We do a lot of construction work in hospitals and currently my guys have a taping knife and 2 pieces of conduit hanging from the ceiling below the floor where an MRI machine sits.
The floor is 6" concrete on a metal pan system covered by 3" inches of fireproofing material. The metal deck is permanently magnetized now, pretty impressive that it has enough power to still hold those objects with the 3" of fireproofing on it.
The floor is 6" concrete on a metal pan system covered by 3" inches of fireproofing material. The metal deck is permanently magnetized now, pretty impressive that it has enough power to still hold those objects with the 3" of fireproofing on it.
DrPizza
Administrator Elite Member Goat Whisperer
Just for what it's worth, to add something to the conversation,
Materials don't simply fall into two categories: attracted to magnets, not attracted to magnets. Some materials are repelled by magnets. This is called diamagnetism. One such material: water. I'm sure that if you look for it on youtube, you can find some videos of frogs and things being levitated by this phenomenon. And, if you run water through a strong magnetic field, you can see it deflected. Your body is mostly water.
Also, most people with metal in their bodies don't have metal that's easily magnetized. i.e. titanium alloys and stainless steel. Try sticking a kids 100% test to the stainless steel refrigerator using a magnet. You can't.
Materials don't simply fall into two categories: attracted to magnets, not attracted to magnets. Some materials are repelled by magnets. This is called diamagnetism. One such material: water. I'm sure that if you look for it on youtube, you can find some videos of frogs and things being levitated by this phenomenon. And, if you run water through a strong magnetic field, you can see it deflected. Your body is mostly water.
Also, most people with metal in their bodies don't have metal that's easily magnetized. i.e. titanium alloys and stainless steel. Try sticking a kids 100% test to the stainless steel refrigerator using a magnet. You can't.
the warning about the supermagnets on that one page selling them is terrifying. i am going to have nightmares about magnets attacking me with flying scraps of metal and wiping out all my hard drives 3 rooms over, which is worse that flying scraps of metal.
Gibsons
Lifer
- Aug 14, 2001
- 12,530
- 35
- 91
When we had our lecture on this I asked the guy this question. He said they had some veteran come in with a very small piece of magnetic material (probably some shrapnel from a mine) that they didn't know about. It didn't rip out or anything, but completely distorted their image.
StageLeft
No Lifer
- Sep 29, 2000
- 70,150
- 5
- 0
I see a lot of answers condeming you for being too stupid to know the answer and yet the people who say this don't have a fvcking clue themselves.
Anyway, a cool capital punishment would be to inject somebody with a magnetic metal in their blood, then put them in an MRI. boom!
Anyway, a cool capital punishment would be to inject somebody with a magnetic metal in their blood, then put them in an MRI. boom!
Fritzo
Lifer
- Jan 3, 2001
- 41,885
- 2,125
- 126
I was a tech about 15 years ago.
It won't get torn out of you, but it will heat up and could cause flesh/organ damage. They'll screen you before you take one. Some hospitals even have metal detectors that you have to go through before you can get into the MRI chamber.
It won't get torn out of you, but it will heat up and could cause flesh/organ damage. They'll screen you before you take one. Some hospitals even have metal detectors that you have to go through before you can get into the MRI chamber.
Jeff7
Lifer
- Jan 4, 2001
- 41,599
- 19
- 81
I used to play with strong ceramic magnets, and I'd sometimes get blood blisters from them. Then I was introduced to neodymium magnets.
When other kids were saving to buy GI Joes, I was saving to buy some neodymium magnets.I don't know what I would have done if I'd seen one of those supermagnets, like those at unitednuclear.com. A 2x2x3 block of a neodymium magnet. Good freaking god that's insane. I think I would have had the sense to never purchase one (especially given the high price), but maybe I'd have a small breakdown or something. Mine eyes hath beheld the divine magnetic field.
They'd probably have a heart attack, or some other issue, just from having the metal in their bloodstream.
They'd be dead before reaching the chamber. Still, you could always put the body in and see what happens.
StageLeft
No Lifer
- Sep 29, 2000
- 70,150
- 5
- 0
Swallowing a bunch of washers would do it, tooOriginally posted by: Jeff7
I used to play with strong ceramic magnets, and I'd sometimes get blood blisters from them. Then I was introduced to neodymium magnets.
I don't know what I would have done if I'd seen one of those supermagnets, like those at unitednuclear.com. A 2x2x3 block of a neodymium magnet. Good freaking god that's insane. I think I would have had the sense to never purchase one (especially given the high price), but maybe I'd have a small breakdown or something. Mine eyes hath beheld the divine magnetic field.
They'd probably have a heart attack, or some other issue, just from having the metal in their bloodstream.
