DHS X-ray Car Scanners Now At Border Crossings 295
OverTheGeicoE writes "CNET has a story on DHS' whole car X-ray scanners and their potential cancer risks. The story focuses on the Z Portal scanner, which appears to be a stationary version of the older Z Backscatter Vans. The story provides interesting pictures of the device and the images it produces, but it also raises important questions about the devices' cancer risks. The average energy of the X-ray beam used is three times that used in a CT scan, which could be big trouble for vehicle passengers and drivers should a vehicle stop in mid-scan. Some studies show the risk for cancer from CT scans can be quite high. Worse still, the DHS estimates of the Z Portal's radiation dosage are likely to be several orders of magnitude too low. 'Society will pay a huge price in cancer because of this,' according to one scientist."
Re:The CT Scan Claim from TFA (Score:5, Informative)
"One of the studies, which examined more than 1,000 adult patients at four hospitals, projected that the dose of radiation received in a single heart scan at age 40 would later result in cancer in 1 in 270 women and 1 in 600 men.
To be fair, heart scans are the high mark for radiation dosage. Since you need to look at how the heart actually moves/cycles it take much longer to image compared to other parts of the body. There are also many different CT scanners. Some of the high slice scanners reduce the dosage considerably. The Toshiba and Philips 320/256 slice scanners can image the heart in a single rotation rather than continual helical rotations. There are also several new algorithms that use lower dosages with a worse s/n ratio then clean it up in post processing. Regardless, I don't expect DHS/TSA to concern themselves with proper radiation procedures, nor the same scrutiny towards calibration as medical devices.
Re:I don't think it's X-Rays (Score:5, Informative)
Everyone knows X-Rays can't penetrate metal.
So that my job in xraying metal is fake?
http://www.vidisco.com/NDTInspection.asp [vidisco.com]
These xrays are much more powerful (intensity and energy) than medical xrays.
I know someone that walked in front of one of these running machines a few decades ago (by accident, of course). He sufferred accute radiation poisoning that required almost 2 weeks to recover. Day after exposure, he almost could not walk.
Still, there is SOME kind of scanner technology that they DO use to inspect the cargo of 18-wheelers without emptying out the load. But it's NOT X-Rays.
Keep repeating after me. Ignorance is bliss. Ignorance is bliss. Ignorance is BLISS!
Re:I don't think it's X-Rays (Score:3, Informative)
It is far too simplistic to say that "X-Rays can't penetrate metal."
X-rays are absorbed by a material by interacting with the electrons around the nucleus (or with the nucleus itself). This is a statistical question - X-rays will penetrate a short distance into a material. the more dense the material or higher energy (frequency) of the X=rays, the less they will penetrate. See for example
here [ndt-ed.org].
There is a table at the bottom of penetration depths through lead as a function of energy of the X-rays.
Re:I don't think it's X-Rays (Score:5, Informative)
Funny, then, that my research focuses on the behavior of X-rays through metals. X-rays can penetrate metals, depending on the energy of the radiation used. high-energy radiation passes through almost everything, and interacts only a little with intermediate objects. Hence, it is very well possible they are using X-rays for this, but they can pretty much only use it to visualize the internal metallic structure of objects as it will pass right through people.
Re:I don't think it's X-Rays (Score:5, Informative)
http://www.forbes.com/sites/andygreenberg/2011/03/02/docs-reveal-tsa-plan-to-body-scan-pedestrians-train-passengers/ [forbes.com]
e.g. "drive-by" mode and covert screening from vans http://www.as-e.com/zbv/ [as-e.com]
http://epic.org/privacy/body_scanners/Body_Scan_FOIA_Docs_Feb_2011.pdf [epic.org]
They build up a 3d like view of metal vehicles. You would think every person in the area would get into shielded rooms (control and guarded waiting room) as the vehicle in question was scanned.
I guess radiation is now 100% safe in the USA.
Re:This will definitely increase cancer risks (Score:2, Informative)
Did you even read the summary, let alone the article, or at least look at the pictures? You are supposed to drive through the thing.
Re:I don't think it's X-Rays (Score:5, Informative)
Same AC. Just wanted to clarify due to the present "Score:4, Funny", that I'm completely serious. They contacted me in 2006 for this project, since I have both a programming and physics background. Once I learned more, I told them to stuff it.
"High energy" misleading (Score:5, Informative)
The average energy of the X-ray beam used is three times that used in a CT scan
This may or may not be a misleading statement. There's inadequate context and specificity in the article. "Energy" here could refer to the total amount of ionizing radiation energy delivered to a person in the scanner, in which case these portal scanners could be considered extremely dangerous, since a typical CT is already a substantial and potentially dangerous radiation dose. Alternatively, the word "energy" may refer to the energy of the individual x-ray photons. In other words, if a typical CT uses 100keV x-rays and these scanners use 300keV. That is probably what was meant. It's clinically meaningless. Within reasonable ranges of several tens of keV to several MeV, only the total absorbed dose really matters health-wise, not the energies of the individual particles.
