More On TSA Backscatter X-rays

Okay, I'll admit it, yesterdays post was an incomprehensible rant that had as much to do with potential overuse of CT medical imaging as it did about the backscatter X-ray systems the TSA bought. So today's is going to be quick simple and to the point:

Pilots are good, pilots fly planes. We trust pilots to take control of large, potentially missile-like objects and use them to safely deliver millions of people and packages every year. Any pilot could easily use their position at the controls to kill everyone on board and cause massive damage on the ground. But we don't trust pilots enough to allow them to carry a pocket knife on the plane, bypass backscatter X-rays, "enhanced pat-downs", etc. Because, hey, they could use anything they snuck on the plane to hijack control of... the plane they're already controlling. It's stupid, illogical, degrading, and - in the case of backscatter X-rays - potentially hazardous. If there is any risk from these machines, pilots are the most at-risk adult population (frequent flying children are probably the most at-risk).

The risk is extremely low, if there is any. It is assumed there is a tiny risk due to the linear no-threshold theory of radiation protection (LNT). LNT is designed to provide a margin of safety. The real risk is probably lower than LNT would lead us to believe. The ionizing radiation levels are small, the exposure time minimal, and the X-rays are very low energy which means that most of the energy absorbed is in the skin. Thus, the risk is almost (but probably not quite) zero. And any lower than almost zero is pretty much zero. However, you're still talking about intentionally exposing the general public to ionizing radiation for no individual benefit to them. That's highly questionable, ethically speaking. Making it more questionable is the fact that there are alternate security systems, including millimeter wave scanners that produce similar (but not quite as clear) images with the use of no ionizing radiation whatsoever (they use radio waves, much like a cell phone does). Why did the government buy the backscatter X-ray systems when millimeter wave systems would serve the same purpose just fine with no ionizing radiation exposure?

Just some more food for thought...