Jesse H. said:MRI stands for MAGNETIC resonance imaging.
http://en.wikipedia.org/wiki/Magnetic_resonance_imaging -First google result, second paragraph first line.
"An MRI scanner is a device in which the patient lies within a large, powerful magnet where the magnetic field is used to align the magnetization of some atomic nuclei in the body, and radio frequency magnetic fields are applied to systematically alter the alignment of this magnetization."
The metal is ferromagnetic. The same property that makes it so that magnets can stick on metal refrigerators. Just like there is a force exerted by a magnet on a refrigerator, there is also a force exerted by a MRI system on a ferromagnetic implant. Depending on the magnitude of that force and the strength and importance of the tissue nearby, the consequences can be disasterous.pa5tabear said:Ok. So what about the metal makes it respond to a magnetic field?
A six-year-old boy undergoing an MRI examination died after the machine's powerful magnet pulled a metal oxygen tank through the air, fracturing his skull.
an MRI magnet pulled a gun out of the hand of a police officer and the gun shot a round that lodged in a wall.
Even with non-ferromagnetic materials you can get forces due to eddy currents, but I have never heard of an injury due to this. It is kind of a cool effect to see, I used to show it to tour groups. I would take an aluminum safety sign, and try to wave it back and forth through the field, etc.Q_Goest said:For non-magnetic metals such as aluminum, copper, austenitic stainless steel, titanium, etc... there is no problem with having them near an MRI.
See the link about tattoos I posted:DaleSpam said:Even with non-ferromagnetic materials you can get forces due to eddy currents, but I have never heard of an injury due to this.
identified the cause as originating in a locally induced electric current. This can, generically speaking, be induced by any metal (not just ferromagnetic metals) moving through a high-frequency magnetic field
Read More: http://www.ajronline.org/doi/full/10.2214/AJR.06.5082
Iron Man is so screwed...BruceW said:soo... the take-away message is that magneto (from the x-men franchise) is a lot more dangerous than I had previously thought? hehe
Interesting. I do a lot of work for MRI manufacturers and as long as the materials we use for the equipment we design are non-magnetic such as austenitic stainless and aluminum, we have no problem with them. Does the effect you're mentioning only apply to things that are moving? All our equipment is generally stationary (or moving slowly) when connected to the MRI.DaleSpam said:Even with non-ferromagnetic materials you can get forces due to eddy currents, but I have never heard of an injury due to this. It is kind of a cool effect to see, I used to show it to tour groups. I would take an aluminum safety sign, and try to wave it back and forth through the field, etc.
Yes, only moving metal feels this force from the main field, and even then it is only significant on large sheets of metal where the induced eddy current loops are large. That is why I always use an aluminum sign.Q_Goest said:Interesting. I do a lot of work for MRI manufacturers and as long as the materials we use for the equipment we design are non-magnetic such as austenitic stainless and aluminum, we have no problem with them. Does the effect you're mentioning only apply to things that are moving? All our equipment is generally stationary (or moving slowly) when connected to the MRI.
Metal objects are not allowed in an MRI machine because they can interfere with the powerful magnetic field generated by the machine. This can cause the metal to move or heat up, potentially causing harm to the patient and damaging the machine.
It depends on the type of metal and the strength of the MRI machine. Some metal implants, such as titanium, are considered safe for MRI scans. However, it is important to inform the MRI technician about any metal implants beforehand to ensure safety.
If a person with metal in their body goes into an MRI machine, the metal can be pulled towards the machine by the magnetic field, causing it to move or heat up. This can be dangerous and may require immediate medical attention.
It is important to remove all metal before entering an MRI machine because even small pieces of metal, such as jewelry or clothing with metal zippers, can be pulled towards the machine by the strong magnetic field. This can cause injury to the person and damage to the machine.
If you accidentally bring metal into an MRI room, you should immediately inform the MRI technician. They will advise you on the best course of action, which may include leaving the room and removing the metal object, or in some cases, rescheduling the MRI scan for another time.