With that said, I still don't condone this type of intrusive inspection - even at the border.
They have been doing this for months (Score:2, Informative)
First, I haven't read TFA but, I live 5 min form a us Canada border crossing. They have been doing this for months now. When they scan the vehicles they have the occupants exit the vehicle and stand in a "safe area" over 100 ft away from the truck doing the scanning.
Re:"High energy" misleading (Score:5, Informative)
It's almost certainly the latter. You need higher energy X-rays to penetrate metal and "energy" is almost never used to refer to intensity, much less dose.
Re:What if you don't consent? (Score:5, Informative)
If you do raise your voice or object, they will charge you with a blanket offense like "insulting a federal officer" or "terrorist threats." Don't laugh - an unarmed transgender [youtube.com] with both arms in the air was tazed in the crotch by the BLM pigs. S/he was later charged with "terrorist threats."
Anyway, if you're clean, you will be released eventually, put on a watch-list, and harassed everywhere you go. God bless America.
Re:This will definitely increase cancer risks (Score:2, Informative)
"A car containing 10 kilos of weed contains nearly 8 kilos of weed, meaning that not only will someone go to jail for possessing 5 kilos of weed
What in hell have you been smoking?
The fail hurts.
It's a joke that the dealer had 10kg of weed, then the cops who pulled him over skimmed off 2kg (leaving 8kg). When that was delivered to the evidence lockup, the cops running that skimmed another 3kg off (leaving 5kg) which is used as evidence. The skimmed weed is then used by the cops or dealt out on the street (cops who deal primarily with drugs and cash tend to annoyingly crooked [youtube.com]).
X-Rays same as Gamma rays (Score:5, Informative)
Gamma radiation I could see, but X-Rays have a GREAT deal of difficulty penetrating metal.
There is no real distinction between X-rays and Gamma rays in terms of their properties. They are named based on how they were produced and their application. Create them by accelerating electrons into a metal target in a hospital and you call them X-rays. Create them in nuclear or particle decays and they are called gamma rays. In fact if you create them by smashing high energy electrons into a metal target in a particle physics lab we'll call them gamma rays as well.
As for penetrating metal we make calorimeters designed to measure photon energies which consist of plates of dense metal - like lead, depleted uranium etc. As the photon penetrates these metal sheets it makes a shower of particles and we count the particles in the gaps between the metal plates. Such detectors are usually metres thick for GeV photon energies (probably at least 1,000 times higher than what these machines use - I hope!). But the point should be clear - give a photon enough energy and it penetrates lead and depleted uranium - so the thin sheet metal in a car is not an issue. However I'd not want to be driving a car which is being subjected to that.
Re:This will definitely increase cancer risks (Score:4, Informative)
Not only that but regular medical X-rays already have a history of accidental radiation poisoning, poisoning several hundreds of patients over several weeks (until the cause was found because the radiation poisoning was a) localized and b) easily traced because everyone had access to decent health care and knew they were scanned at some point) because a single variable was off in a program or badly set by a technician.
A single x-ray machine can do maybe 40 people a day given a 24 hour cycle. This thing will probably do 40 people every 15 minutes and has a much higher dosage by default. One or more of these things will not only kill people but it will also kill the workers and the cause won't be as easily found because cases will appear seemingly independently all over the world and in 3rd world countries (such as Mexico or people traveling internationally) so cases won't be as easily linked, people won't know they've been scanned by these things and many will die before the one is found out and then they'll only claim 1 faulty machine, implement some 'safeguards' and make empty promises but continue doing it until the next machine fails.
Re:The CT Scan Claim from TFA (Score:4, Informative)
Funny, but this really more a drug war thing. Glenn Greenwald recently debated Bush's drug czar on the drug war, and buried him. Just ground him into the dirt.
http://vimeo.com/32110912 [vimeo.com]
Re:Why? (Score:4, Informative)
Why use horribly expensive technology when cheap alternatives are available
Because horribly expensive technology funds companies who fund lobbyists who fund congressmen.
Re:I don't think it's X-Rays (Score:5, Informative)
Since they're only following orders.
The worst crimes in the history of humanity were carried out by people who were just following orders.
People following orders are still morally culpable for their acts.
Re:I don't think it's X-Rays (Score:4, Informative)
Since they're only following orders.
The worst crimes in the history of humanity were carried out by people who were just following orders.
People following orders are still morally culpable for their acts.
Actually, I think most of us picked up that is what the GP was already implying by his humorous 5 word interjection, but please, don't let me interrupt your needless exposition. ;-)