How dangerous are magnetic items near an MRI magnet?

UPDATE: Questions about why we were doing what we were doing? Please see the FAQ under "MRI magnet quench: the movie." That video is also entertaining, btw.

Fun, games and safety implications with a 4 tesla (T) MRI magnet that was about to be decommissioned. Note how magnetic objects let loose tend to oscillate along the magnet bore. That's because the peak magnetic field gradients are at either end (near the magnet face), causing peak acceleration as the object enters, followed by progressively damped changes of direction. See practiCalfMRI.blogspot.com for more information.

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  Science & Technology

[redwinmedia]

This is not a modern scanner, let alone a clinical scanner. This is an OLD 4T research magnet with an enormous fringe field. In the interest of full disclosure on behalf of practiCalfMRI, no one getting a routine MR scan would be exposed to this field strength.

[practiCalfMRI]

The 4 T magnet was actively shielded so the fringe field was fairly well constrained. Modern 3 T magnets are also actively shielded, but there is of course a difference in overall stray field strength because 4 > 3! Thus, the overall fringe field was definitely larger for the 4 T than a new 3 T clinical scanner, but the effects wouldn't be drastically different on a new 3 T. As a general rule, the "point of no return" can be considered to be halfway down the patient bed for both.

[stickdiggler]

this is why i always take off my cock ring before getting an MRI

[Anne Hsu]

Typically it's the "cheaper" metals that are issues in conjunction with size. Large objects are bad news. I've heard stories of medical staff wheeling in wheelchairs and they get sucked right into the magnet at high speed. But prosthetics and most metal due to surgery in the body are not a problem as they are lodged into place pretty well. People with pacemakers cannot go in though bc of the tiny wires and of course people who might have metal in their eyes or those who've been shot before.

[n8rm8r2]

kinda glad my face didnt explode! O_O

[n8rm8r2]

i am happy to share :) :)

[dayoneofit]

this is what i want to know XD thanks XD

[TheMackLyons]

And no one thought to stand clear of the metal cable that could have whipped back and slashed someone's face open had it suddenly snapped under tension?

[Farie Indriawan]

Throw a nokia in !

[solartechjames]

Is this why we can't get medical treatment in this country for free? Because somebody's off fucking around with the MRI? God bless the US. Jesus, SMH.....

[solartechjames]

Silver isn't all that magnetic. My mom had some staples from a surgery years ago, went to go get an MRI and had those all bundled up in her. She wasn't even aware she had the staples

[n8rm8r2]

i got 4 silver molar fillings, a few yrs ago i got scanned, didnt feel a thing... they didnt even ask me about fillings >:/

[n8rm8r2]

SERIOUSLY!!! im totally gonna start looking for used MRI's now.