Safety first
A lot of people seem to be sharing the story about the guy who died in Mubai from an MRI accident. I figured I should clear up a few things because all of the stories I’ve seen so far have a lot of mistakes.
There’s no way liquid oxygen is involved. He died from his chest getting significant trauma from the oxygen cylinder. I’ve never heard of someone dying from breathing in too much pure oxygen (except divers, premature babies, etc.) I’ll grant that it is possible if he was stuck there for a long time. However, I’m assuming that the patient had a small portable E cylinder, not the H size cylinders that you might see welders use.
The magnet didn’t quench so he was not breathing helium (from the boiling liquid helium). You can certainly die of asphyxiation when a super-conducting magnet quenches but that’s not what happened. This article said that the cylinder was still there the next day. https://goo.gl/aHCaZz
Patient oxygen cylinders are almost always steel, and heavy iron steel at that, not stainless steel. If a patient needs oxygen, they often have tubes going into the MRI room so that the gas cylinder can be a safe distance away, most likely in a “tank closet”. A tank closet has many cylinders with a monitoring system that automatically switches from an empty cylinder to a full one. Many hospitals actually have huge liquid oxygen storage tanks outside and pump gaseous oxygen throughout the building into patient rooms, operating rooms, etc. Whoops, let’s get back on track.
MRI magnets ARE ALWAYS ON. We have a sign on the door for maintenance, janitorial, and emergency personnel. When you turn the MRI “off”, i.e., ramp down the magnetic field, it’s a slow, deliberate process. One of our MRI scanners has a liquid helium regenerating system. We ramp down the field every two years to replace that system. It has to be done very carefully and slowly. You also tend to lose liquid helium in the process. So turning an MRI “off” would be expensive.
This story reminds me of the website that collects MRI accident images.
http://www.simplyphysics.com/flying_objects.html
I hope Lacerant Plainer has a better article to point me to but here’s what I have so far.
Mumbai MRI accident: Ward boy told us machine was switched off, said relative of deceased
Hindustan Times
Image source:
https://radiologykey.com/wp-content/uploads/2016/01/c17-fig-0003.jpg
For background on MRI and CT see my #CHMedicalImagingSeries
Medical Imaging 101 pt 3: MRI
What is MRI quenching, you ask? Read more here:
Looks like that bottle was in quite the hurry getting to that spot inside the MRI. I’m pretty sure that if a person was in the way, it would do similar damage to whatever body part it hit….
Valdis Klētnieks I’ve seen small item go into the magnet (tweezers, paperclip). It’s fast enough that you can’t see it “fly”.
What’s weird is that when I read this story… I thought “I bet Chad has an opinion or two on this.”
Ray of Sunshine I bet you did and I bet you are correct.
That other site…I think it may have even been a Gizmodo post…
The facepalms just in reading the initial report.
Plus I associate you as the medical imaging machine gawd.
Ray of Sunshine you probably meant to say medical imaging guy.
Thanks for clarifying… 🙂
None of the articles I’ve read offer a ton of detail; they seem to all be based on one original report.
This one, ostensibly written from an engineering perspective, has a tad more detail.
I did find a chilling account of a grisly incident involving an oxygen tank in my travels, but in that case, a child was hit in the head by a ‘flying’ tank~ whereas this latest accident seems to either involve the patient having been ‘sucked up’ into the inner workings of the MRI scanner, or pneumothorax due to?
[this article reads: Preliminary autopsy reports suggest that the man inhaled liquid oxygen from the leaking cylinder, which led to the death, the scenario you’ve just debunked, thank you…]
This report further states that the man’s hand got stuck between the machine and cylinder and further efforts to pull him to the safety resulted in a massive oxygen leak.
Which is different from ‘being sucked up into’; so I’m a bit confused.
Could you speak to how one might get ‘pinned’ or ‘trapped’ within a scanner {beyond being ‘attached’ to the metal tank and traveling along with it, or being pinned between it and the?} +Chad Haney, or what they mean?
I’ve had several scans, and can’t picture a segment of the machine large enough to be ‘sucked up’ into, but then again, I’ve only experienced MRIs from the typical patient ‘perspective’.
