Dear Science,

The idea of the body scanners at the airport pisses me off. I mean, really: Is there any way this is going to make us safer? I suspect this is all a scam to sell more military equipment to the government. Here’s my question: Are these scanners safe? They use X-rays, right? That can’t be good for you. I travel a ton for work, and I don’t want this to stop me from having children someday.

Frequent Flyer

You’re not the only one concerned about this. Four University of California, San Francisco professors—Doctors Sedat, Agard, Stroud, and Shuman—substantiate your worry.

There are two broad types of whole-body scanners used at U.S. airports. One type of scanner uses radio waves in the millimeter wavelength; the other type uses X-rays. Both work on the same broad principle: bombard your body with an electromagnetic wave and read the signal of the waves as they return. The difference is in how damaging X-rays can be, as compared to millimeter waves. Millimeter waves are nonionizing—they cannot directly damage atoms. X-rays count as ionizing radiation; they’re high enough in energy to rip electrons off atoms and cause all sorts of damage. When those atoms are in your DNA, the result can be mutations. It’s like the difference between being shot by a rubber bullet and a real bullet.

The manufacturers of the X-ray-based scanners claim that the dose of radiation is small, akin to the cosmic radiation one would receive on a cross-country flight or in a chest X-ray. They further claim that these machines deliver only a small, short burst of wimpy X-rays that are able to enter only the layers of the skin—and no further. These arguments are both unproven and unconvincing at this time.

Yes, the dose of radiation is the same as an airplane flight’s worth of cosmic rays—but it’s delivered over a much shorter period of time. When radiation comes on as a trickle over time, there’s time for our cells to repair the DNA between hits. The quick burst of radiation delivered by these scanners—as opposed to the slow trickle delivered by cosmic rays—is potentially far more damaging because our cells’ repair machinery could be overwhelmed by multiple points of damage at once.

Yes, the dose of radiation is similar to a chest X-ray. This type of X-ray, because the waves are strong enough to go through the body, distributes the damage more evenly. Because the waves from these scanners are absorbed entirely in the skin, the radioactive energy is concentrated there.

These are reasonable, and at this point unaddressed, risks. The deployment of backscatter X-ray whole-body scanners is a huge, unconsented radiation-dosing experiment on travelers. Science thinks you should opt out.

Irradiatingly Yours,

Science

Send your science questions to
dearscience@thestranger.com.

Jonathan Golob is an actual doctor.

9 replies on “Dear Science”

  3. Thanks Dear Science. Truly scary and informative piece.

    I was looking at some of the scanner images floating on the internet. The most shocking thing about one image of a woman? I CAN SEE HER SKULL and what looks like FEMUR.

    Jeeezus, when you get X-rays like that in the hospital, THEY MAKE YOU WEAR A LEAD BIB. But air travelers are just walking thru these effing machines sans lead bibs.

    SCARY!

  4. Also, it seems like these scanners are set up out in the open, on the main concourse or walkway in airports.

    Conversely, X-ray (and other radiology-type machines) are usually sequestered away in their own rooms in hospitals/medical facilities. Often these rooms have reinforced cement walls to prevent any radiation waves bouncing into an area where medical staff and patients are.

    I bet the first civil suit regarding these machines will come from a TSA contractor who has to stand next to one of these all day long and develops cancer of the ass, nads or similar.

  5. I am overwhelmingly disturbed and pissed that our government has foisted this unconstitutional and dangerous police state crap on us. On top of that I’m even madder at the idiots out there who say it’s OK with them if that’s what it takes to keep us safe from terrorists. Those morons are making it easy for the TSA to get away with this because they are unwilling to stand up for their rights. I stand up for mine against tyranny but it takes all of us to back this overreaching bureaucratic nightmare off. Finally, none of this back scatter radiation or sexual groping even makes us safer, just look at the way Israel does airport security… theirs works and they say TSA’s way of doing things is nothing more than theater.

  6. Here’s another analysis by a biochemist who has looked at what backscatter does and has concluded that it is not particularly safe.

    And if you opt out you have no guarantee that your tsa agent has changed their gloves between pat downs.

  7. Pretty good response, but I would add the following:

    For millimeter (microwave) scanners: if you cannot feel it hurting you, it is not harming you. I would go through such before allowing my children to do so.

    For x-ray scanners: I would ask you, do you trust radiologists and radiology technicians (people with quite a bit of experience and education)? If you do, then you’re an idiot. Studies have shown that they usually do not have MRI and CT scanners calibrated correctly…that they often deliver twenty times the correct radiation dosage (and an MRI or CT scan, done properly, delivers up to ten times the radiation as a normal x-ray). In light of that, do you think that the TSA has calibrated the x-ray scanners recently and correctly? Are their workers capable of doing so? If you think they have/are, then I would say you are probably NUCKING FUTS! I wouldn’t let my kids go through an x-ray scanner. I would have them patted down instead.

  8. Dear Travelling Public:

    Please do not swallow an explosive device or shove one up your ass. We are not set up to look there yet. Please place it in an area where we can find it and justify our budget for all of this expensive equipment. Also, please tell your mother to lose some weight.

    Sincerely,
    TSA — A Division of Security Theatrics, Inc.

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