X-Ray Back-Scatter and Junk Pictures

On the previous post, I wrote about the Millimeter wave Scanners in use today at airports.

Now I will write about the other kind of full body scanner, the X-Ray Back-Scatter scanner.

A lot of the previous post was trying to explain about frequencies and wavelengths.

Blue indicates region of millimeter wave energy. Red indicates X-Ray BackScatter.

The reason for that was not only to explain what was meant by millimeter, but also to give some explanation about the differences in energy used with the different types of scanners.

As the energy gets higher in frequency and shorter in wavelength, the energy eventually “changes” in the effect that it has on it’s target. This effect is called ionizing and it consists of subatomic particles or electromagnetic waves energetic enough to detach electrons from atoms or molecules.

The molecule with the electron knocked away then becomes something called a “free radical” molecule which is a molecule with an unpaired electron.

These molecules become chemically reactive because of the change in their molecular structure.

The longer wavelength radiation like infrared or light can produce ionizing damage to molecules, but it requires significantly higher flame or “browning” temperatures. As the wavelength gets shorter and shorter, eventually it gets to the point of ALWAYS being ionizing radiation, as in X-Rays and Gamma rays.

Ionizing radiation produces free radicals even at room temperatures and below. Production of such free radicals is the reason these and other ionizing radiations produce quite different types of chemical effects from (low-temperature) heating.

Free radical production is also a primary basis for particular danger to biological systems of relatively small amounts of ionizing radiation that are far smaller than needed to produce significant heating.

Free radicals easily damage DNA, and ionizing radiation may also directly damage DNA by ionizing or breaking DNA molecules.

So getting back to the X-Ray Back-Scatter scanner. The energy that is being used by the scanner, X-Rays, is ALWAYS ionizing radiation and it will ALWAYS produce free radical molecules.

So does the chance of harm outweigh the benefits that it provides? The official term is called “Statistical Collective Risk”.

Of course, if there are no benefits at all then it will always be a bad choice.

Ideally, there would be no risk at all but in real life everything has risk.

For example, society would have a hard time existing without automobiles but people die everyday while using them. The benefit has been determined to be greater than the risk.

Risk is made even smaller with seat belts, air bags,etc.

Something seemingly benign as a toothbrush has probably killed a few people. Aspirin also probably has taken a few lives.

But again, the benefits have been determined to outweigh the risks.

So what benefits does the X-Ray scanner give? X-Rays are particularly good at contrasting certain materials. Organic matter, like your body, is made of relatively low Z matter like carbon, oxygen, hydrogen, and nitrogen.

This strongly reflects the X-rays, yielding a brighter image. High Z materials, like most metals, will reflect poorly, so they will show up as dark splotches.

So the possibility of catching dense plastics,metals, and explosives on a person boarding an airplane may be better, thus providing additional benefits of increased protection and saving lives.

But would they have caught some of the attempts that terrorist have already made with explosives?

Terrorist can be quite creative in the materials and locations of where they put their tools of destruction. Will they just adapt to the new rules of the game to achieve their goals?

The energy strength of the X-Rays will determine the amount of free radical molecules generated. With free radicals molecules, the risk that some of those will generate cancerous cells will be automatic.

That risk may be say…1 cancer occurrence in 1 million people.

More scans equals more molecules equals more chances of those molecules causing cancer. So the risk becomes greater, maybe 1 cancer occurrence in 100,000.  Again, it is a benefit/risk assessment.

*** What is my opinion?? (not necessarily that of MMA)

I always like to read articles that have all the technical jargon but sometimes not so much on trying to “read between the lines” of what the author thinks. Nice to have something that cuts to the chase, so to speak, at the end. And that is what I am going to do here.

So…what is my opinion of the full body scanners?

Both types are way too intrusive and violate privacy and personal dignity. But polls indicate that the majority of the population are willing to put up with this to insure safety with airline travel.

The Millimeter Wave scanner could be improved quite a bit so that it DOESN’T have to show all the nudity.

But the public relations was handled so poorly, will the public ever think anything else but those strange pictures of nude people when scanners are mentioned? It seems to be relatively safe as far as the energy concerns but some new study may show information that proves other wise.

Fix the pictures to display stick figures like Germany has already done, use pattern recognition, and this may be a valid tool that the public will increasingly accept.

The X-Ray Back-Scatter scanner in my personal opinion should NOT be on the first line of defense. Use that machine only when preliminary indications show that the passenger is to be suspect. There is no doubt that X-Rays have some risk.

Is the risk so small that it’s acceptable?

