ElizabethConley

http://www.reuters.com/article/2011/...72R6ER20110328

Does anybody know if the good doctor actually ran tests on TSA equipment in order to get her data?

'Cause otherwise, I call Bravo Sierra.

AUS2008

Well, that certainly contradicts the conclusions drawn by Dr. Brenner of Columbia University, who recently testified before the Congressional subcommitee, and published his findings in the April 2011 issue of Radiology.

I tried to link it last week when the article came out, but it is a password restricted journal site. Below I have cut and pasted some of it (not sure what all the copyright rules are). Like Dr. Brenner said in Washington 2 weeks ago....the estimated dose to ONE person getting ONE scan is low, and the cancer risks related to that would be low. But if you multiply the very small risk either by large numbers of people flying (est. up to 1 billion pax/year), then the risk is proportionally greater. Or, if you multiply the very small risk to an individual being scanned numerous times, such as flight crews, FFs, and yes, even the TSA who is unwise enough to stand right next to the entry to the scanner for multiple scans in a shift, then the risk is greater.

Also...with regard to radiation dose (excluding privacy issues for this discussion), there is an option which does not emit ionizing radiation --the MMW. So the radiation from backscatter is not necessary (much as a physician/radiologist would use ultrasound to make a diagnosis, when appropriate, rather than a CT).

Are airport whole-body x-ray backscatter
scanners safe? In brief, yes and
no. I will argue here that, in terms of individual
risk, the radiation doses associated
with whole-body x-ray backscatter
scans are suffi ciently low that it is reasonable
to characterize them as “safe” (ie,
representing at most an extremely small
cancer risk) for most individuals who
travel only a few times each year. Potential
risks will be higher for high-level
frequent fl iers and fl ight personnel, however.
Perhaps more importantly, from a
public health policy perspective, given
that up to 1 billion such scans per year
are now possible in the United States, we
should have concerns about the longterm
consequences of an extremely large
number of people all being exposed to a
likely extremely small radiation-induced
cancer risk—in particular given that
there are current practical alternatives
that do not involve ionizing radiation.

...
...

One could perhaps debate whether
this “safe” descriptor should apply to
scanning children, for whom the cancer
risks are probably 5–10 times higher
than those for subjects in middle age
( 29,36 ); radiosensitive individuals, including
the developing embryo and fetus;
or fl ight personnel and high-level frequent
fl iers. For example, a domestic
flight attendant or pilot in the United
States passes through security in the
range of 240–380 times per year (Laura
Cox, written communication, October
2010), which would result in a potential
effective dose from x-ray backscatter
scanning of about 300 m Sv per year. Likewise,
a high-level frequent fl ier averages
more than 200 fl ights per year ( 37 ) and,
thus, could receive an annual effective
dose of 200 m Sv from x-ray backscatter
scans. The corresponding best-estimate
fatal cancer risks in these cases would
be about 10 2 5 per year, which is larger
than the NCRP NIRL of 10 2 7 .

...
...

screening, there are two
relevant consequences of ALARA:
1. Comparisons with other risks are
not necessarily relevant. The fact that
fl ying involves other radiation exposures
or other different risks is not relevant
to the ALARA requirement to minimize
the ionization radiation exposure associated
with practical passenger screening.
In another context, for example, one
would not ignore the radiation exposures
associated with computed tomographic
scans simply because domestic radon
exposure involves larger effective doses.
2. If there is a nonionizing radiation
alternative that can reasonably achieve
the same screening goal, then, in keeping
with the ALARA principle, it should
be used in preference to an x-ray–related
technology. As far as is known, millimeterwave
whole-body scanning technology
fulfi lls this requirement. In terms of specifi
city, sensitivity, cost, and speed, the
millimeter-wave technology is generally
comparable to the x-ray backscatter
technology ( 3,6 )

Lara21

It is highly doubtful she did since some of the agencies they claim tested the machines that they claimed proved they were safe to be actually used on airline passengers. Those agencies came out and said they weren't allowed to test a real machine. But one they pieced together. Her data was gotten from a pieced together machine.

FliesWay2Much

Wow, the good doctor really quantified the issue. I never would have made it out of freshman physics if I submitted a lab report with my data quantified as "super low" or "really high."

