health costs. But once again beliefs start getting in the way. Most people will accept the old over the new simply because the new is unknown. Like if you have alot of headaches and the doctor says that you need to get a catscan, you go and get it. Yet a catscan is a huge dose of radiation. But walk through a device that is far far less a dosage? NO WAY! And we have protocols for operators of catscans and the like. All of this stuff is really very old technology being used somewhere new.
Reply | Report Abuse | Link to thisNow, having said that, I am not sure how useful it is and it is costly money wise. Seems like passive 'scanning' by dogs or odor-detectors is a better way to check for dangerous materials. Don't steal jobs from dogs ;)
I invite anyone who thinks I've sprayed nonsense or that "discarding them for ... health concern is just plain ignorance" to carefully review this UCSF letter of concern.
Reply | Report Abuse | Link to thishttp://www.npr.org/assets/news/2010/05/17/concern.pdf
why use a potentially risky technology when a safer one is just as good. If an airport is using millimeter-wave scanners, I'll walk through. Otherwise, I'll get the blasted pat-down. (And no, I wouldn't get a CAT scan just because my doctor suggested it. Ask for an MRI instead.)
Reply | Report Abuse | Link to thisMany thanks for this paper (and informed comments) that allows us to easily detect a X-ray scanner from a millimeter-wave scanner.
Reply | Report Abuse | Link to thisBeside this “scientific” subject, is it true that we can refuse such scanner for a classical “manual” scanner?
So that's the only basis you have to affirm these scanners are dangerous ?
Reply | Report Abuse | Link to thisConcerns by a few scientists, not having even basic knowledge in the carcinogenic effect of ionizing radiations[1] and who did not actually assess their hypothesis with you know, at least some modeling. If you pay attention to this letter (that's not a study, just a letter) you'll see that they're not even consistent with their statements:
First they say it would not be dangerous if the energy was spread in the body, but it may be because the energy is concentrated on the skin (statement refuted by other scientists: effective dose to the skin is 89 thousandth of the regulatory limit).
Then they say they have concern for tissues that are under the skin *facepalm*
I know it's easy to scare people by saying their baby in the womb or their bollocks are at risk, but at least they could be consistent with their claims, all you're showing us is politics hiding in the name of science.
This letter has been debunked by the FDA (http://j.mp/sxoFZM) providing all the link to the *studies* actually calculating the effective dose to the skin.
[1] It's worth noting that the other scientists working at the UCSF Radiology department where this letter emanated said that it was "plain wrong" and written by people who "are totally unrelated to radiation"
Source: http://j.mp/uMIzGc
Definitely, US defense department has some explaining over why they expose their citizens to health risk.
Reply | Report Abuse | Link to thisLast times I heard, airplane pilots were especially concerned - they were forced to pass through scanners every day at work. Apparently nobody thought that a pilot who wants to hijack a plane doesn't need a scissors.
300 "dangerous or illegal" - note the OR
Reply | Report Abuse | Link to thisE.g. longswords are deemed dangerous, marijuana is illegal and bottles of drinking water not allowed.
Exactly how many firearms, explosives, sabers, large knives, etc.?
Exactly how many illegal items, unfit for terrorism?
It certainly is a health issue; only the dummies at DHS in D.C. don't care who they kill.
Reply | Report Abuse | Link to this89thousandth of the regulatory limit? The scanners are said to deliver .02 microsieverts. Above 10 microsieverts is risky. That alone is 1/500. On top of that the scanners deliver all of their radiation to your skin, increasing the risk. Either the regulatory limit is too high or you are making statistics up.
Reply | Report Abuse | Link to thisI have had two skin cancers by the time I was 30 - directly irradiating all of your skin every time you fly is hazardous. This technology will never prevent a terrorist from smuggling a weapon on a plane, as had already been proven. This technology is dangerous, intrusive and unnecessary.
the s.t.a shod no what a terrorist look like we the u.s.citizen shod not be going true some shit like this wen we flying it make no seance
Reply | Report Abuse | Link to thisPlease take the time to read the FDA paper, you will learn that the regulatory limit for public exposure to ionizing radiation to the skin is 50mSv [1], not 10µSv ! 0.2µSv is 1/250000 of 50mSv.
Reply | Report Abuse | Link to thisThe skin has evolved to be far more resistant to ionizing radiation than the internal organs, because it is exposed daily to a very nasty ionizing radiation named ... UV. But guess what, I'm sure the clueless idiots who wrote their "Letter of Concern" are happy sunbathing in their garden and reading how much coverage and attention they got from the news who are propagating their nonsense.
[1] NCRP report no. 116 Limitation of exposure to ionizing radiation (1993), page 56