Demonstrating the power of MRI magnets
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- เผยแพร่เมื่อ 26 ก.ย. 2024
- The Neuro's McConnell Brain Imaging Centre is home to Canada's first 7-Tesla whole-body magnetic resonance imaging machine. The powerful magnet can deliver precise images of the human brain.
Here researcher Rick Hoge demonstrates how magnetism in the MRI room causes unusual behavior in metals and why safety is very important to prevent injury.
For more info: www.mcgill.ca/...
#magnetism #lenzlaw #appliedscience
I mean, I understand the message you're trying to convey - but as a youtube community member, I believe that I speak for everybody when I say that we're going to need to see scissors vs ballistic gel block accelerated by the MRI magnet to be convinced of your warning.
lol, I was thinking something similar. I would have liked to have seen a pair of scissors perhaps attached by a metal cord brought near the MRI
Given the forces involved, it would not be realistic to bring them into the machine itself
I was thinking the exact same thing. Hopefully they’ll do it.
Absolutely lol
That's a very expensive piece of equipment. They're not going to damage it for views. However you can find images of objects that people were dumb enough to bring near the machine
@@LoneHowler I don't know where you're from, but you clearly don't belong here.
Honestly, I think punching the aluminium plate as it slowly descends is probably the best demonstration you could have done. Just letting it slide gently makes it seem like there's only a small force holding it back. No. You'd have to push really hard to make it go any faster.
Because of Lenz's law - the principle behind the behavior observed, pushing it doesn't really accelerate the descent much, since the stronger the force causing the plate's movement, the stronger the resisting magnetic field will be. Still, interacting with it like that does make it easier to see just how strong these magnetic fields are
you did watch the end of the video where he punches the plate right? you make it sound like he didnt.
Um, no. He makes it sound like he did
He literally says "punching the plate is the best demonstration you could have done". @@Lange007
@@Lange007 He did - that's my point. It was a very good demonstration of the forces involved. It looked like they threw it in as a joke, but it's probably the best bit of the video.
@@TheKejufish Yup. Knowing the law is one thing. The guy did a good job explaining it. The physical interaction makes it much easier to understand intuitively, though.
It reminds me of the Mythbusters toying around with catching bullets in your teeth. Sure, I knew it was impossible ahead of time. Seeing the bullets shred themselves into paste really brought it home.
Dogs can't use MRIs. But Catscan.
That's actually pretty good - well done!
Whoop whoop! 💃🍭🥇🎺
😂
🐱🐈
That's Funny 😁
I used to audit the installations of MRI scanners. One patient was a car mechanic and he had a tiny piece of wire wool in his eye that wasn’t picked up. It tore through his optic nerve and lost some of his sight.
Oh good lord... that's something you wouldn't even think about either going into a MRI. Yikes.
New fear unlocked
@Nelumbo_luteayou could just wear proper protective gear to keep your eye safe….
Or wait a few days. Once it's oxidized, it will have lost its ferromagneticity.
Cool story bro
I remember being a Rad Tech student years ago when my local hospital was decommissioning one of their older MRIs. They told us to hold random metal things and slowly walk towards the magnet and watch it fly.
From that day on I knew what I wanted to specialize in.
did you guys let it go and it just smashed into the MRI and just see how that went? because that sounds kinda cool
@@mixedupgirlthere is a video of people doing that here on TH-cam if you want to see
That last bit of hitting the plate was great, much better at telling how much it actually does.
I got my first MRI a few months back, in a 3 Tesla machine no less! I was so excited I had black labrador energy for days prior to the exam.
Fun fact, black labs are slightly more magnetic than other flavours because their black pigmentation is iron. It's not a *true* fact, but it is a fun one.
@@n_tas flavors?
@@pendlera2959 Hmmmm~ Black labs...
maybe he's chinese? @@pendlera2959
I once rode in a Tesla 3.
Most of the MRI companies supply a toolkit for working inside the MRI suite that is made from Titanium which is not magnetic and is not attracted to the MRI. I used to build the MRI & CT scanner suites for Lindgren.
I work in the semiconductor industry so our tools have some guidelines such as no copper, brass, silicone, galvanized steel, etc. that could contaminate wafers. Having to account for magnetism too is insane! Would love to have some of those titanium tools myself, I'll bet they're extremely light.
Do titanium tools have some sort of very obvious visual markings to let you know they're titanium?
@@haifai3916why is silicon not allowed?
@@davecrupel2817 Silicone likes to shed and become aerosolized. Once it settles onto a wafer, it can cause defects in the photolithography part of the process.
