Monday, January 11, 2010

Full Body Scanners

I was wondering when it would happen.
There's an obvious question whenever you bathe a body in radiation -- what are the health effects, if any?
From the "Big Government" blog:

Are Total Body Scanners Safe? The Jury Is Still Out


....

The TSA website represents the full body scanner as a safe method of screening. However, not only are we giving up our privacy, we are also playing Russian roulette with our safety. It is important to note:

1. No long term safety tests have been conducted on these scanners

2. The energy produced by T-rays gives off heat and lies close to the laser range.
Because of this, there is a question about how safe these machines would be in the hands of individuals who may not be as well trained as a radiology technician. (Theoretically there may be damage associated with prolonged thermal exposure.)

3. Alexandrov et al. at Los Alamos National Laboratory theorized that the thermal energy given off by T-rays can damage DNA by unwinding or unzipping the double helix strands of DNA. This could possibly lead to mutations as the DNA attempts to repair itself.

It is clear that the rush to deploy these machines may put the public at unacceptable risk. The questions about safety for pregnant women, children, and the possibility of increased cancer risk need to be answered before these machines are put into place. It simply is not clear whether the risks are outweighed by the stated benefits.

Infrared lasers are much safer than visible light lasers for a couple of reasons.  Being invisible, the eye is less likely to try and focus on them, so much less chance of burning the retina.  Also, the infrared wavelengths don't penetrate the eye quite as well as visible light does.

When I was in college, the going theory was that microwaves did their damage by heating tissue.  As long as the power level was low enough that you didn't cause too much heating, microwaves did no long-term damage.  But then again, there were Russian scientists who claimed microwaves could cause behavioral problems at levels a tenth of a percent of what US science considered safe.  We seem to have quit arguing over microwaves, possibly because shielding has improved, but other forms of radiation, including cell phone transmissions, are hotly contested.

In any event, once people start speculating about the health effects of millimeter wave radiation  -- um excuse me, make that *RAY-DEE-AAAAYYYY-SHUN* -- I suspect we won't have to worry about invasions of privacy.  They won't get FDA approval.

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