Until you experience...
frank freedman
Posts: 1,983
It's one thing to say OMG or chuckle at some of the collections on you tube, quite another to experience it.
Had a call tonight, a sharps container ended up in the bore of a 3T MRI. Took five of us and a 1/2 ton chainfall pulling on 2 20' x 3" wide tie down straps to free it. This container frame base was maybe 1 /16 or an 1/8 inces thick and maybe 9" square. Couple pounds maybe? 
Comments
I hope no human was inside the scanner🙈
Wowzers!
Can you post a bit of the back story? Was this holder bumped off a wall and flew, or maybe pulled off a passing cart, etc? How did it even get into the room?
frank freedman,
Some lawyer must be salivating at the money to be made from this monumental screw up.
Not sure how it got close enough to get pulled in being called after the event. No patient present at the time, no staff hurt. Sorry lawyers, no soup for you this time.
As to humans, we chose to pull the plastic container out and reduce some of the magnetic parts of its cage. There is a pretty wide bar that goes across the top. The guy working on this with me went inside from the rear of the (fairly large) bore to take this part out. I wished I could have put that on tic-trash. As he wriggled out of the bore the part would pull to one side then when he got it away from that side it would whip to the outher side. So he's trying to work way out as this metal is yanking him side to side. Imagine a high tech three stooges gag...
As to flight, it took two attempts to remove it. Ran out of chain (7734 yes, the chain hoist did NOT enter the room). It had gotten far enough to almost be free, and it was whipping around just inside the bore before being yanked back to one point inside the bore. Second time adjustments allowed the extrication to be successful.
It was an adventure. After, bit of bondo and Mr Clean eraser pad and good to go. Up and restored to normal use after functional and image quality testing to assure no magnet damage.
If physical removal is impossible, what do you do? Initiate a quench?
Actually you can ramp down, but it takes a day or so. Then remove object, repair physical damage and another day ramping up. Not cheap in terms of down time, but a quench will run around 80k plus or minus because you will dump lots of helium. Have heard about a week to come back from that. Quench would be for extreme situations. This was at the end closest to doing ramp down. 1/2 ton chainfall barely got it out. If not then rampdown would have been the way. When you pull a thing out, those magnets mounts/coils have the same force on them trying to keep hold of what you are trying pull out. Wheel chair, bed, 02 tank. You are not likely to remove with a live magnetic field.
“Ramp down” = off to youtube to learn something new! 👍