@@haifai3916 appreciate the explanation!
Yeah I definitely wouldn't want that happening.
Holy COW! I absolutely didn't expect the plate to go THAT slowly and consistently! I thought the fall would visibly accelerate!😱
Maybe if he pushed it the other way.
It's due to the fact that bodies resist change in Magnetic Flux. As the flux changes, there will be current loops formed in the aluminium plate that will create their own magnetic field, opposing the external one. Due to this, the fall slows down
If you want, try dropping rare earth magnets down a vertical piece of copper pipe.
The MRI machines used on me over the last 13 years were labelled 1.5T. I thought this was the weight in Tonnes, but I eventually realised it was the strength of the magnetic field in Tesla. 1.5 Tesla is a VERY strong magnetic field, but 7 Tesla is mind-boggling!
To be able to sustain the massive currents needed to produce those large fields, you need superconducting wires for the magnets, and those need to be cooled with liquid helium. And the liquid helium is surrounded by a jacket of liquid nitrogen for extra thermal insulation. So these magnets require constant supply of cryogenics to function.
1.5 Tesla is in fact very strong. But if you follow basic safety even stronger magnetic fields are perfectly safe. We Don't have much magnetic stuff inside our bodies (Iron bound to hemoglobin is not magnetic.)
True. Earth's magnetic field is only 0,00005 Tesla. I've been both in 1.5 and 3 T MRIs and as a non-magnetic human being, you don't really feel anything of it🤷♀️
Veritasium has a video on a 45 T magnet in florida, was definitely a fun watch
@@vidal9747imagine if haemoglobin was magnetic. the miracles that magnets perform in the medical sector would be out of reach.
Imagine how smart the people are who made this thing.
Remember when installing MRI's for Fonar in the late 80's, First saw this effect using a aluminum builders level. RIP Dr. Damadian
This is called eddy current damping where materials will resist changes in magnetic flux and is used for magnetic braking as well as vibration isolation in sensitive instruments such as the scanning tunneling microscope.
It's also the principle on which traditional speedometers worked, before they all became electronic
The part with the aluminium sheet beside the MRI machine was really interesting, you would think it was being filmed falling over in slow motion
If you liked that, you should look into people dropping magnets through copper pipes.
@@secondarycontainment4727 I've done the dropping magnets though copper any number of times. Get a length of copper from the big box store (around two feet makes for a good demostration) and I used a rare earth magnet.
Random TH-cam recommendation, but absolutely fascinating!
I looked at this because incident in Brazil when a Lawyer and gun enthusiast own personal gun was pulled from his waistband and discharged striking him while inside scan room at hospital while his mother was scanned tragic incident due to the magnetic strength of MRI magnets
That incident wasn’t due to mri, it was due to bunch of morons disregarding all mri safety rules 😂
@@samisyrjala1440 which may be true but incident was eye opener on the strength of machine. He just went for his mom appointment
Are you using the word gun advocate appropriately here
@@GeorgeSukFuk lol your right he is a gun enthusiast
"Due to MRI magnets" 😂 yes that is the root of the problem, this incident wouldn't have happened if it weren't for those darn magnets in MRIs, I think we need to start a petition to ban magnets in MRIs to prevent this from ever happening again!
THAT IS AMAZING...
Like, I knew it 'happened'.. but I never seen it actually demonstrated how intense the effect actually was..
that is a really cool demonstration of induced currents. Never seen that before :)
When I was studying engineering we had a piece of apparatus that would demonstrate eddy currents by using a motor to spin an aluminium disc, you then lower an arm that has magnets either side so that they straddle the disc, and the motor current goes up as it works harder to spin the disc as it's being braked by the magnet. It had another disc that had multiple slots cut in it which was much less affected as the currents were unable to, uh, do their thing (this was almost 20 years ago, I forgot the explanation). Cool stuff.
It's really dramatic to see that demonstration with the aluminum plate in such a strong magnetic field. There's no force when the plate is still, but when it moves, the magnetic field induces an electric current in the plate, which creates an opposing magnetic field that resists the motion. So the faster you try to make it move, the harder it resists. Cool!
What's even more amazing is that these MRI electromagnets don't need to be constantly fed power to stay magnetized, since they use superconducting coils, and retain their massive current once initially charged.
