Molecular Biologist Jason Bell On Dangers Of The Pornoscanners
Bell writes at myhelicaltryst on how the scanners work and why we shouldn't go along with government claims that they are safe:
Essentially, it appears that an X-ray beam is rastered across the body, which highlights the importance of one of the specific concerns raised by the UCSF scientists... what happens if the machine fails, or gets stuck, during a raster. How much radiation would a person's eye, hand, testicle, stomach, etc be exposed to during such a failure. What is the failure rate of these machines? What is the failure rate in an operational environment? Who services the machine? What is the decay rate of the filter? What is the decay rate of the shielding material? What is the variability in the power of the X-ray source during the manufacturing process? This last question may seem trivial; however, the Johns Hopkins Applied Physics Laboratory noted significant differences in their test models, which were supposed to be precisely up to spec. Its also interesting to note that the Johns Hopkins Applied Physics Laboratory criticized other reports from NIST (the National Institute of Standards and Technology) and a group called Medical and Health Physics Consulting for testing the machine while one of the two X-ray sources was disabled (citations at the bottom of the page).These questions have not been answered to any satisfaction and the UCSF scientists, all esteemed in their fields and members of the National Academy of Sciences have been dismissed based on a couple of reports seemingly hastily put together by mid-level government lab technicians. The documents that I have reviewed thus far either have NO AUTHOR CREDITS or are NOT authored by anyone with either a Ph.D. or a M.D., raising serious concerns of the extent of the expertise of the individuals and organizations evaluating these machines. Yet, the FDA and TSA continue to dismiss some of the most talented scientists in the country...
With respect to errors in the safety reports and/or misleading information about them, the statement that one scan is equivalent to 2-3 minutes of your flight is VERY misleading. Most cosmic radiation is composed of high energy particles that passes right through our body, the plane and even most of the earth itself without being absorbed or even detected. The spectrum that is dangerous is known as ionizing radiation and most of that is absorbed by the hull of the airplane. So relating non-absorbing cosmic radiation to tissue absorbing man-made radiation is simply misleading and wrong.
Furthermore, when making this comparison, the TSA and FDA are calculating that the dose is absorbed throughout the body. According the simulations performed by NIST, the relative absorption of the radiation is ~20-35-fold higher in the skin, breast, testes and thymus than the brain, or 7-12-fold higher than bone marrow. So a total body dose is misleading, because there is differential absorption in some tissues. Of particular concern is radiation exposure to the testes, which could result in infertility or birth defects, and breasts for women who might carry a BRCA1 or BRCA2 mutation. Even more alarming is that because the radiation energy is the same for all adults, children or infants, the relative absorbed dose is twice as high for small children and infants because they have a smaller body mass (both total and tissue specific) to distribute the dose. Alarmingly, the radiation dose to an infant's testes and skeleton is 60-fold higher than the absorbed dose to an adult brain!
via BoingBoing
I haven't seen the setup for the porno scanners -- but the typical hospital setup is to have the person in a room with the x-ray tech behind a wall when (s)he is "shooting". And that is with "direct" x-ray machines.
Here we have backscatter scanners. The definition of scatter includes:
I would like to see the TSA agents wearing the dosimeter badges for a week or month and see what they look like.
What would be really great is to have all flight attendants and pilots wear them. And then submit them at the end of a month.
Jim P. at November 28, 2010 4:15 AM
> I would like to see the TSA agents wearing
> the dosimeter badges
Oh, have no fear... Treatment of their carcinomas will be provided...
Crid [CridComment at gmail] at November 28, 2010 6:45 AM
And remember, the airline fuckheads are exempt.
...Sorry. Not all airline employees are fuckheads. But the commenter Skippy on this blog has made a bad impression.
Here's a new rule of thumb: If you've been excused from the intrusive inspection routines that other fliers can't escape, you're probably fucked in the head, a real asswipe of a human being.
If you find any exceptions, list them below. I mean it: NAME them.
1. _________________
2. _________________
3. _________________
4. _________________
Crid [CridComment at gmail] at November 28, 2010 6:49 AM
Remember Therac-25 where a number of machines had glitches and killed people by over-dosing people with radiation.
http://en.wikipedia.org/wiki/Therac-25
The Former Banker at November 28, 2010 12:36 PM
I hope that these units are removed, but his complaints are a bit of a red herring. You do not need a Phd or MD (?) to evaluate the potential error states of these systems. There are formal methods for evaluating such systems and they don't require a specialized degree to employ. Also an MD would have no idea of what they were looking at. This is where he shows his skirt. Just because he don't understand their design, he assumes that no one with out an advanced degree can. Perhaps many of his questions have been answered, but he didn't understand the answers. That seems likely.
omololomo at November 28, 2010 1:09 PM
"Here's a new rule of thumb: If you've been excused from the intrusive inspection routines that other fliers can't escape, you're probably fucked in the head, a real asswipe of a human being.