Even let some of them partially digest.Slightly unrelated, it's in bad form to swallow rare earth magnets unless you swallow them together. Apparently if you do it at separate times and they "meet" close together by separated by bits of intestines, for instance, they can pull together and cause some nifty issues.
StageLeft
No Lifer
- Sep 29, 2000
- 70,150
- 5
- 0
jeff7 How did u get blood blisters and what do you do with the neo magnets? Neo aka rare earth are seriously criminally cheap now. You can buy, for $1.63 shipped, 20 of them from dealextreme. They're the size of a small watch battery, but thinner--more powerful than the two for $2 that one can buy at radioshack, though. I use them to hold on a canopy on an RC plane.
If you watched House, you'd know that it would get ripped right out of you and destroy the entire machine while killing hospital's main power source.
Proof: http://youtube.com/watch?v=23o_F1IOu1A
Proof: http://youtube.com/watch?v=23o_F1IOu1A
DrPizza
Administrator Elite Member Goat Whisperer
Originally posted by: Skoorb
Swallowing a bunch of washers would do it, tooOriginally posted by: Jeff7
I used to play with strong ceramic magnets, and I'd sometimes get blood blisters from them. Then I was introduced to neodymium magnets.
I don't know what I would have done if I'd seen one of those supermagnets, like those at unitednuclear.com. A 2x2x3 block of a neodymium magnet. Good freaking god that's insane. I think I would have had the sense to never purchase one (especially given the high price), but maybe I'd have a small breakdown or something. Mine eyes hath beheld the divine magnetic field.
They'd probably have a heart attack, or some other issue, just from having the metal in their bloodstream.
Slightly unrelated, it's in bad form to swallow rare earth magnets unless you swallow them together. Apparently if you do it at separate times and they "meet" close together by separated by bits of intestines, for instance, they can pull together and cause some nifty issues.
:laugh:
I used to have a ton of the neodymium magnets for use in my physics class. I successfully erased most of my credit card and debit card strips by accidentally putting them in the wrong pockets.
But, NEVER put one magnet up one side of your nose, and another magnet up the other side of your nose to give yourself that fake pierced septum look... lmao, my son had to go to the ER to have them removed.
- Oct 10, 1999
- 30,882
- 12,386
- 136
or the guy with the prison tatts screaming as they MRI'd him.Originally posted by: allisolm
LOL
That's what I was thinking. On House, a handcuff key did a lot of damage, so it must be true.
mrSHEiK124
Lifer
- Mar 6, 2004
- 11,491
- 2
- 0
They wouldn't have been able to do the bullet thing (I remember that ep :laugh
. The magnetic field in an MRI can't exactly be "shut off" so as soon as that guy's head got near it the field would have ripped the bullet right out; if that is how a bullet embedded corpse would behave in an MRI of coruse.By and large, medical implants aren't made of significantly ferro-magnetic materials. Older generations of implants were typically made from stainless steel (which despite it's iron content is not ferromagnetic - you can use a magnet to test quality cutlery - if it sticks, it's garbage grade steel).
However, in some cases, even the mild ferromagnetism of stainless steel could cause problems - the classical example being brain aneurysm clips. These sit right on a fragile artery under the brain - even minor twisting in the magnetic field of the scanner can tear the artery causing immediate death.
In the case of orthopaedic implants, they are generally screwed into bones, and even if they are mildly ferro-magnetic, they're not going to go anywhere because the bones will hold them. What they will do, however, is cause degradation of the image in the immediate vicinity.
Non-medical foreign bodies, e.g. steel shrapnel, are a bit more of a problem. By and large, if a shrapnel fragment is small (less than 1 inch) and it's deep in muscle or skin then it's probably not going to cause a problem - however, if a fragment is near a vital organ, or in the eye - then all bets are off. People who are at risk of metal splinters in the eyes (metal workers, welders, machine shop workers, etc.) should have eye X-rays before MRI to make sure that there are no metal fragments which could move and damage the retina. In the case of ferro magnetic fragments, even if it's safe for MRI because it's held in by muscles, strongly ferromagnetic materials cause very severe degradation of the image. A guy once came for MRI of a knee, but had a 1/8" steel fragment lodged in his kneecap. It wasn't going anywhere, so the techs decided to try the scan anyway. The scan simply showed a great big hole from about half way down the thigh bone to about half way down the shin bone.
More modern materials like titanium, are completely non-ferromagnetic. So they are safe against movement, and titanium in particular causes very little image degradation (e.g. the image may be distorted for only 5 mm away from the titanium).