I appreciate your know-how!
interestingengineering.com – Indian Man Loses His Life After Getting Sucked into MRI Scanner
rare avis Possibly adding to what happened is that magnetism follows an inverse-square law. The upshot is that you feel only a slight tug on the oxygen cylinder, walk halfway to the machine and it’s only a bit more, but then it ramps up quickly, to the point where you blink and you’re pinned to the machine by the cylinder like a kid’s artwork on a fridge.
I could easily see an oxygen cylinder being enough to break some ribs – which could be “Game Over” for somebody who’s already so respiratory challenged that they carry an oxygen with them….
Valdis Klētnieks It falls off even faster than inverse-square, because there are no isolated current segments, and fields outside the magnet tend to cancel one another as you get further away. Which would make it even more of a nasty surprise.
Valdis Klētnieks it was the “old” man’s ward that was killed, not the person who needed the oxygen cylinder.
In addition to what Matt McIrvin said, many high field magnets have active shielding. So the gradient from “hey something is going on” to “holy crap, what happened” is very small.
I was shocked when I read about the incident in the news, and thought it was due to the hospital’s negligence with the machine, and could very well happen in Sri Lanka! Thanks for the post which explains what could have happened, Chad Haney
Siromi Samarasinghe the doctor and technician were arrested for negligence. They should have never said that the magnet was off.
rare avis “sucked up/into” the MRI scanner is a poor choice of words. I think they are implying that he got pinned very, very quickly.
Robert Pratt I’m not sure I get where you are going with your comment. These types of accidents happen here in the USA. I’m guessing in the USA or Europe, someone would have hit the emergency quench button to free the man. I think my digression about liquid oxygen lead you astray.
Robert Pratt there was a doctor and technician that told the patient’s helper/ward that it was safe to bring the oxygen cylinder in with the patient. There’s no infrastructure issue, just negligence regarding “the MRI isn’t on”.
Damage to the MRI machine, never mind the cost of shutting down to remove the foreign object and the loss of use for a while: quite a lot more than that, I’d expect.
Robert Pratt in every major western hospital patients walk around with oxygen bottles. Hooked to the wall is for when you’re in the bed. Or in an MRI room.
Robert Pratt anddddd……
My point was that oxygen bottles are not unique to non-western hospitals. Try making fewer racist comments.
This story was shocking and it pop up on my phone as I was starting my new job at an MRI department yesterday. It was poorly written in thr article I initially read. Thank you for clarifying it. +Chad Haney
I read a news story, thanks for the added context.
As a occasional professional failure analyst, I would toss in that “human error” is rarely an effective attribution. Usually you can point to something outside one person (like hardware, procedures, training) that allowed predictable human error to cause a failure. Blaming a person is a way to say “the person has been removed, so we’re good.” And when I stop at that, it means I’m accepting future failures — lethal failures here — to occur when this type of human error occurs. Do I know what rate that is, that I’m accepting?
But that’s general philosophy, and I don’t know the specific safeguards that imaging departments use to keep fatality rate lower than human mistake rate.
Jasper Janssen I was trying to make the same point, regarding oxygen cylinders that a lot of elderly people have (regardless of geographic location).
Huh that article adds a lot more detail. Pneumothorax. I had also assumed it was a hospital employee, not a patient or relative. That the ward boy would say that in front of the tech and doctor and not be corrected, that’s where the whole problem came in. That’s why they are in trouble.
Chad Haney nah…there are medical imaging guys, and then there’s Chad.
Don’t be so modest. Take a compliment.
Ray of Sunshine right?
I appreciate you using your expertise to clear up misconceptions about MRI.
Also, I have a foot full of surgical pins and it’s currently twitching while I think about MRIs. Is titanium affected by magnetism? I should check. I think I’m an all titanium cyborg, at least.
Gretchen S. titanium is OK in most cases. For some scans, any metal, like under wire bras, can heat up.
And old shitty orthopedic implants hurt like a Mofo when in the MRI.
Chad Haney Eeeeerg.
Wowwww 😳
You have to study for many years to be a doctor he gives the diagnois and recommend what kind of treatment is best for the clients or patients situation