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Originally Posted by mgchan
(Post 15978428)
I do not know what the laws are regarding wearing a radiation badge in the scanner. I suspect that TSA would use the excuse that it could be hiding something (same reason they make you empty your pockets of anything, not just metal). By definition the device would need to absorb some energy and thus could obscure something behind it.
I suppose it would take quite a bit of lobbying for TSA to certify some type of device, likely similar to those that are given to parents who need to hold their children for x-rays. From an individual's standpoint, it's probably just as accurate to simply find out what the radiation dose was for the examination (it should be recorded by the machine) and recording the cumulative dose. A colleague of mine helped develop an interesting iPhone app called Radiation Passport that will calculate your increased risk for cancer, cumulative radiation, etc. based on a number of activities including airport scans and medical imaging. Personally, I always opt out for the pat down. I am a radiologist and am exposed to quite high levels of radiation, though we take every precaution to limit our exposure with shielding and distance. Though I agree that the exposure to any one person is probably negligible except for the most frequent flyers (particularly given that each pass through precedes a flight that likely results in more radiation), the fact that TSA continues to use metal detectors indicates to me that there isn't enough of an advantage. On principle alone, I cannot agree with going through a screening exam that results in radiation exposure when an apparently equally good exam is available that does not use ionizing radiation. I would actually be more willing to go through the backscatter scanner if TSA stopped using metal detectors completely and told me they were inadequate, because the safety of using a superior screening examination would be worth a few micrograys of radiation. And yet, in this day of "Image Gently" and "Image Wisely" proposed by the RSNA, etc...our radiological societies are saying that *based on the info provided to them by TSA* that the scanners are ok. I don't get it. We try as hard as we can to limit dose, particularly to children. If an US will do, we don't have the pt get a CT scan. So, other than lining Chertoff's pockets, why are we using technology with ionizing radiation when we have the MMW? (privacy issues and the fact that the TSA are misguided aside) Not sure if a radiation badge would be of a lot of use...I do think the doses probably are low, though maybe not as low as they want us to think (since we still have questions about where the dose is concentrated, etc). It would probably remain in the 'negligible' level. Also, the badge could be affected by the cosmic radiation on the flight itself, skewing the data. I do locums radiology. I travel through 4-11 checkpoints a month. I won't go through the backscatter. |
Originally Posted by mgchan
(Post 15978428)
Personally, I always opt out for the pat down. I am a radiologist and am exposed to quite high levels of radiation, though we take every precaution to limit our exposure with shielding and distance. Though I agree that the exposure to any one person is probably negligible except for the most frequent flyers (particularly given that each pass through precedes a flight that likely results in more radiation), the fact that TSA continues to use metal detectors indicates to me that there isn't enough of an advantage.
On principle alone, I cannot agree with going through a screening exam that results in radiation exposure when an apparently equally good exam is available that does not use ionizing radiation. I would actually be more willing to go through the backscatter scanner if TSA stopped using metal detectors completely and told me they were inadequate, because the safety of using a superior screening examination would be worth a few micrograys of radiation. Or the use of the "Cast Scope" to take four separate exposures of someone's arm inside a cast? |
ummm.... we have people come through with them... don't know why you think we'd care... jealousy; maybe that we're not even allowed to wear ones we purchase ourselves? Granted, I don't work with AITs, but I've never heard of a ban on medical instrumentation. Then again, no one will tell me if they did external measurements at the unshielded aperture where they have TSOs standing all day or X feet away at the shielded part....
Honestly, always will opt out on the basis that everything is done in a lab dog and pony show, when I've seen how hard it is to get a cabinet x-ray system with clear damage taken out of service based off of the observations of the grunts ("It's certification is good for another 8 months, therefore, nothing could be wrong"). (next story about being asked to prove the immediate exposure risk to a lower level manager deleted) |
Originally Posted by AUS2008
(Post 15979922)
I do locums radiology. I travel through 4-11 checkpoints a month. I won't go through the backscatter.
If you do go through WBI with whatever radiation meter you desire to carry, I imagine it'll come up as an anomaly and result in a grope. |
Originally Posted by dmw650
(Post 15978059)
Haven't these scanners been tested already? Would you expect the actual emissions to be different than the specs?
Without repeating the text. Here is a wikipedia article that describes the effects. http://en.wikipedia.org/wiki/Backscatter_X-ray Also, that testing was not as in depth as the FDA would require for anything else of this type. |
And I am sure all the testing and work done on them presupposes that they have been properly maintained and serviced, which is a big maybe.
