[ RadSafe ] Backscatter x-ray

Thu Nov 18 13:35:01 CST 2010

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....