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This doesn't track to me. People have been irrationally afraid of things since the dawn of time, based purely on hearsay (see religion). And surely even the simplest of language serves to warn about unseen dangers.

Entering the MRI room myself I was very familiar with the dangers of bringing metal inside, to the point where I would second guess myself and my own body. "What if my leg bone actually has metal in it for some reason?!"



There are people who flock towards information about technology (probably almost everyone here as well as many in their social circles) and there are people who run from information about technology.

I know people who if you tried to explain an MRI to them, would become visibly uncomfortable and search for any way to change the topic.


>I know people who if you tried to explain an $X to them, would become visibly uncomfortable and search for any way to change the topic.

Expected behavior. Explanations of complex topics are to be rejected if explainer does not have sufficient authority to make behaver hold-still-and-listen.

I know such folk, too, and this is among the thing about people which annoys me to no end. If a MRI tech tried to explain the shit to one such acquaintance, they would try to change the subject like you say. OTOH, if the doctor in charge tries the same, the listener will instead have to zone out. But zoning out is a more expensive operation, as any zooner knows. (Which is why they hold doctors, lawyers, and other semi-priests in high reverence, up to pushing kids to take up these rather joyless professions to the exclusion of all sense.)

Peeps here equally well-behaved other way round tho. C-f "mal" = 0. Geez I really needed to witness the absolute by-the-book Freudian slip that can be found at 1:55 of one of the probably infinite interview cuts, then have MRI safety explained to me by hacker noosers on their Monday morning.


Is law really joyless? IANAL but it seems like competitive puzzle solving, essentially.


And medicine might, to some, seem like the use of science to save lives, but hey -- a shooting war is also a kind of competitive puzzle solving, and I assume there are people who find joy in that, too.


I think people are just not aware of how bad it is. People might think it's "fork in microwave" oopsie bad, not "fire at the gas station" fatal bad.


It’s certainly bad enough that you shouldn’t be able to enter a room with an operational MRI machine just like that, as a normal guest with no training and no escort. One cheap RFID reader could have saved a life here.


> "What if my leg bone actually has metal in it for some reason?!"

I have a titanium plate in my head, so it's not magnetic.

When the MRI tech asked if I had any metal in me, I said I had titanium on my skull.

She asked if I was sure it was titanium.

I knew it was, but I was nervous, so I said, "I think so."

She half-joked, "Well, if it's not, we'll find out real quick."

It was titanium.

But they never really double-checked or anything.

Part of me thinks that because of my age, she could tell it wasn't iron or anything dangerous.

But another part of me feels like she honestly didn't care that much and meant it when she said we'd find out fast.


It’s probably of the “if it’s in your head, it can’t be anything other than titanium” variety. It’s not like they’re going to break open your head to check.


From what I gather, it's between the 80's and 90's that titanium became the norm.

Wouldn’t your head have started to get pulled towards it as you approached, so maybe you could stop approaching once you felt something weird going on in your head?


Powerful electromagnets don't work like that. They may switch on and off, and if you are in range, the motion is almost instantaneous.

Its not like in the movies where you have to be right up on it, and certain materials may attract at higher rates depending on the amount of ferromagnetic materials affected by the flux.

Field flux lines may also be warped depending on the geometry so its possible the drop-off wasn't calculated properly during initial facility design, or it changed.

Walking through the wrong door can have consequences as the news has reported.


You normally hear it describes as the "field falls off according to inverse cube" but the consider what that means about how the field increases.

The effect for magnetic fields is that generally once the field is enough to obviously move an object it's already accelerating uncontrollably.


Both can be true. We learn to fear and respect modern technology because of training and reinforcement that might occur as part of learning.

Consider the “Things I Won’t Work With” column. There is a healthy degree of respect for various compounds that’s learned with experience. This is similar to the way that (properly trained) electricians work with electricity, and nuclear plant techs work around radioactive material.


> "What if my leg bone actually has metal in it for some reason?!"

I had that constant thought for the 15 minutes of my knee MRI (except s/leg bone/body/). Most discombobulating.


There's lots of ways we could have metal in our body. A hip replacement, a forgotten piercing, old tooth fillings, maybe you accidentally swallowed some piece of metal.

If MRI scanners are this deadly, everybody should be really thoroughly screened and scanned to be allowed into the room. And even into the room next to it. How can the door of that room open while the machine is still turned on? (Edit: apparently the magnets in these machines usually can't be turned off, which changes the question to: how was he allowed to enter the room at all?)

But wearing such a heavy chain while accompanying your spouse to an MRI scan, is also not the best move.


> There's lots of ways we could have metal in our body. A hip replacement, a forgotten piercing, old tooth fillings, maybe you accidentally swallowed some piece of metal

One of the reasons they ask what you do for work is because if you're doing some sort of job that involves working with metal (e.x. cutting pipes, welding, etc) there are extra precautions to take.


Indeed. The hospital will pay a lot of money. Metal detectors are insanely cheap, there's no reason why there shouldn't be one before reaching the door as a default cautionary measure.


Depending on how or where they are installed, they risk being pointless. Every human has mental on them and it’s mostly safe (in shoes, bra, zips, buckles, access swipe card). Little bits of jewellery are fine. Surgically implanted metal is mostly fine.

Having an alarm that goes off for a staff member’s bra 200x a day leads to normalisation of hearing the alarm, and the unsafe things gets missed.

Im an MR tech.


Of course you don't want to ignore that alarm 200 times a day. That's why I'd rather just ban everything with metal. All of these things have non-metal alternatives that you could easily enforce in such a specialized setting. Why wouldn't you, if it can save lives?


That's a very easy fix. Just make the volume proportional to the amount of metal detected.


And the 10+ a day with a knee joint or a hip joint replacement?

And then what if they also have a pacemaker or aneurysm clip?

An unsafe clip is tiny, and it will kill them. You can’t depend on a metal detector.

Technology might help, but people following process is what safety depends on.

If staff follow the rules the MR suite is very safe.

https://mrisafety.com/


What does this mean? I thought you can't get close with any ferrous metal whatsoever. If it beeps, you're not allowed in. It's not like in an airport where "oh it's just a coin".


No, you can.

Belts, buckles, bra etc are fine on staff.

A coin is a problem. Hip or knee joint replacement and various screws and plates are fine (some contain some iron).

Like all bad answers, the answer as to whether it’s ok in the scan room is ‘it depends’.


Metal detectors can detect nonferrous metals too.

The walls are usually made from mu-metal. This is a metal mixture that blocks/attenuates magnetic energy.

Spinning rust hard drives are also made with mu-metal as well.


I had two head MRI’s, and both times I was equally terrified my metal fillings would start bouncing around my head.


Wait till you learn about Peripheral Nerve Stimulation effects:

https://www.robarts.ca/scholl_group/research/peripheral_nerv...


Hehe, in my case I used to have a metal filling that was removed, but I was still worried about a missing piece of it or something.

Apparently it's not an issue, even if you do have them.


My first MRI I confirmed I have no metal on my body to the technician, but by the time I was inside I suddenly remembered I have metal fillings. I was so stressed by the time the machine turned on, but yeah no problems at all


The machine was already on by the time you were in it. The magnet does not get turned off.


True, but the RF coils do get turned on & off. Heating of non-magnetic metal from the radio waves used for scanning is another concern, not just magnetic force.




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