When I did the drywall work in one of them building we had to use special screws to put the sheet rock up because it will put steel screws out of the wall.
had an MRI, first ever, a couple months ago and was surprised how relaxed they were with it. He gave me a look over, said "ok you don't need to take anything off, just empty your pockets" and in my mind was "what about my zipper it's metal? as it turned out nothing was a problem but I would have thought they would have had a lot more scrutiny. Maybe I just looked a bit older so assumed I didn't have any pierced body parts under my clothes. 🤣🤣
When I had a MRI they gave me hospital scrubs, I could keep only the underpants, even bras had to be removed. When I went for a tomography I was very surprise that they just when "oh take off any jewelry if you have". I could even keep my boots! But I did feel a bit of pinching on top of my tattoo when I had the MRI, weird.
Just had mine today and had the exact same thing. The letter with the appointment made a big deal about asking you to come wearing clothes without metal buttons and zips if possible, but jeans are all I have. I asked about this and she said it should be fine, just empty your pockets. Maybe these higher rated machines it becomes more of a thing.
That's cool as heck, I'm so excited to start my MRI modality
I had to have an MRI and a 3T unit gave me immediate twitching at the top of my head. They stopped the scan due to safety concerns, and were convinced I had metal in my head despite my protestations. X-Rays and a CT Scan showed no metal, and I was fine under a 1.5T MRI. I'd hate to think what a 7T unit would do to sensitive people like me.
Maybe you had too much iron in your diet.
@@terry_willis I LOVE YOU 🤣
With hemochromatosis the body can hold more than 50g of iron, I wonder if you can feel it because of something like this
@@spiikesan an interesting thought, however my iron levels are normal.
That tap on the aluminium sheet was soo satisfying
The aluminium plate also demonstrates how modern day rollercoaster brakes work 🙂
Super cool. Would have been curious to see the copper bar as well :)
I guess the copper bar would be boring, because there is not that much space for circular currents.
As someone who works with NMR's or at least uses them everyday. This is really cool.
Another fun demonstration is get a coil of 20 turns of wire soldered to a small light bulb like for a brake light, and move it through the field. It makes it light up brightly❤
A good demonstration of how wireless charging works on cellphone and other electronics.
One coil inducing a charge in another. Only difference is, in an MRI machine, the power levels are much higher, and therefore you don’t need to be within a few mm to see the effects.
Awesome, I want to see that!
The MRI is the best thing that happened to medicine ever right after antibiotics.
Amazing machines. I had FMRI a couple times. The process is a little intimidating even if you’re not claustrophobic. Loud, too. They give you earplugs.
When I had an MRI they put a periscope-like thing in front of my eyes so I could only see the technicians working the machine, I'm not claustrophobic and was super excited to have an MRI done but the combination of being in a very confined space, feeling absolutely powerless to do anything about my current situation and the very loud and varied noises (were they good? Were they bad? Who knows!) did get my blood pumping. I was grateful to not be face to face with the machine for the duration.
I don't generally get claustrophobic or have any particular fears of this kind of thing, but when I had MRI earlier this year I did a start to feel a bit of fear after a while lying there. I'm worried that if I ever have to go in again I will freak out due to my anticipation of being scared
That's a really neat demo. Thanks.
7 TESLA? You're some elite setup.
I have been scanned on a 3T magnet before and even with the earplugs it was loud. I wonder how loud this 7T magnet gets
I wonder this too. I was in 1T and 3T. Both were fascinating and also a bit frightening. I would try the 7T if I could.
The higher RF frequency needed in a 7T magnet would be of more concern to me.
Why not? Is it super loud even with earplugs and headphones ? @@makebelievearchitect
Oh wow I thought that dizziness only happened when u sat up from being scanned. It only happened to me at 3t when I sat up and I was like woah the room is spinning and I had to lay back down and they brought a mri safe wheelchair in for me and a few minutes after I felt good enough to walk@@makebelievearchitect
@@NESig Why? For a 7T MRI machine the RF frequency is still only around 300 MHz. Afaik RF hazard doesn't really increase with frequency anyway until it becomes high enough to be able to cause ionization.... but that requires a frequency that's 10 million times higher, which would only be appropriate for an MRI machine with a 70 megatesla field ;-)
Thank you.. I GUESS ill leave my pocket scissors at home 😟
That plate looks like you‘re in a movie where you‘ve slowed down time
I love how he was hitting the plate at the end and it really wasn't changing its descent
One time I was laying half naked in an MRI for a scan of my of a tumour in my thighs and noticed a pressure being dealt on my back teeth. Turns out I forgot about the metal rings I got for my braces. Needles to say I told the doctors about it and they immediately shut the MRI off and gave me my pants back.
