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| Result: Searchterm 'Safety'
found in 15 messages |
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More Results:  Database (107) News Service (69) Resources (43) |
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Barry Ng
Wed. 10 Jul.13,
17:10
[Start of:
'Titanium & MRI Safety'
2 Replies]
 Category:
Safety
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| Titanium & MRI Safety |
I am trying to understand why titanium is considered "MRI Safe".
I see three potential problems when considering the MRI safety of a material:
1 - If it is a ferromagnetic material extreme damaging forces will be applied to the material if exposed to a very strong magnetic field. Titanium is not a magnetic material so I do not see this as a problem.
2 - When a relatively large flat conductor (e.g. a titanium plate) is exposed to a changing magnetic field (Faraday's law) eddy currents will be created internally as the result of induced voltages. These eddy currents can be very high and cause resistive heating ("I squared R losses"). I would think these eddy currents would have the potential to cause extreme heating of the titanium. I know from experience this does occur with steel and titanium has a conductivity about the same as steel. Titanium is not magnetic as is steel but induced voltages due not require a ferromagnetic material (.e.g. copper as used in real world generators, etc.).
3 - Induced voltages are created across the length of a conductor as the result of the conductor being exposed to a changing magnetic field ("genrator effect" - Faraday's Law). Again this effect does not require a magnetic material. So why, at best, does this effect not have the potential to be uncomfortable or even very painful to the MRI patient being exposed to a huge changing magnetic field?
Invariably the response to why titanium is safe focuses on the fact that it is not magnetic. I get the deer in the headlight look when I ask about eddy current heating and induced voltages.
Please help me understand why unduced eddy current heating and induce voltages are not a concern.
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Antonio Dominin
Mon. 14 Aug.17,
00:03
[Start of:
'MRI Safety w VNS Lead Still In Body'
0 Reply]
Category:
Safety
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| MRI Safety w VNS Lead Still In Body |
Hello Everyone!rn:-)rnrnPlease forgive me in advance for making any newbie mistakes here. I am new and appreciate your kind correction of any errors that I might make.rnrnI am a patient with many, many illnesses. In 2006, I was in the deepest depths of depression and could not see any other way to treat it, other than the newly approved (then) Vagus Nerve Stimulator (VNS) for depression.rnrnNeedless to say, it did not help at all and, after over 2 years of VNS therapy, my doctor and I agreed to turn it off. (It makes the neck muscles move when it is stimulating the vagus nerve, which can get annoying after a while.)rnrnWhen I got the VNS implanted, I was told that I would never be able to have an MRI done, except with special equipment, called a transmit & receive coil. This wasn't a problem because my hospital, Olympia Medical Center, here in Los Angeles, had one of these.rnrnHowever when they upgraded their equipment in the years following my implant, they no longer had a transmit & receive coil for the new machine, and I could not find any place in LA that did have this coil.rnrnNow, since I have so many illnesses in my life, the possibility that I will need an MRI in the future is great. Therefore, I called and spoke with the assistant of the Neurosurgeon at USC Keck Medical Center that implants VNS, and he could therefore remove the VNS.rnrnHowever, the assistant said that, while he could remove the VNS device itself, he would probably have to leave the lead to the vagus nerve in the body because of it's attachment to the nerve has probably grown in at this point.rnrnMy question is this: Will I be able to safely have MRIs in the future with this lead still in my body? At this point, I am thinking that I might have to have MRIs of my brain (Parkinson’s disease, exotropia), wrist (Carpal Tunnel Syndrome), C-spine (prior to doing occipital nerve blocks). Do you have any other comments or suggestions on my situation?rnrnThank you very much for your kindest consideration of my post. I look forward to hearing back from you, and I will await your replies. rnrnBest regards,rnrn~Antonio Dominionrn:-)
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Derek Andrade
Thu. 7 Nov.13,
21:41
[Start of:
'"Gadolinium Enhanced MRI" safety question?'
0 Reply]
Category:
Contrast Agents
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| "Gadolinium Enhanced MRI" safety question? |
Is having 2 separate "Gadolinium Enhanced MRI's" within 3 days safe? I have a Gd-MRI for my SI joint scheduled. 3 days later I have another Gd-MRI for my brain. I don't have kidney problems.
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Reader Mail
Wed. 24 Aug.11,
19:00
[Start of:
'Stent Safety and repeated MRI exposure'
1 Reply]
Category:
Safety
|
| Stent Safety and repeated MRI exposure |
We have a anesthesia tech that has a stent in her aorta. The stent is safe at 1.5t. She at times needs to stay in the MRI room with a patient during the scan. She may do this several times a month. Is there any long term effect? Can the stent become magnetized over time? Cannot find any documented information.
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Kryptonite global
Wed. 27 Apr.22,
05:34
[Reply (2 of 3) to:
'Titanium & MRI Safety'
started by: 'Barry Ng'
on Wed. 10 Jul.13]
Category:
Safety
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