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Originally Posted by Chaos.Defined
(Post 15980195)
ummm.... we have people come through with them... don't know why you think we'd care... jealousy; maybe that we're not even allowed to wear ones we purchase ourselves? Granted, I don't work with AITs, but I've never heard of a ban on medical instrumentation. Then again, no one will tell me if they did external measurements at the unshielded aperture where they have TSOs standing all day or X feet away at the shielded part....
Honestly, always will opt out on the basis that everything is done in a lab dog and pony show, when I've seen how hard it is to get a cabinet x-ray system with clear damage taken out of service based off of the observations of the grunts ("It's certification is good for another 8 months, therefore, nothing could be wrong"). (next story about being asked to prove the immediate exposure risk to a lower level manager deleted) Hopkins wanted to test for radiation intensity outside the unit, in order to establish some sort of "keep-out" zone for screening clerks, but, could not do so without using an operational unit. The report provides interim guidance for a "keep-out" zone, pending actual testing on the real thing: 4' at either side 6' to the rear 13' above Statistically speaking, a whole lot of screening clerks are going to become very sick some day. |
Originally Posted by dmw650
(Post 15978059)
Haven't these scanners been tested already? Would you expect the actual emissions to be different than the specs?
What regular testing takes place? Who performs this testing? Why haven't these machines been fully tested like the medical devices that they are? I know of at least one system - the Therac-25 one of the first systems surveys we completed when I was studying computer science - that jumped through all the hoops we require for medical devices but still managed to harm a number of people. Can these devices also harm people? I don't know for certain, but I will be happy to let someone else find out. |
I am glad you mentioned the Therac-25, that saves me the trouble of looking up the reference in reply to dwm650. :) And it's not the only such story.
Sure, the backscatter boxes are probably safe... but it sure would be nice if that could be better illustrated. Mistakes happen. Negligence happens. Machines break. Let's not just hope for the best. Let's not just trust. They put more warnings on a bottle of beer than the backscatter checkpoints. Accurate dosage information should be mandatory as should a transparent maintenance schedule. Exposure adds up. It matters. The keep-out zone info is REALLY interesting. |
Originally Posted by horseflesh
(Post 15981874)
Exposure adds up. It matters.
The backscatter scanner shows shinbones. Do you really think your scrotum is thicker than the skin over your shinbones? |
Accidents can and do happen, even in hospitals.
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In my experience, children are most often allowed to bypass the backscatter machines (and usually at least one adult who is with them!).
So how do we prevent the next underpants bomber if we get rid of these altogether? |
Originally Posted by RobertS975
(Post 15982262)
In my experience, children are most often allowed to bypass the backscatter machines (and usually at least one adult who is with them!).
So how do we prevent the next underpants bomber if we get rid of these altogether? How will we prevent the next rectal suppository bomber? How will we prevent the next FRA shooter who's outside the current security perimeter? The answer IMHO lies in intelligence gathering, police work, and a reasonable degree of security. Life is uncertain at best. |
Originally Posted by Caradoc
(Post 15980145)
So what would your opinion be on the reports coming in that some people have been put through the backscatter scanners repeatedly as the dolts in blue shirts try to interpret the images?
Or the use of the "Cast Scope" to take four separate exposures of someone's arm inside a cast? Would I subject myself to the radiation if they told me they could guarantee my safety? Sure; it's a very worthwhile risk. But just as I refuse chest X-rays when the doctors can't tell me what they expect to find (or as another poster mentioned, would choose an ultrasound or MRI over a CT if they were equally effective), I don't see why I should go through a backscatter device rather than a metal detector or pat-down if they are apparently just as effective. |
Originally Posted by FliesWay2Much
(Post 15981274)
I suggest you read the Hopkins report. The contractor, Chertoff, Inc., would not allow Hopkins to test a production unit and the TSA let Chertoff get away with it. So, they had to test a unit put together from spare parts and prototype units.
Hopkins wanted to test for radiation intensity outside the unit, in order to establish some sort of "keep-out" zone for screening clerks, but, could not do so without using an operational unit. The report provides interim guidance for a "keep-out" zone, pending actual testing on the real thing: 4' at either side 6' to the rear 13' above Statistically speaking, a whole lot of screening clerks are going to become very sick some day. |
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