[ RadSafe ] Backscatter x-ray

Doug Aitken jdaitken at sugar-land.oilfield.slb.com
Thu Nov 18 13:57:41 CST 2010


Cory: It may be that no screening method will be 100% (other than a full CAT
scan?), but all of these are probably seen more as deterrents to people
attempting to pass nasty stuff, rather than effective detection
techniques..... (which is kinda sad, considering the amount of money
spent.... - but then, when was the whole "homeland security" paranoia not
seen as a business opportunity by both the government agencies and the
companies developing the technology.....).

And, of course, it is the innocent passengers who suffer the
consequences......

Someone commented on the Israeli approach of competent humans performing the
screening (which of course involves a degree of "profiling" which is
anathema to many in the US). It is evidently effective. However, their
problem is much more limited: they really only do this for El Al flights, so
it is a manageable process.

Regards

Doug Aitken
QHSE Advisor, Schlumberger D&M Operations Support
Cell Phone: 713-562-8585
(alternate e-mail: doug.aitken at slb.com )
Mail: c/o Therese Wigzell,
Schlumberger,
Drilling & Measurements HQ,
300 Schlumberger Drive, MD15,
Sugar Land, Texas 77478



-----Original Message-----
From: radsafe-bounces at health.phys.iit.edu
[mailto:radsafe-bounces at health.phys.iit.edu] On Behalf Of Cary Renquist
Sent: Thursday, November 18, 2010 1:35 PM
To: The International Radiation Protection (Health Physics) MailingList
Subject: Re: [ RadSafe ] Backscatter x-ray


I don't necessarily mind if I have to do a scan and I'm not concerned about
the dose, but...  
As radiation professionals, we have a mandate to minimize unnecessary
(useless) radiation exposure -- some states even have explicit regulations
that that only permit human x-ray exposure under a doctor's orders.

The backscatter x-ray system is theater.  (might as well just use one of
those sony camcorders that was missing the IR filter)

I'm sure that I could stick the same amount of explosive that Reid had in
his shoe between my butt-cheeks (yes I went there).  If I start visiting the
new Cuban bakery down the street as often as I would like to, then in a year
or so I will have a lot more rolls and folds to use...  

I seem to recall that the mm-wave scanners can at least see a bit through
rolls and folds.

If they want to do something effective and still spend lots-o-money,
then they should just conduct pat-downs with ultrasound wands.   

Cary

---
Cary Renquist
cary.renquist at ezag.com


-----Original Message-----
From: radsafe-bounces at health.phys.iit.edu
[mailto:radsafe-bounces at health.phys.iit.edu] On Behalf Of Miller, Mark L
Sent: Thursday, 18 November 2010 10:42
To: 'The International Radiation Protection (Health Physics) Mailing List'
Subject: [ RadSafe ] Backscatter x-ray

IMHO, it seems that we radiation protection professionals are missing a
great teaching moment here.  This is because: 1) the dose from the scanning
machines in 100s of times less than the radiation dose that flyers will get.
Therefore, if radiation exposure is their concern, they should deal with the
FACTS.  If their issue is "invasion of privacy", I have little sympathy for
their position.  If they want the convenience of travel by air, then they
must comply with the steps TSA has taken to protect EVERYONE's safety from
"terrorists" (or walk).
This brings me to 2): TSA didn't invent the problems posed by protecting
travelers from terrorists.  The terrorists did!  Irate travelers should
direct their anger to those truly responsible for it (good luck).  And
finally, 3): perhaps the Israeli approach to passenger screening is
superior. The billions spent worldwide on really neat equipment may not be
nearly effective as really smart personnel screeners.

-----Original Message-----
From: Brennan, Mike (DOH) [mailto:Mike.Brennan at DOH.WA.GOV]
Sent: Thursday, November 18, 2010 10:07 AM
To: The International Radiation Protection (Health Physics) MailingList
Subject: Re: [ RadSafe ] bakscatter x-ray

If I were a bad guy trying to sneak something past TSA, one of the things I
might do is have confederates, preferably people who didn't even know there
was something real going down, hassled the screeners to distract them.  If I
were some TSA games theory guy, I would recognize the bad guys might do
this, I might encourage a policy of screener being extra thorough with
people who were intentionally complicating the process, as a way of
dissuading the behavior.  On those rare occasions that I have interacted
with the police, I have found that respect and cooperation have kept those
interactions short and less painful than they might been.  

I like Lewis Black's take on it; "You mean I get to fly from New York to Los
Angeles in six hour AND someone fondles me?  Is this a great country, or
what!  I'm glad that TSA hasn't thought to change me a baggage handling
fee."

