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1.  

   No Subject Given

   

   Joe Schmoe, Aug 19th, 2005 @ 2:23pm

   
   

   Well call me a moron then. I never know that the magnet is "never off".
   Wouldn't have guessed. Woulda figured it was off when not in use...

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2.  

   CERN and magnets

   

   Chris Maresca, Aug 19th, 2005 @ 2:26pm

   
   

   I once spent a week at CERN (www.cern.ch) where they have HUGE magnets that control plasma in an attempt to create fusion. When they first started using it, they had a huge problem with left-behind tools flying through the air when they turned them on (no threat to anyone as they flood the area with nitrogen before firing it up), but you can imagine what might happen when the thing is fully operational with plasma inside.

   The solution was to build a bunch of titanium (non-magnetic) tools, which was very, very hard and expensive to machine at the time. So CERN engineered a new way of machining titanum, which has since lead to machined titanium things being relatively cheaply available to consumers (watches, rings, etc.).

   Chris.

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3.  

   Re: No Subject Given

   

   Anon, Aug 19th, 2005 @ 2:41pm

   
   

   I think he was referring to staff only. I would hope that you don't run an MRI machine and not know how it works.

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4.  

   No Subject Given

   

   TJ, Aug 19th, 2005 @ 5:23pm

   
   

   The linked article has a correction at the end of page two about the helium. It is used to cool the magnets, not power them. Good to see since I didn't understand how liquid helium would help power a magnetic field.
   
   Boy the idea that a small sliver of metal in their body blinded a patient gives me pause about having an MRI. A metal shaving penetrated one of my eyes when I was younger, and doctors said it was best not to try to remove it. Hadn't thought before now that it might blind me later during a medical test. Yeesh.
   
   Hopefully T ray technology will advance sooner than later and help replace these useful yet occasionally dangerous MRI systems.
   

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5.  

   Corrections

   

   dorpus, Aug 19th, 2005 @ 7:12pm

   
   

   "MRI magnets are never off, even when the power is cut, because they draw power from supercooled helium, "
   
   Correction: the article says the magnets, which are superconductors, will stop being so strong once the helium is drained. It does take a few minutes to release the helium, and a sudden release can cause problems also, e.g. the clinic whose roof blew off when supercold helium blasted into the atmosphere.
   
   
   "though one company is working on a new generation of scanners that only attract ferromagnetic metals like iron, nickel and cobalt."
   
   When you say "scanner", I assume you mean the walk-through scanners at the entrance to the clinic which detect ferromagnetic metals. You can't make MRI magnets that "only attract ferromagnetic metals".
   
   
   

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6.  

   Re: No Subject Given

   

   Danielle, Aug 20th, 2005 @ 4:32am

   
   

   very common thinking. Even some doctors in our hospital try to walk in with stethoscopes and other metal, thinking the magnet is only on when we're scanning. I've heard of many cleaners that come in after hours to polish the floor and assume the magnet is off. Luckily we've never had any incidents in our scan room (YET!!).

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7.  

   No Subject Given

   

   Chris, Aug 20th, 2005 @ 9:04am

   
   

   My sister is a radiologist and she said the wire in her bra gets pulled toward the machine when she walks in the MRI room.
   
   I doubted one of the stories about how strong the magnet is, boy was I surprised when she told me.

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8.  

   Sign in the Medical Imaging and Diagnostics Room

   

   Anonymous Coward, Aug 24th, 2005 @ 8:32pm

   
   

   Please remove *ALL* body piercings and modification accessorties... go ahead, don't be shy about it. You don't want to suffer the consequences of non-compliance due to embarassment.

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9.  

   cost of machines

   

   thanesha hamilton, Mar 23rd, 2006 @ 1:49pm

   
   

   need cost of mri machine for a new business and what the the guide lines for credit and cash pay.

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