Perhaps, but the 1 person that gets cancer may think otherwise. These machines excel at baggage and cargo scans.  Keep them in that area of expertise.

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Posted by on December 3, 2010. Filed under Commentary. You can follow any responses to this entry through the RSS 2.0. You can leave a response or trackback to this entry
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15 Responses to X-Ray Back-Scatter and Junk Pictures

  1. A Michael J. Scott Reply

    December 3, 2010 at 2:21 pm

    I agree that Homeland Security could have done a MUCH better job at selling this. Had they done it right they could have convinced people that the scans were actually good for you. Perhaps they should study the strategies employed by Herr Dr. Goebbels. He convinced a whole nation that the Jews were evil and war was a good thing.

    • Krell Reply

      December 3, 2010 at 2:35 pm

      I agree with that Mike. The Millimeter wave can be a valuable tool for security and passenger feeling of safety about flying.

      The unfortunate “Nudie pictures” publicity and the blatant privacy issues has done a disservice to it’s potential.

      Doesn’t have to be that way. Fix it and I would have no problem in stepping in a MMW scan.

      But I would not walk through a X-Ray Back-Scatter machine if I could avoid it. I would spend the effort to reroute flights if possible.

      I feel that strongly about it. But I have also stopped Dentists midway through a “routine” dental X-Ray with a “What the hell you think your doing?” speech.

      I say go ahead only if they agree to stand right next to me without wearing the lead apron while they take the X-RAY. So far, not a single Dentist has taken me up one it.

      I did have to get a GI X-Ray one time, didn’t have a choice.

      I was sure to wear my “Uranus is right here, picture of the solar system” underwear.

  2. Holte Ender Reply

    December 3, 2010 at 4:12 pm

    What about radio waves? They can take pictures, from Earth, of the Solar System and beyond and tell you the mass you are looking at is made of by the colors. Just wondering. Probably showing my technical ignorance by asking such a question but inquiring minds want to know.

    • Krell Reply

      December 3, 2010 at 5:02 pm

      Holte, that is a great question. Hopefully I can explain it but I’m going to do it in a indirect way.

      Whenever you hear a sound, say it’s a band playing, your ears and brain are doing a spectacular thing. Even though you hear all the sounds at the same time, your mind is able to process the sound and break it down and treat it as separate sounds.

      You don’t hear a sound mush….you hear a guitar…a drum…a singer…a bass. Although you consciously don’t know it, your mind is performing a very complex task.

      Well, the mind can do it for sound…but it would be much to complex to do it for higher frequencies like light.

      But that doesn’t mean that the music, “the light music”, is still not there.

      Spectroscopy is the study of the components of “energy music” in a way. When you burn something, to your eyes it just gives off light. But if you were able to break the light down to it’s “music” so to speak, it’s components, you can tell by “notes” and the loudness of the “notes” what the material that is burning consists of.

      Burning is not the only way of releasing those “notes”. This is a link that lists the wide varieties of “ringing the bell” to release the “notes”


      I hope my music metaphors helped a little and aren’t confusing the issue. That example has always helped me to understand a little of it.

      • Holte Ender Reply

        December 3, 2010 at 5:26 pm

        Thanks for you answer, it did help. Knew there had to an explanation.

      • A Michael J. Scott Reply

        December 3, 2010 at 8:16 pm

        OK…Impressed. As Jess said: Thank you Professor Krell. I learned a lot and I mean that sincerely.

        • Jess Reply

          December 3, 2010 at 8:44 pm

          MH still has to deal with him at home, so we should probably go easy on the compliments, so he doesn’t get all big headed about it 🙂

          • Krell Reply

            December 3, 2010 at 10:49 pm

            That’s not a problem. If I ever start to get a big head, I can always go back to some of your comments, Jess.

            Just a couple of ones like….”How can I miss you if you won’t go away?”…will fix me right up. 🙂

  3. Mother Hen Reply

    December 3, 2010 at 4:47 pm

    So instead of “don’t touch my junk,” perhaps the mantra should be,”Don’t nuke my junk?”

  4. Tim Waters Reply

    December 3, 2010 at 6:01 pm

    So krell what your saying if I’m following you is Lawrence Welk was an evil genius that gave us cancer hence the distracting bubbles……..POP!

    • Krell Reply

      December 3, 2010 at 6:09 pm

      Tim, that was beautiful….and a one and a two.

  5. Jess Reply

    December 3, 2010 at 6:33 pm

    I learned something else today, thank you professor Krell.

    • Krell Reply

      December 3, 2010 at 8:46 pm

      That’s a good day, o’person with objects that begin with a K.

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