Chair gets stuck in an MRI machine
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Stumble ThisMetal chair + proximity to powerful MRI = Chair stuck inside MRI
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chair,mri,magnet Chair gets stuck in an MRI machine
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Turn the MRI off maybe ?
Except that it's a magnet. You can't turn off magnets..
>> ^charliem:
Turn the MRI off maybe ?
Except that it's a magnet. You can't turn off magnets..
Are you for real ?
Edit: Also, cant believe someone upvoted that. The collective IQ of VS just dropped 20 points.
The magnetic field and the associated risk of missile-effect accidents remains a permanent hazard — as superconductive MRI magnets retain their magnetic field, even in the event of a power outage.
Looks like it doesn't turn off even when turned off.
Charliem: You can turn off electro magnets. And even then certain types will remain magnetic. You can't turn off a magnet.
Simply not true.
The only electo-magnets that "retain" their fields after being switched off, are super-conductive rare-earth elements that have been super-cooled to very low kelvin temperatures.
When the material is bought back up past its super-conductive threshold, it loses its magnetic field.
Every electro magnet that can be switched off, loses its magnetic properties.
MRI's rarely use permanent magnets, as the resolution of a perm magnet is so low, and the materials required to produce a field strong enough for a clear picture, are immensely expensive, and heavy.
Theres a pretty decent chance this is an EM MRI, all they needed to do was let the thing warm up a bit after using it (generally by turning the cooling pumps off).
[further stipulate how much smarter I am.]
[include derisive comments toward other commenters.]
[ego inflation +1]
also, the junk in your neck does indeed produce some righteous artifact.... like its pretty pointless to ever get a CT scan of your neck.
i dont understand how that chair got anywhere near the MRI in the first place. everywhere ive ever worked has had specialty items for MRI. special chairs, stretchers, wheelchairs, oxygen tanks, etc. and the room where the techs sit their butts is not the room where the patients are scanned. wierd.
>> ^charliem:
Turn the MRI off maybe ?
Except that it's a magnet. You can't turn off magnets..
Thing is, it's an electromagnet.
To clear things up, clinical MRI's use Superconducting Electromagnets. After installation, the current is slowly ramped up until the desired field strength is reached but they *DO NOT* require additional power to keep them running. There is NO power cord for the magnet and the current will run FOREVER so long as the coil is kept cool enough to remain superconducting (usually using liquid helium as mentioned previously).
An enormous amount of energy is released when a magnet "Quenches" i.e. heats up and becomes non-superconducting. Once the coil has non-zero resistance a ton of heat is generated, the liquid helium boils off, and the coil can expand causing permanent damage to the magnet. Furthermore, when the helium gas boils off it can displace all the oxygen in the room creating another hazard: asphyxiation.
While most systems have a "Quench" button which has been engineered to be as friendly as possible to the magnet, it is a costly and risky maneuver which is reserved for cases when human life is in danger i.e. someone walks in with a non-MRI safe gurney which pins someone to the magnet... It has happened.
The point is, this is not a magnetic field that can switched off easily/cheaply and turned back on quickly/cheaply!!
As for metal implants, it is important to remember not all metals are magnetic, and most implants are made of MRI Safe materials i.e. won't rip out of your skin in the presence of a strong magnetic field. However, most are not "MRI Compatible" meaning they will cause image artifacts in a small area around their location.
MRI is safe, working with humans around an MRI is the dangerous part.
You have be in basically a sealed off room to die from helium. I have been working for cryogens for 9 years, and while I have always heard *you can die from the gas* it is a little ridiculous with helium. It is lighter than air so it will float to the top of the room and escape to the atmosphere.
Maybe us physics people are crazy, or it is the physical size of our magnets, or we just know how to fix them when they go bad... but I always just ramp the temperature when I want to kill the field. And you can ramp the current to change the field. This I have done.
we look like chumps!
What he said... except the part about asphyxiation.
You have be in basically a sealed off room to die from helium. I have been working for cryogens for 9 years, and while I have always heard you can die from the gas it is a little ridiculous with helium. It is lighter than air so it will float to the top of the room and escape to the atmosphere.
Maybe us physics people are crazy, or it is the physical size of our magnets, or we just know how to fix them when they go bad... but I always just ramp the temperature when I want to kill the field. And you can ramp the current to change the field. This I have done.
Thing is, its not just helium thats doing the cooling.
A lot of MRI's also use Nitrogen to mediate the temperature between the helium / wire, and helium / atmosphere barrier to prevent cracks in the containment chamber, and unwanted condensation near the electronics.
If a quench occurs, it will release both gasses into the room in the event of a ventilation failure. If you enter the MRI room without leaving the door open, the pressure differential created by the quench can create enough force on the door to prevent you from opening it, causing you to be stuck in a room with a quickly diminishing supply of O2.
Thus...you die.
Always leave the door open when you are using the room.
*short