Bullets are generally non-magnetic.
I’ve only had one, but not having swallowed any ball bearings, I wasn’t worried. I did have to get my eyes checked for metal particles though. Luckily none found.
52100 is probably the most commonly used ball bearing because of its low cost. It has low nickel content, which seems to be the most critical factor. But it is not recommended for corrosive environments like the stomach. I would suggest only swallowing ball bearings which have high corrosion resistance.:rolleyes:
In fact I was correct in saying ball bearings usually are made of stainless steel. Almost all of the steel bearings contain chromium and would qualify as stainless. But I was incorrect in assuming it was the chromium that provided the non-magnetic quality, as noted in my followup. So it’s all going to depend on the type of ball bearing swallowed. I would recommend everyone swallowing ball bearings stick to a material with a high nickel content, or better yet, ceramic bearings.
As far as the ability to harm people, I’m still suspect of the idea that MRIs can apply enough force to a large ball bearing in the stomach to cause severe injuries, though I wouldn’t want to test the theory on myself.
A couple of barely related side notes; Super magnets can be dangerous if more than one is swallowed. Tissue can be pinched between them causing severe injury, and cows are routinely fed (force fed i think) large magnets to collect metal they might consume in the stomach (or one of those things in a cow sometimes called a stomach). So before giving your cow an MRI, check to see if its been fed a ‘cow magnet’.
Do you ever watch House??? They had a character that swallow a Key for one of his magic acts and when they gave him an MRI it was ripping through his intestines. . .
It doesn’t really matter what any of us say if you want to try it your goin to do it either way just be cautious. . . You don’t want to end up on 1000 Ways To Die because you swallowed a ball bearing before having an MRI. . . Just sayin!!
I’m aware of the aneurysm clip issue; it’s well known and is caused by the clip vibrating loose. The clip only has to move a millimeter or two for it to fail, leading to a hemorrhagic stroke. The ball bearing case is not comparable; a ball bearing vibrating a millimeter or so in your gut isn’t going to cause serious injury.
I wouldn’t cite House as authoritative on anything except on how to behave like an ass.
Cecil has a bit on the magnitude of internally appled force needed to generate injury:
Is it dangerous to use an air hose to induce flatus?
Now air pressure is a pervasive force, rather than a point source, but it’s clear that an external supermagnet could put several pounds of pull on an internal ball bearing.
Bullets are almost always made out of lead.
Keys are almost always made out of brass.
“House” is probably not a good information source on this issue.
This Wiki link says:
This link on 52100 steel gives the following percentages:
IOW, large ball bearings typically have about one-seventh as much chromium as does stainless steel.
You seem to dispute the New York Times article I cited showing that metallic objects don’t just vibrate - they translate with deadly speed and force -when exposed to the magnetic field of an MRI.
Will a video demostration be more convincing?
Do you now see that vibration of metallic objects is not the only concern?
:smack: mea culpa, mea culpa. I knew that once upon a time and complained about something being called stainless steel when the chromium content was too low.
So I would have been correct if I’d said some ball bearings are made of non-magnetic stainless steel. But I didn’t, so I was wrong, wrong, wrong.:smack::smack::smack:
Hamster, only swallow non-magnetic stainless steel or ceramic bearings before you get an MRI;)
I’ve got a related question: do MRIs have any effect on amalgam dental fillings?
Like on the Red October? Cool!
*House *is probably not a good information source on any issue. That was kinda my point!
I don’t think anybody is arguing that being struck in the head with a heavy metal object or having a life saving surgical appliance pulled loose was not dangerous, but that’s not really what the OP is about is it?
It seems to me that a person with a large metal object in them might feel the pull and notice some ‘discomfort’ before he/she got that close to the machine.
The fillings are non-ferrous, so there is no danger, however like any metal, the RF induction will create artifacts (distortions) in the image if it is taken around the face/head.
An MRI scanner won’t yank fillings out of your teeth, but the metallic components of the amalgam can make for some interesting starburst like artifacts in the images.
Now I’m curious - I’ve got images of my head showing starbursts in my teeth, but they were from before I got the gold crown. I wonder what that would look like?
**Paging Mythbusters… **
If they can find someone who’s about to decommission a scanner and doesn’t care if it or the MRI suite is damaged, I’m thinking that they could put some ball bearings in their favorite “human analog” aka ballistics gel, and bring them into the magnet room. On the assumption that bearings are weakly magnetic or not at all, they’ll also have some ballistic gels made up with some standard steel nuts or bolts. Those will probably be dramatically yanked out of the gel and into the scanner bore, where it may require a quench and shutdown to pry them loose. (Hence the suggestion of finding some old unit that’s headed for the scrap heap.)
All Mythbusters would really need is an instrument to measure the force on a metal object. Not that they’d stop there, of course. My guess would be a butchered pig.
An MRI is not an instrument one can arbitrarily turn “down” for a Mythbusters experiment. There is a huge static field, and a massive amount of shunning the field in order to get it right. No hospital will touch those shims just for a TV show.
Any non- ferromagnetic metal (or conductor for that matter)is in danger of heating up. A ferromagnetic metal will go ballistic, but I suspect that that static field never gets turned off, so you wont get anywhere near the field before trouble. Also, it might quench the magnet, although I’ve never heard of it happening.
They’d probably try to make a machine of their own if they could do anything. How expensive would it be to create something that has similar magnetic fields and oscillation.
Not at all convincing as it relates to the question set forth by the OP. Obviously an oxygen canister that has been accelerating across a four foot length is going to hurt when it finally hits something, but that certainly doesn’t mean that oxygen canister would rip through a human body if it started out adjacent to it.
Similarly, I can easily and comfortably hold a very large steel ball-bearing in my hand, but I wouldn’t like that same object dropped from four feet above my head.
The simple fact is that people go into MRI’s with large amounts of metal in their bodies all the time whether they’re supposed to or not, and serious injuries are very rare and usually related instead to dense metal objects that accelerate for a while and then hit the patient.
Uh, because MRI machines really aren’t that cheap, I’m going to guess the answer to this is, “a lot of money.”