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Spud guns, PVC, X-rays, and emergency rooms...
Posted: Wed Dec 16, 2009 1:49 am
by D_Hall
Those who've read this forum for some time are familar with the conventional wisdom associated with PVC and emergency rooms. For those not familiar, it goes something like this... PVC is bad juju if a gun ever grenades on you. The problem is that PVC is similar in density to flesh and as such it won't show up on X-rays at the emergency room. Thus, it's tough for medical types to make sure that they got all those lovely fragments out of your flesh. This makes for complications, blah blah blah....
At the office, the guy three cubicals down from me is a level 3 radiographer. We were talking today and the topic of spud guns made from PVC came up and I thought of the question regarding PVC visibility in X-rays. I asked him about it.
His opinion? With modern X-ray equipment, PVC would be trivial to see in X-rays.
HOWEVER.... To end the discussion once and for all I asked him if I could bring in a couple steaks and some PVC pieces. The idea being that I would sandwich the PVC between two slabs of meat and see if he could image them. He said it would be no big deal. When he starts a new test series he has to run some calibration shots and he could just throw the meat into one of those at no cost to anybody (other than me for bringing in the steaks).
Stay tuned!
Posted: Wed Dec 16, 2009 2:05 am
by McCoytheGreater
Finally. Someone actually debunking the "PVC X-Ray Myth". There are a number of tests besides X-ray that would make the PVC shards show up. I still wouldn't want one to fragment in my side, though. that wouldn't be fun.
Posted: Wed Dec 16, 2009 3:44 am
by CS
Posted: Wed Dec 16, 2009 3:58 am
by bradisfun
awsome!
i thought that this woud be the case
hey i should try this out my self as i hav acses to a x-ray machine
Posted: Wed Dec 16, 2009 7:12 am
by kenbo0422
Oh, for a moment there I thought those were Xrays of the actual hip and bone replacements...
I want mine in Schedule 160.
Posted: Wed Dec 16, 2009 7:36 am
by psycix
Way to go, mythbuster!
I recommend you to smack a PVC pipe into shards and put the shards between it.
Heck, with your job, you could blow PVC up for real shrapnel and put that in!
Posted: Wed Dec 16, 2009 7:54 am
by jackssmirkingrevenge
psycix wrote:Heck, with your job, you could blow PVC up for real shrapnel and put that in!
*please*

Posted: Wed Dec 16, 2009 10:02 am
by McCoytheGreater
I want mine in Schedule 160.
Hell, I'd need mine Schedule 160.
Posted: Wed Dec 16, 2009 10:47 am
by D_Hall
psycix wrote:I recommend you to smack a PVC pipe into shards and put the shards between it.
One would absolutely HAVE to do that. The primary purpose of X-rays in my line of work is the sensing of voids (ie, air pockets) in materials. To have an intact pipe in the mix (as shown in the linked pic earlier in this thread) introduces voids. Those voids will be easy to see on the film.
Thus, to do the test as it ought to be done, one needs flat pieces of PVC that will not create voids.
Although I will say that based on the pics linked earlier I'm not sure anything more needs to be done. The increased density is clearly visible.
Posted: Wed Dec 16, 2009 2:46 pm
by psycix
Since it is based on density, Id like you to try both normal PVC and cellular core. Maybe you could also try ABS while you're on it anyway.
D_Hall wrote:Although I will say that based on the pics linked earlier I'm not sure anything more needs to be done. The increased density is clearly visible.
Its only visible in the parts where the walls are parallel with the angle of view. The flat (perpendicular) pieces of pvc are hardly visible. (and the rays have to go through TWO wall thicknesses!)
This would mean that for optimal PVC shrapnel detection, you will need to make multiple X-ray snaps from different angles, as the shards will be invisible when the shard is perpendicular with the angle of view and clearly visible when its pointed straight toward the cam.
Posted: Wed Dec 16, 2009 3:10 pm
by CS
Lucas_Pukas wrote:I was a Radiology Technician for an internship for a couple years. PVC will more than likely show up (havent personally seen it). It won't be as defined as say metal or bone, it will be fuzzy and gray. Doctor's diagnose pneumonia with x-rays...because the fluid in your lungs is more dense than the lungs thenselves. The same goes for PVC. It is more dense than say skin, fat, muscle etc so it will "absorb" more of the radiation. Similar concept is used in radar, but the waves bounce back to the cop...rather than shooting through the body and being absorbed on the x-ray film.
Seems fair to conclude a shard could be detected by similar equipment. Also not of the field, but x-ray can be adjusted. Looking at dental x-rays seems the magnitude of delineation is great enough to detect any foreign object, especially to someone of the medical community.
Posted: Thu Dec 17, 2009 1:10 am
by McCoytheGreater
Just today as I way buying pipe for my next combustion-esque gun, someone told me that PVC wouldn't show up in X-rays so be careful. Silly redneck.