If you find any exceptions, list them below. I mean it: NAME them."
1. Capt Sulley
2. My father
3. Oh what the hell, let's just go down the roster of the pilots unions.
It's not right that the FAs are still subjected to the aggressive search procedures. (Well, it's not right that anyone is but scanning the FAs is
Elle at November 28, 2010 3:00 PM
Sully is a very nice man. I'm sure your father has his charms as well.
But if you want to make a living doing that, I see no reason for you to be excused from the intrusions that the rest of us deal with. I don't people sticking their hands down my father's underpants, either... Exactly who do you think you are? What makes your Dad so special? Nope, no exceptions. Not for congress, not for Obama's daughters. Unless....
...Unless you're ready to concede that it's all bullshit, and NO American should be putting up with this.
Crid [cridcomment at gmail] at November 28, 2010 3:34 PM
...Unless you're ready to concede that it's all bullshit, and NO American should be putting up with this.
Yes yes yes yes yes yes
There is no way to put in place a system that can eliminate the risk of terrorism entirely, but the false belief that we can attain that impossible goal by subjecting people to ever more intrusive and humiliating measures now trumps all reason in airline security. If we keep down this path, the logical endpoint is cavity searches for everyone - children, too! Because you can guarantee that someone, at some point in time, is going to stuff some explosives up his ass and get on a plane and try to ignite them. That person will probably fail, and if he does, it will much more likely be due to the actions of flight attendants and other passengers, not TSA automatons.
The fact that these machines have not be shown to be safe, and that there is no level of ionizing radiation that doesn't cause at least some cellular damage, is another reason why this must stop. But it's not the most important one.
Christopher at November 28, 2010 4:26 PM
Guys, I don't buy this intro at all.
The manufacturer knows what the emitter power is and the wavelength of the x-ray.
Reminder: an x-ray is a high frequency radio wave capable of penetrating materials of low density. It deposits energy depending on the energy of the beam divided by the volume being impacted. See here.
So the energy deposition rate is known, somewhere.
Radwaste at November 28, 2010 4:50 PM
Further, this paragraph,
"Most cosmic radiation is composed of high energy particles that passes right through our body, the plane and even most of the earth itself without being absorbed or even detected. The spectrum that is dangerous is known as ionizing radiation and most of that is absorbed by the hull of the airplane. So relating non-absorbing cosmic radiation to tissue absorbing man-made radiation is simply misleading and wrong."
is possibly intentionally misleading. I can only suppose that the individual has missed the point AND never read anything about exposure, measured by the way, in flight.
"Most cosmic radiation" is irrelevent. We do not care about neutrinos; the particles that affect your body are alphas, betas, gammas and neutrons. As this article shows, x-rays of concern act much like gammas. They don't affect your skin the same as they do deep tissue, and there are units you need to understand before you freak out about anybody's article, so please read up.
The last sentence of the quoted paragraph is flatly not what is being done. That's a red herring.
Radwaste at November 28, 2010 5:04 PM
One more thing for Jim P and his readers: it's called "backscatter" because the detector is not in line with the beam. No one is holding up film on the other side of you. The x-ray detector is working just like your eyes do when light is shined on someone: making an image from what is reflected from the object. It's just doing it in another part of the spectrum.
Exposure from the backscatter device is lots lower than the conventional beam at your dentist, because it doesn't have to go through you.
Radwaste at November 28, 2010 5:09 PM
All of you going on about how "safe" these things are, need to back the hell up and answer a very important question. Why does it take 10+ years to approve a medical device or drug, yet these machines have not gotten that amount/indepth testing and documentation? Who is going to be the one to tell the next generation of cancer victims "It was for the greater good!" as they suffer the intentionally inflicted pain of sugery, chemo and *more* radiation?
I am a breast cancer survivor. I was only 33 when I was diagnosed with stage 2 Invasive ductile carcinoma. The same disease had killed my grandmother. I was young and fairly healthy otherwise, so my treatment was very aggressive, especially the chemo. I have 2 daughters, the younger was only 5 at the time, that I had to send to live with relatves because I could barely take care of myself during chemo. The reason I trusted my doctors and their treatment plan was that they could show me how thorough testing and certification of these treatments had been, as well as hard data on survival rates given different levels of treatment.
So, when I can see that these machines have been as thoroughly tested as medical tests/procedures have been, I may consider flying again.
Kat at November 28, 2010 5:30 PM
Exposure from the backscatter device is lots lower than the conventional beam at your dentist, because it doesn't have to go through you.
So very true -- it only has to penetrate the layer of clothing people are wearing. Would you be willing to stand next to the machine as it does 500 scans per day? What about 750? How about 1000?
Should a Geiger counter be situated next to each machine?
What if I did the radiation treatments and have had the "limit" for my lifetime? What about those who have/had seed treatment for prostate cancer?
This is theater -- not security.