You cant turn off the magnets of and MRI machine.🤔
@@RogerWaringit's really the magnetic field that's the problem, not the magnet itself. The field can be disrupted.
oh you can shut it off. they have big red button for that. i bet you can hear coin bucket pouring out or cash register sounds if you press it because it's crazy expensive service call to get it all working again
This reminds me of the case here in Brazil of a man that was taking a relative for a MRI scan session. The man in question was a gun carrier. He was warned he could definitely not enter the place carrying the gun. But he was a bully and threatened staff. In the ened he entered the place with his gun in a holster hanging from his belt inside his pants. Of course the gun fired due to the magnetic force in the room hitting an artery. He died later that day. Natural selection I like to call that kind of event.
i dont know how i got here but it was oddly satisfying to watch the metal panels slowly fall without slamming
Thanks! I learned something. Does the Cu behave the same as the Al?
Cool. I always wondered about that. I had no idea that the aluminum plate would do that!?!
love the doogie howser inspired music
dang.. this was so amazing and interesting.. thank you!
The most important point is that the magnetic field is ALWAYS on, since it’s a superconducting magnet. Only way to turn off is to vent the liquid Helium keeping the magnet wires cold enough to be superconducting.
Glimpse of Magneto's superpowers.
God bless.
The pins in my skull is why i don’t have this procedure. I was once told ,it might be ok? I will not be trying to find out. CT scan is just fine thanks. Thanks for this video. It very important we know these things
This world we live in is so amazing. I can't wait to see the wonders of the next world!
God dang it, now I gotta find an MRI machine and scissors
I love the gentle science learning soundtrack
I could watch more about MRI scanners, it's fascinating....
Cool thing is that the aluminum, or the copper pipe, need to be moving to generate the electric current and subsequently generated field. Thats why it moved like molasses but the force was more resistive when he started punching it.
I was surprised to learn aluminum has any ferro/magnetic properties at all, but then I read somewhere that even wood is slightly magnetic.
Yup, all materials are diamagnetic.
@@yanikb.1312 yes, but diamagnetism does not contribute to this phenomenon. It means the material is repelled by a magnetic field, but if you lean the aluminum plate towards the magnet instead of away, it still falls instead of being pushed back the other way. Diamagnetism is so weak that it can only be measured on very small scales where all other outside forces are negligible; the phenomenon here is induced magnetism, which occurs because the material is electrically conductive.
Also, fun fact: although all materials are diamagnetic, some of them are less diamagnetic than air, and so are still weakly pushed towards the magnet by a mechanism analogous to buoyancy. On the other hand, brass has basically the same magnetic permeability as air, so it feels no force in the presence of a magnetic field, attraction or repulsion, at least not on Earth.
This has nothing to do with the aluminum being magnetic in any way. This is a result of the aluminum being electrically conductive. As a conductive element (regardless of its magnetism) moves through a magnetic field, it generates electricity. Since the plate is large/not a wire, the current loops around inside the plate. This current movement in the aluminum generates a magnetic field that counters the magnet in the mri machine. If the aluminum stops moving then there is no change in magnetism and thus the current stops and the aluminum looses its magnetism. As the aluminum falls, it is moving though the field thus generating these edie currents that slow its fall.
Any conductive material will do this. The more conductive, the stronger the affect. Thus copper is better than aluminum and silver is better than copper as it is more conductive.
@@magnuswright5572 yes I know why and how the aluminium plate falls slowly, I was referring to the part "even wood is slightly magnetic".
very impressiv.
This is a crude explanation but might provide information for some:
a. Currents create a magnetic field. (think electro magnet)
b. Changing magnetic field induces current in a conductor. (there is no current if you just have a magnet next to a conductor, the field needs to change)
as the plate tries to fall, we see (b) come into play as a current is induced. This current creates a magnetic field (a) which opposes the direction of the field that induced the current.
I will have remember to remove the scissors from my pocket, next time i go for an MRI
I had MRIs several times in my life, and one time there was a huge scratch in the "ceiling" of the tube...guess somebody forgot to take some metal off👀
I wanted to see flying scissors.
I was waiting for you to put the scissors close to the magnet 😂
I can only imagine what kind of Eddy currents there are going on in there.
Also, if it's using a DC, I'd also love to see what an AC would be like.
murphy?
I worked at a hospital for a number of years and periodically we'd have to do various safety training and one was on MRI machines. You know what they call a loose object near an MRI machine that's attracted to it? Missiles. That is the actual term for it.
The aluminium was falling slowly because of eddy current is forming inside the plate... That's producing the field which oppose the source of the produced field...
‘Jamie, put up the video of that Grizzly getting an MRI”
I had to have a MRI several years ago. Although I left my wallet in supposedly safe storage in a metal locker outside the office, I ended up having to replace every credit card that had a magnetic stripe.