Sorry, Pissy, that's six too many.

Sorry, Pissy, that's four too many. Besides, what is an "extra cancer?"

Sorry, Pissy, that's one too many.

Tell us, Pissy: How many "extra cancers" for your clerks are OK?

The deans and faculty of UCSF should be embarrassed by this report. Comparing highly correlated and focused radiation precisely focused on the skin to toxic iodine isotopes and plutonium released in a nuclear accident is laughable. This is like comparing a laser to a tanning bed.

It would be interesting to follow the money. Betcha' a Diet Coke that this study was funded by either a TSA grant or an industrial grant from Chertoff, Inc.

WillR

That's a low criticism. It's perfectly reasonable to use everyday words for clarity when describing scientific phenomena. The actual figures are included in the text of the paper.

And I'm pretty sure you can guess what an 'extra cancer' is. It's the excess in cancer diagnoses with an intervention as compared with a theoretical or actual control group.

tkey75

Anything for security. Cancer not excluded apparently.

FliesWay2Much

Sorry, the good doctor is a radiology professor and she should talk like one. Perhaps you misunderstood me. Any cancer illness and/or death directly caused by the Government of the United States of America is completely 100% unacceptable.

AUS2008

Dr. Brenner said in his testimony that there could be 100 cancers caused by the scanners/year, if all of the est. 1 billion pax/yr were scanned. But there are still questions out there about what the actualy dose and risk are, since the numbers are not exactly reliable and the feds have admitted mistakes in the earlier reported dose/exposure data.

WillR

I think once you've proved your credentials (eg by becoming a professor) it's ok not to have to prove it every day by using jargon.

Eg I'm an MD, but I still say things like 'he looks pretty sick' or 'this sodium is really high'. I don't have to say 'this is moderate hypernatraemia, with the sodium being 153mEq'

Travelsonic

I agree to an EXTENT - in some cases it is really not a big deal, but strictly IMO when it comes to something like radiation, I am not sure if terms like "super high," or "super low" so far as quantities relevant to exposure are anything but arbitrary, and unclear / undefined terms that could mean anything without some degree of precision - further obfuscating the facts.

FliesWay2Much

Yes -- and there's a huge difference when you're speaking on the record versus 1-1 to a patient. I would expect this kind of quote from Spokesholess-in-Chief Kristin Lee.

AUS2008

I'll agree with this....I even accidentally used the (not a) word "ginormous" at work one day.
BUT...this article is quite one-sided, and still contradicts some of the concerns brought up by other radiologists and radiation physicists/biologists.

As a radiologist myself, the backscatter is in violation of the ALARA principle, since there is an alternative that does not use radiation --the MMW. It is still extra radiation, and is preventable. Her numbers vary from Dr. Brenner's as well, though Dr. Brenner does qualify his, indicating that there are plenty of unknown factors to truly guesstimate the impact.

I also hate that she makes it seem as if it is ok for kids to go through these, even though kids are more susceptible to radiation effects.

Also....I wonder if this is even a valid comparison---the scanners to a nuclear event. That's like saying the chances of your dying getting run over by a Hot Wheels car are super low compared to getting run over by an 18-wheeler.

flyless

Being a professor or MD doesn't give you instant credibility. How many PhDs and MDs in the FDA and other organizations approved of, and lauded, only to find years later that it was a significant contributor to cancer in women? How many PhDs and MDs approved other drugs such as Reglan or Vioxx only to find out years later that the side effects could be severe and debilitating?

I would argue just the opposite, which is that they have less credibility because they are stuck in their ivory towers and don't really see the real world.

WillR

I think you get at least an assumption of credibility, although rebuttable. My point is that using jargon does not add to your credibility. Obviously language should be accurate, but general terms can be accurate if not precise, and depending on context precision is variably required. I'm usually happy with reports of radiation expressed to 2 significant figures, for example, and even 1 is acceptable sometimes. 0.1mSv for a chest film is perfectly accurate insofar as what it says, even if it is imprecise because the actual value is 1.0422313x10^-4 Sv in a particular case.

Hmm. This says more about you than anything else. Lots of professors have no towers, ivory or otherwise.

WillR

To clarify - the ^ in my post above is obviously meant to be a caret, not a thumbs-up.