Jim P. at November 29, 2010 9:29 AM
Jim P - one of the advantages an x-ray machine has, vs an isotopic source of gammas, is that the beam can be steered. It's not a laser, but you can stand right next to one and get no exposure. Standard instructions for the tech at the dentist or hospital establish a routine to lessen the risk of foolish behavior. Think of the guy copying his butt on the Xerox machine. It's a very good question for the screeners to ask, though, because materials in the vicinity can redirect the beam.
Kat, I hope this doesnt come across as "how safe these are" - but the physics of this exposure is quite a bit simpler than drug interaction testing.
An impinging particle or wave does one of only three things to a given cell: nothing, as most of the cell is water; damage, which the cell repairs; damage, which the cell does not repair. Cells which develop a cancerous state fall into the latter category.
You'll note that a treatment for cancer actually calls for radiation. This is because cells which reproduce rapidly (often), like cancerous cells, are more vulnerable to ionizing radiation. So cells like those of the skin, ironically, are more likely to become cancerous due to radiation than some other parts of the body. You don't hear about nerve cancer, for instance.
Each person has a different susceptibility, generally. The actual criterion for the ALARA program at work - As Low As Reasonably Achievable - recognizes that there is NO exposure which can be considered "good", and our procedures insist that there be none unless a direct benefit can be shown.
And that's where I came in, showing that air travel is one of the least effective attack points for a would-be terrorist. That is, it would be if the public didn't fear flying in the first place.
Radwaste at November 29, 2010 10:02 AM
It's possible to calculate the local dose to the skin that these machines can deliver, and to convert that to an effective dose - a full body dose that would have the same effect. This takes into account the differing sensitivities of different parts of the body to radiation. The authors of this paper:
http://www.public.asu.edu/~atppr/RPD-Final-Form.pdf
come up with a figure of 0.8 to 0.9 microsieverts (0.08 to 0.09 mrem), which is over 4 times higher than the manufacturer's claims, but still only a tiny fraction of the 5 mrem or so that Amy would have picked up from cosmic rays while flying from LA to Paris.
If a scanner malfunctioned and its fail-safe mechanism did not detect the fault and shut down the beam, then it could deliver a harmful dose. I don't have any data on the plausibility or probability of this series of events.
Martin at November 29, 2010 11:59 AM
I'm seeing reports that over the Thanksgiving weekend, the body scanners at major airports were turned off (and the grope-search procedures were eased), so as to thwart the national opt-out day protest. If it's not too much of a risk to suspend all of these procedures during a major travel holiday, then how much good are they really doing?
Cousin Dave at November 29, 2010 6:05 PM
T-shirt
Crid [CridComment at gmail] at November 29, 2010 9:50 PM
Amy, your quotes left this out:
In contrast, Radwaste actually knows what he is talking about. The absorbed dose of a body scan is so small as to be completely negligible against everything else we are routinely exposed to.
If you are truly worried about airport body scanners health effects, then you will never get another dental X-ray.
Or fly in another airliner.
---
For the record, I don't think aircrew should be exempt from body scanners. Unfortunately, ALPA neglected to ask my opinion.
---
This is the new gold standard for a non sequitur:
Hey Skipper at November 30, 2010 12:53 PM
Naw, it's directly on point. It's a wonderful new aphorism, nourished in ancient righteousness and thoughtful principle, a convenient way of looking at these matters that brings clarity to all who accept it.
Crid [CridComment at gmail] at November 30, 2010 4:59 PM
And of course the point is not what the scanner does, but that it is being used.
Radwaste at December 1, 2010 2:47 AM
My background is electrical engineering making odd measurements, worked for GE making x-ray machines years ago.
The backscatter x-ray dose is deceptively low due to how the measurement is averaged and how the particular ionization detectors used by the mfg respond to a fast moving x-ray beam. The
instantaneous dose to the skin and few cm of tissue is quite high perhaps 400-1000 x the "average" dose. The important info such as beam current needed to calculate the dose are missing from the report. Reading old patents and other docs fills in the missing info.
Also the REM dose assumes a whole body exposure of hard x-rays not applicable to soft x-ray that deliver most of the damage just a few cm deep. Soft x-rays are statically more damaging to DNA due to interaction with phosphate atoms that make up the DNA backbone. The intense soft x-ray pencil beam creates more difficult to repair double DNA breaks. One on
twenty have DNA repair issues due to a BRCA gene defect. An equal dose of random cosmic rays does not do the same damage as a bright brief collimated soft x-rays to the body. Links below have longer explanations for this subject.
search "Airport-Back-scatter-Scanner-Dose-Explained"
Warm Regards Jeff Buske
Jeff Buske at April 27, 2011 12:13 AM
Amy Alkon
http://www.advicegoddess.com/archives/2010/11/28/molecular_biolo.html#comment-2078477">comment from Jeff BuskeJeff, thanks so much for that.
Amy Alkon at April 27, 2011 12:27 AM
Leave a comment