Data of low level x-rays and health goes back to around the 1950s. A cursory search of PubMed of the National Institutes of Health will reveal a multitude of peer-reviewed articles with some having free access to full text. Just did a quick search and I found an article showing research on rats that had been exposed continuously to low-level x-rays for 18 months at about twice the level recommended for maximum dosage for those working directly with nuclear material (i.e. CT-scanners, nuclear power plant). Electron microscopy of skin from the rats showed redistribution of biometals in the keratinized layer of the skin (i.e. the layer of dead, crystallized skin cells that protects the living cells underneath). Nothing mentioned about malignancies or cell hyper- and/or metaplasia. Reference: Jyotirmoy Chatterjee, Kuntala De, SK Basu, AK Das. "Low-level X-ray exposures on rat skin." Biological Trace Element Research. 1994 Dec;46(3):203-10.

For specific information about dosages from these airport body scanners, go to the following peer-reviewed article: O Hupe, U Ankerhold. "X-ray security scanners for personnel and vehicle control: dose quantities and dose values." Eur J Radiol. 2007 Aug;63(2):237-41.

So basically, a scan with this new airport scanning device would result in a dose of radiation equivalent to 0.29% of a typical long-haul flight (so about 350 times more radiation exposure/absorption as the scanner). Do people avoid long-haul flights due to health risks associated with radiation exposure? As far as I know, there has never been a case of cancer or serious chronic (physical) condition linked to flying too much, otherwise everyone with a shinny FF card should be trading down to the pleb levels asap.

For information about recommended maximum (absorbed) dosage, you can probably find information on the websites and/or publications of the US Nuclear Regulatory Administration or the US Environmental Protection Agency. The information is also included the article referenced above. 1 mRem is the recommended maximum absorbed dosage of background radiation for a member of the public from approved devices. That is about 10,000 times the dosage received from a single airport body scan. So you could be scanned 10,000 times, in a sense, before you received the maximum safe dosage of background radiation as a member of general public.

Background radiation from natural sources (i.e. cosmic background radiation, radon in the soil, naturally occuring uranium etc.) is even higher than 1 mRem, at about 2.5 mRem. Man-made background radiation from nuclear and coal-fired plants, medical devices, residual fallout from atmospheric weapons testing etc. amounts to about 1.2 mRem for a typical person in a developed/rich-income country, compared to about 0.6 mRem for a worldwide average. This information comes from a UN Scientific Committee on the Effects of Atomic Radiation.

For information from the popular press, a google search will lead one to a New York Times article that addresses both the pro and con arguments from a health perspective, as well as the (in my opinion more important) privacy and civil liberties concerns.

New Airport X-Rays Scan Bodies, Not Just Bags

So basically, conclusion from the quickly slapped together information above that the radiation dosage from an airport body scanner is pretty much negligable and/or non-existant, with long-term effects easily deducable from having studied the long-term effects of normal radiation exposure (it being negligable to health) as well as rat studies showing signifigantly higher exposure produced no mention of malignancies.

I can't provide any more information. I'm not a physicist, so anybody with greater expertise/knowledge please indulge us. I'm just someone with what I consider to be an informed opinion. So do with the information what you want.

I still think beating my chest about how the risks of these scanners are unknown and possibility dangerous will get me more laughs than serious due consideration, and discredit me to the point where more important concerns about privacy and civil liberties will not receive a receptive or attentive audience.

For bocastephen, I have no information handy, in terms of peer-reviewed journals or university textbooks, that say anything about clothing/skin penetration and radiation. This is what I know to be fairly accurate: up to about 3000nm, radiation penetrates the upper layer of skin, which are exposed the same levels (if not more) levels of radiation from background sources and even more from the sun across the spectrum (which is why your skin gets hot under the sun). For all intents and purposes, this is not skin penetration, in the sense that the subdermal layers are reached and damaged, such less more sensitive to damage underlying tissues and organs. As such, the radiation, in my estimation, will not cause cellular damage to the degree that cancer will result, unless you have Xeroderma pigmentosum (an exceedingly rare genetic disorder predisposing people to skin cancers). So basically, you assertion "if it penetrates clothing, it will penetrate my bare skin" is inaccurate or at best inconclusive and does not provide sufficient information. Do you have sources to show this radiation will penetrate your skin?

And your linked article about ultrasonic transducers only seems applicable to materials such as metals and plastics; the article makes no reference to whether or not this technology is applicable and/or safe for use on humans, unless I am missing something.

Whew... so much for the last 20 minutes. Need to get going...