Metal of any kind, however, may get warm or hot - this is not due to the magnetic field, but due to the powerful radiotransmitter in the scanner (average transmit power during a scan may exceed 1 kW, with peak RF outputs of over 30 kW). Because metal may act as an antenna, it may get hot, so people with significant metal work will be instructed to tell the techs if they feel any sensation of heat, so that the scan can be paused, or a less RF intensive scan mode selected. This is also the reasoning behind the problems with tattoos - despite the hype, problems with tattoos are relatively uncommon. However, heating of tattoos is easily dealt with by covering the tattoo with an icepack or wet towel.
For larger ferrous objects, projectiles are a serious hazard. There have been several deaths due to people bringing oxygen bottles, or wheelchairs, into the scanner room. Alternatively, people have been trapped pinned against the scanner by gurneys or wheelchairs. In some cases, even 6 men were unable to pull the gurney off the scanner, and the scanner's magnet had to be 'quenched' to deactivate the field (Quenching an MRI is very impressive as 150 gallons of liquid helium violently boil and you get a huge eruption of white helium mist through the emergency vents - the problem is the $10k replacement cost for the helium, $20k in charges for the manufacturer to recommission the scanner, and the cost of 1-2 weeks of downtime. This assumes that neither the impact, nor the act of quenching, damages the scanner - both can easily cause a total loss).
Some people who have brought ferrous objects into MRI rooms have been caught out because the scanners are heavily magnetically shielded - usually with active shields. This means that the field strength suddenly rises like a brick wall as you get right up to the scanner opening - this is quite unlike more familiar magnets where the strength gradually increases as you bring them closer.
However, in some cases, even the mild ferromagnetism of stainless steel could cause problems - the classical example being brain aneurysm clips. These sit right on a fragile artery under the brain - even minor twisting in the magnetic field of the scanner can tear the artery causing immediate death.
In the case of orthopaedic implants, they are generally screwed into bones, and even if they are mildly ferro-magnetic, they're not going to go anywhere because the bones will hold them. What they will do, however, is cause degradation of the image in the immediate vicinity.
Non-medical foreign bodies, e.g. steel shrapnel, are a bit more of a problem. By and large, if a shrapnel fragment is small (less than 1 inch) and it's deep in muscle or skin then it's probably not going to cause a problem - however, if a fragment is near a vital organ, or in the eye - then all bets are off. People who are at risk of metal splinters in the eyes (metal workers, welders, machine shop workers, etc.) should have eye X-rays before MRI to make sure that there are no metal fragments which could move and damage the retina. In the case of ferro magnetic fragments, even if it's safe for MRI because it's held in by muscles, strongly ferromagnetic materials cause very severe degradation of the image. A guy once came for MRI of a knee, but had a 1/8" steel fragment lodged in his kneecap. It wasn't going anywhere, so the techs decided to try the scan anyway. The scan simply showed a great big hole from about half way down the thigh bone to about half way down the shin bone.
More modern materials like titanium, are completely non-ferromagnetic. So they are safe against movement, and titanium in particular causes very little image degradation (e.g. the image may be distorted for only 5 mm away from the titanium).
Metal of any kind, however, may get warm or hot - this is not due to the magnetic field, but due to the powerful radiotransmitter in the scanner (average transmit power during a scan may exceed 1 kW, with peak RF outputs of over 30 kW). Because metal may act as an antenna, it may get hot, so people with significant metal work will be instructed to tell the techs if they feel any sensation of heat, so that the scan can be paused, or a less RF intensive scan mode selected. This is also the reasoning behind the problems with tattoos - despite the hype, problems with tattoos are relatively uncommon. However, heating of tattoos is easily dealt with by covering the tattoo with an icepack or wet towel.
For larger ferrous objects, projectiles are a serious hazard. There have been several deaths due to people bringing oxygen bottles, or wheelchairs, into the scanner room. Alternatively, people have been trapped pinned against the scanner by gurneys or wheelchairs. In some cases, even 6 men were unable to pull the gurney off the scanner, and the scanner's magnet had to be 'quenched' to deactivate the field (Quenching an MRI is very impressive as 150 gallons of liquid helium violently boil and you get a huge eruption of white helium mist through the emergency vents - the problem is the $10k replacement cost for the helium, $20k in charges for the manufacturer to recommission the scanner, and the cost of 1-2 weeks of downtime. This assumes that neither the impact, nor the act of quenching, damages the scanner - both can easily cause a total loss).
Some people who have brought ferrous objects into MRI rooms have been caught out because the scanners are heavily magnetically shielded - usually with active shields. This means that the field strength suddenly rises like a brick wall as you get right up to the scanner opening - this is quite unlike more familiar magnets where the strength gradually increases as you bring them closer.
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