-----Original Message-----
From: radsafe-bounces at health.phys.iit.edu
[mailto:radsafe-bounces at health.phys.iit.edu] On Behalf Of Jeff Terry
Sent: Wednesday, November 17, 2010 6:09 PM
To: The International Radiation Protection (Health Physics) Mailing List
Subject: Re: [ RadSafe ] bakscatter x-ray

I am already working on that today. We are x-raying pepto bismo to see if we
can recommend painting everyone's underwear pink. Should work as a temporary
tattoo as well without needing to dip into lab chemicals. It is always
better to screw with TSA with over the counter products.  

The ultra strength has over 500 mg of Bi subsalicylate per 15 ml. 

Our other suggestion is going to be to wear an athletic cup, a 1/4 inch of
ABS plastic should let you walk through the metal detectors, yet still play
havoc with the backscatter machines. 

I think that our measurements are looking good. We will be preparing our
website for recommendations shortly.

No concern on our part about the radiation, just the civil liberties. 

Jeff

Jeff Terry
Asst. Professor of Physics
Life Science Bldg Rm 166
Illinois Institute of Technology
3101 S. Dearborn St. 
Chicago IL 60616
630-252-9708
terryj at iit.edu




On Nov 17, 2010, at 7:56 PM, Cary Renquist wrote:

> 
> I took a quick look at one of the papers that they cite for dose per 
> scan data... The paper was by some researchers at John Hopkins U.
> 
> (Been a long time since I have played with x-rays and I have never
dealt
> with 50 kVp x-rays)
> Their list of equipment for dose measurement was a large ion chamber
> (1800 cm^3 volume) and a Thermo Sci. (Bicron) micro-rem survey meter.
> Neither of those seem especially appropriate for rigorously 
> characterizing the dose from such a low energy x-ray source.
> Particularly where the concern might be entrance dose.
> 
> As I indicated above, I took a really quick look -- haven't read the 
> experimental protocol/analysis or any of the other papers that are 
> available.
> They can be downloaded from the TSA site: TSA Electronic reading room 
> http://j.mp/92qzyT
> 
> Probably a good read for my flight back home for Thanksgiving...
> (perhaps I should grab some heavy metal carrier solution from the lab
> (bismuth?/barium?) and paint a smiley face on my skin)
> 
> Best regards,
> Cary
> 
> ---
> Cary Renquist
> cary.renquist at ezag.com
> 
> 
> -----Original Message-----
> From: radsafe-bounces at health.phys.iit.edu
> [mailto:radsafe-bounces at health.phys.iit.edu] On Behalf Of Brennan,
Mike
> (DOH)
> Sent: Tuesday, 16 November 2010 08:53
> To: radsafe at health.phys.iit.edu
> Subject: Re: [ RadSafe ] bakscatter x-ray
> 
> X-ray isn't my corner of the rad world, but the more I think about the
"
> The majority of their energy is delivered to the skin and the
underlying
> tissue. Thus, while the dose would be safe if it were distributed 
> throughout the volume of the entire body, the dose to the skin may be 
> dangerously high." Statement, the less sense it makes to me.  It seems 
> to me that for any x-ray the majority of the absorption is in first 
> dense material it encounters; the skin.  It also seems to me that if
one
> set up detectors to collect and process the backscatter from a 
> diagnostic x-ray procedure, you could image the target's skin through 
> their clothing (though this would be far more difficult than just
asking
> them to take it off).  Unless someone can point out where I am wrong 
> (and I well might be), it seems that this objection is without merit.

> 
> -----Original Message-----
> From: radsafe-bounces at health.phys.iit.edu
> [mailto:radsafe-bounces at health.phys.iit.edu] On Behalf Of Brennan,
Mike
> (DOH)
> Sent: Monday, November 15, 2010 4:05 PM
> To: radsafe at health.phys.iit.edu
> Subject: Re: [ RadSafe ] bakscatter xray
> 
> If the majority of the energy is delivered to the skin, then wouldn't
it
> follow that the majority of THAT energy is delivered to the outer
layer
> or the skin; the layer of dead skin cells?  If the claim is that the 
> radiation penetrates the dead layer, but is then deposited in the
living
> tissue, I would think that there should be some support for that.  
> 
> 
> -----Original Message-----
> From: radsafe-bounces at health.phys.iit.edu
> [mailto:radsafe-bounces at health.phys.iit.edu] On Behalf Of conrad
sherman
> Sent: Sunday, November 14, 2010 6:57 PM
> To: radsafe at health.phys.iit.edu
> Subject: [ RadSafe ] bakscatter xray
> 
> here is the letter from ucsf and response
> 
> LETTER OF CONCERN
> 
> ...Snip.....
> 
> (28keV).The majority of their energy is delivered to the skin and the 
> Underlying tissue. Thus, while the dose would be safe if it were 
> distributed throughout the volume of the entire body, the dose to the 
> skin may be dangerously high.
> 
> ....Snip....
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