That demo with the aluminum plate is actually kinda insane to watch, very surreal, good demo tho!
imagine you go for a routine scan but you forgot to mention your hip replacement
When MRI used to be called NMR but people were scared of the N, so a rebrand fixed that issue.
That's scary! So strong
I’m always a little worried that I have some sort of head injury that takes me in for an MRI unconscious, and it rips my permanent retainer out through my teeth. It’s probably titanium, but still.
I've had a tooth implant where they screw a post into the jaw and fasten the tooth to the post. Having had MRI's in the past you can bet I asked the oral surgeon. Believe he said they did use titanium and would not be an MRI problem. Had an MRI a few months ago and no problem.
7 Teslas is insane even for an MRI machine which are usually like 1.5-3
Here in Brazil, I watched this video.
A 7 Tesla Magnetom is something else !!!
I always warn MRI technicians that I have safety wire in my sternum from open heart surgery. The wire held my sternum together while it mended itself. So far it's not been a problem. 👍🏻
Please also show us the copper bar you had there. Will it stay semi-suspended?
"You will be 35 one day. You might as well be 35 and a doctor as well."
Me, 34 and still deciding if and how I should pursue med😢
Know two guys -- one age 37 and another 41 -- who chose medicine as a second career. Both are terrific doctors now!
He tapped on the slowly falling aluminum plate but didn't hasten it's fall. How cool is that!
Such an amazing invention.
And its development by two different and independent inventors (and the subsequent legal issues) is a good story, too! 😎✌️
About 6 years ago a IV pole got snatched up to an MRI machine, broke the plastic around the opening of the machine, bruised the patients leg pretty good. I am a nurse, but it was my patient that it happened to and boy that was a mess.
That aluminum plate is a 'paid actor'.
now I know how Neo stopped those bullets... he created a massive amount of magnetic force...
Do you have to release the helium gas to release the MRI magnet?
Prank your doctor by swallowing some coins before your MRI
great demo!
guess that explains the weird pulling sensations i get inside me when im in the MRI. your blood does have iron in it still which is a ferrous metal.
A copper plate of the same size would have looked even more impressive.
I believe that's just a lot of Gauss
I worked in a Aluminiumfactory, I know that on the negative site of the stove the welders had to weld a Aluminium bar against a other bar.in the factory there is also a magnetic field,the welders could not weld normal,because the liquid aluminium flew away from the bar.they had to put a steel construction around the weldingplace.Also a very strange thing to see😅
What about the copper piece? No showing what it does?
Even though they didn't show it, I can at least say copper has a stronger response which is why it's a common material used for eddy current damping in many scientific instruments.
What happens if you bring 24k gold near it? What about something diamagnetic like silver?
I used to do that with a quarter as a demonstration.
note to self, don't ever forget you have a small piece of shrapnel in your leg.
A demonstration of Lenz's law developed by Emil Lenz in 1834.
Seen a truck driver throw a pair of bolt cutters in the back of a mobile MRI. They shot through one end out the other and back again. A few hundred thousand dollars of damage in a few seconds. He then had to drive 24 hours back with the MRI he just broke.
People with permanent retainers: 😳
As someone who's always been into dangerous/extreme activities, and being a 2 x cancer 'survivor',
I've had to do a handful or so MRIs so far.. The effects / after-effects have been interesting..
My left arm was fully tattooed / full color / lots of 'red' pigment used..
Interesting fact: Some tattoo inks are made by using 'iron oxide' aka 'rust' [i.o. / rust = red in color]
At the time of the MRI scans, I'd always notice a slight and I mean Very slight 'tingle' on that arm..
Well.. That would be because the electromagnetic field was literally pulling the stuff outa' my skin!
Looking at the arm/tattoo Now, the areas that Used To Be red are now just regular skin again..
On the flip side, I have a few piercings w/ med grade stainless steel rings that where non-effected..
They tried their best to make me take them out, buuut.. that wasn't about to happen.
[luckily, the scan[s] didn't turn me into a eunuch 🤣]
So if you did that with a large aluminum ball would it drop down slowly?
No, but it might not drop in a straight path. It'll fall along the field lines.
That is pretty cool
The aluminum plate will also get warm from the eddy currents induced in it by the magnetic field.
How does the magnetic force have any effect on aluminum?
Is there anyway that the field could strip the iron out of your blood cells and any other area in the body that iron might be stored in?
Nah.
I knew but I had no idea.
I had an idea, but I didn't knew.