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Community => The Lounge => Topic started by: Askold on October 07, 2014, 01:36:54 am

Title: Remove all metal items before going to MR scan
Post by: Askold on October 07, 2014, 01:36:54 am
Demonstrational video explains the dangers of bringin metal items to MR Imaging enviroment:

http://www.youtube.com/watch?v=6BBx8BwLhqg


An article from American Journal of Roentgenology concerning an actual case of someone with a metal item in MR: http://www.ajronline.org/doi/full/10.2214/ajr.178.5.1781092

In this particular case that metal item happened to be a .45ACP pistol. 'MURRICA STRONG!!! RIGHT TO BEAR ARMS!!! RAARHG!!!

(http://i.kinja-img.com/gawker-media/image/upload/s--0fPxl4jt--/18m7tuyanxopfjpg.jpg)

Because you should never surrender your second amendment rights when it puts other people in danger.

(click to show/hide)
Title: Re: Remove all metal items before going to MR scan
Post by: Sleepy on October 07, 2014, 07:06:49 am
Wow, that's ridiculous. I have an MRI roughly every year, and restrictions have gotten even tighter recently. I used to be allowed to wear my normal clothes for the procedure, but now they force me to change into a hospital gown. They also freaked out at me one time because they thought I might be pregnant (all I said was that I hadn't had a period lately, because birth control does that). They're careful as hell.
Title: Re: Remove all metal items before going to MR scan
Post by: Old Viking on October 07, 2014, 03:20:00 pm
Do they realize those machines probably cost close to $100?
Title: Re: Remove all metal items before going to MR scan
Post by: Ultimate Paragon on October 07, 2014, 03:31:19 pm
Quote from: Sleepy on October 07, 2014, 07:06:49 am
Wow, that's ridiculous. I have an MRI roughly every year, and restrictions have gotten even tighter recently. I used to be allowed to wear my normal clothes for the procedure, but now they force me to change into a hospital gown. They also freaked out at me one time because they thought I might be pregnant (all I said was that I hadn't had a period lately, because birth control does that). They're careful as hell.

Well, I guess they don't want to take any unnecessary chances.
Title: Re: Remove all metal items before going to MR scan
Post by: Svata on October 07, 2014, 03:42:18 pm
Quote from: Old Viking on October 07, 2014, 03:20:00 pm
Do they realize those machines probably cost close to $100?

You, uh, might be missing a zero or two in there.
Title: Re: Remove all metal items before going to MR scan
Post by: Cerim Treascair on October 07, 2014, 06:43:22 pm
Uh... YEAH! I thought this was common fucking knowledge! MRI's use incredible magnetic fields! DUH!
Title: Re: Remove all metal items before going to MR scan
Post by: Søren on October 07, 2014, 06:48:33 pm
People with dodgy tattoos can't even get mris. When I got an MRI I was asked where I got mine
Title: Re: Remove all metal items before going to MR scan
Post by: chitoryu12 on October 07, 2014, 09:52:57 pm
Quote from: Svata on October 07, 2014, 03:42:18 pm
Quote from: Old Viking on October 07, 2014, 03:20:00 pm
Do they realize those machines probably cost close to $100?

You, uh, might be missing a zero or two in there.

He said close. Not how close.
Title: Re: Remove all metal items before going to MR scan
Post by: Hoplite on October 22, 2014, 10:19:10 pm
Yup. I got kicked out of a MRI room because I had a bismuth bandage patch over a 2nd degree burn. Bismuth is a metallic element.

It took a good two weeks to get another appointment.
Title: Re: Remove all metal items before going to MR scan
Post by: Sigmaleph on October 22, 2014, 11:03:11 pm
Interesting. When people think "metal near magnets", they're usually thinking of ferromagnetic stuff (iron and iron alloys like steel being the most common example), which has a very strong response to magnetic fields. Bismuth is diamagnetic, which means that it's repelled by magnets rather than attracted to them, and that this response is, relatively speaking, very weak (for reference, water is diamagnetic. Not as much as bismuth, but still).

My point being that, metallic or not, bismuth is not going to react to the MRI like something made of steel would. Maybe its high diamagnetism means you get bad results or something.
Title: Re: Remove all metal items before going to MR scan
Post by: Svata on October 22, 2014, 11:24:49 pm
Or, being repelled from the sides, would either lift and/or tear through (if on side nearest magnet) whatever limb/part of your torso it was attached to.
Title: Re: Remove all metal items before going to MR scan
Post by: chitoryu12 on October 23, 2014, 12:36:58 am
Quote from: Svata on October 22, 2014, 11:24:49 pm
Or, being repelled from the sides, would either lift and/or tear through (if on side nearest magnet) whatever limb/part of your torso it was attached to.

Depends on the relative strength of everything. It's perfectly possible that any repelling strong enough to move the limb the bandage is attached to would simply tear the bandage off. And it could only go through the body if it was already dense or sharp enough to do so simply by being pushed hard enough (and cloth bandages with minor amounts of metal aren't exactly heavy weights).
Title: Re: Remove all metal items before going to MR scan
Post by: Svata on October 23, 2014, 12:58:58 am
Fair enough. It was just a guess based on what ferromagnetic things would di if pushed into the opposite direction.
Title: Re: Remove all metal items before going to MR scan
Post by: Sigmaleph on October 23, 2014, 01:45:58 pm
Quote from: Svata on October 22, 2014, 11:24:49 pm
Or, being repelled from the sides, would either lift and/or tear through (if on side nearest magnet) whatever limb/part of your torso it was attached to.

The key thing is that diamagnetic effects are much weaker than ferro- ones, and even a strongly diamagnetic material like bismuth should only result in very weak forces. But it's not like I've done the math on it, so don't take my word for it.