Phone dropped down chimney :-(

[Andrew Mawson]

Wiped mine out very effectively when I went for a body scan a few years back!

AWEM

[Derek Geldard]

It depends how big (and strong).

Years ago at work we had a large screen CRT TV expensively built into a shipping case with wheels and a power operated elevating platform for playing demo tapes on exhibition stands.

It turned out to be unuseable because the exhibitions were medical imaging exhibitions and there were always several, 2-3 Tesla MRI machines in the show.

As somebody has pointed out, aren't they used in the disk drives ?

DG

[Derek Geldard]

Credit cards may be more permanent , but the magnet in an ordinary mobile phone speaker/earpiece can easily spoil the rewriteable track on a cardboard carpark ticket. Usually necessitating a long trek on foot to the carpark security office. :-(

DG

[Andy Hall]

Hotel room keys as well.

Place key in same pocket as phone all day and an extra trek to reception in the evening.

Place key card in wallet and a small collection grows. Perfect for defeating those annoying switches that require a room card before the lights can be turned on.

[Aidan Karley]

[snip]

That's a SERIOUSLY strong magnet. But it's also an alternating field, which is *much* worse for data storage devices than being introduced to a static field.

[Andrew Gabriel]

I didn't get to carry anything like that into the room. Track suite or pyjamas only, and with no metalic parts. There are fatalities from MRI scans. They are caused by wheelchairs, oxygen cylinders, etc which had seen brought into the room and left by the door flying towards the patient when the magnet is switched on.

The maximum permitted field strength for medical work is 2T, which is probably less that one could find in a loud speaker or disk drive magnet gap. What is remarkable about the MRI scanner is achieving a 2T field inside a large enough volume that a person's body can be exposed to it.

When the team which invented MRI were first ready to try it on a living human, they used one of their little fingers. They had to go around the team finding who had the smallest little finger, as that was all they could fit into the scanner they had built at that time. (This was covered in a program on the invention of the MRI scanner on Radio 4 some weeks ago.)

-- Andrew Gabriel

[the_constructor]

Just going off topic for a moment if you don't mind. I saw a film a few months ago inwhich a person who had a small fragment of steel in his eye was placed in a MRI scanner and when the machine was turned on, the metal was pulled into the chaps brain by the magnetic field. Anyone know what film it was please.

[Bob Eager]

Just glad they didn't give me an MRI while I had a little metal canister sewn to the back of my eyeball...!

[Chris Hodges]

We get these magnets delivered to work almost weekly. I'm afraid the answer's boring - a small box, chips and a larger box to give a decent (~1-2") air gap

[deckertim]

glad they didn't give me an MRI while I had a little metal canister

I had a scan a few years ago as I had a prolapsed disc in my back. There was an extensive questionnaire about whether I have ever done any arc welding, or had any accident where I might have had metal fragements in my head, so this is clearly a potential problem. The post about people with piercings being ripped from the body has to be an urban myth.