7 ms·

> "I'm saying, 'Could you turn off the machine? Call 911. Do something. Turn this damn thing off!'" [pleaded the victim's wife]. The journalist missed a golde

> "I'm saying, 'Could you turn off the machine? Call 911. Do something. Turn this damn thing off!'" [pleaded the victim's wife]. The journalist missed a golden opportunity for education here: most MRI scanner magnets cannot be turned off like that. For the few that can, it's going to cost >$50,000 just to refill the liquid helium, not to mention the real and opportunity costs associated with rendering the machine offline for days or weeks. If people don't know about the magnet, or don't know that it can't be turned off (or perhaps assume it's "off" because the scan was over, as I would guess happened here), accidents happen.

DanielleMolloy 1y ago
MRI techs do not think about it cost when life is at danger. If someone is in life danger due to the magnet, you quench. This is standard MRI education. I think the big question here is why they didn’t..
Aeolun 1y ago
You are going to have to turn it off if there’s a body attached to your machine too, so that’s not much of a lost opportunity.
deleted 1y ago
[deleted]
josephcsible 1y ago
> most MRI scanner magnets cannot be turned off like that. For the few that can, it's going to cost >$50,000 just to refill the liquid helium, not to mention the real and opportunity costs associated with rendering the machine offline for days or weeks. I thought these days, most MRIs did have an emergency quench button.
- jpgvm 1y ago
  Yeah I would say all modern MRIs do. However one misconception is that loss of field strength is instantanous, it's not. The field strength drops off over about 15s or so as the helium boils off and the magnet losses superconducting properties. So the emergency quench is less useful than it sounds in these situations... it's very likely if an MRI is going to kill you it's going to do it fast enough for it not to be relevant.
  - Doxin 1y ago
    Surely you'd hit the quench button straight away? I cannot imagine policy being "check if the victim is dead, and if not hit the button." I also wonder what the field decay is like. If it takes 15s and it's linear it's much worse than if it's 15s but decays exponentially. You don't need to field to be gone, you need the field to diminish enough to stop strangling the poor guy.
    - potato3732842 1y ago
      Takes more than 15sec to strangle someone. 30 shouldn't cause any serious damage beyond whatever mechanical damage there is from being tugged around. Heck, 2-3min is probably fine if the MRI is located at a hospital. Edit: Per the article that I would like to remind everyone is well worth reading, he had time to say goodbye to his wife, that would seem to me to imply he wasn't tossed hard enough to be incapacitated.
      - baq 1y ago
        strangle? dude's neck was probably crushed. if I had to guess this was a near decapitation, not a strangling.
        Doxin 1y ago
        honestly, probably, yeah, but the guy running the MRI can't know that and should have quenched immediately. You don't just go "oh well he's probably dead, nothing I can do about it now."
        baq 1y ago
        my point is even if he had quenched ASAP the damage might've been done already.
      - close04 1y ago
        Causing severe head trauma or crushing the trachea can be almost instant. A lot of the more serious MRI related injuries are objects flying across the room and hitting someone, especially over the head.
- lostlogin 1y ago
  After GE got their shit together, yes. https://www.diagnosticimaging.com/view/everything-you-need-know-about-ge-mri-recall https://www.diagnosticimaging.com/view/everything-you-need-k...
daft_pink 1y ago
I’m pretty sure when some guy gets sucked into the machine, the downtimes/lawsuits/etc and pressing the emergency button and having a ton of down time is a sunk cost at that point and you are basically obligated to do everytyhing you can to avoid catastrophe to reduce your legal peril.
- fnordpiglet 1y ago
  There’s also the basic idea that a human life is worth saving. The money can be figured out later. Sadly though the magnetic fields of an MRI don’t disappear by simply powering the machine down. It can take a while even then. The fact a man with an enormous iron chain is allowed to walk into the room under any circumstance is where the lawsuits will come from, and rightly so.
sapiogram 1y ago
> For the few that can, it's going to cost >$50,000 just to refill the liquid helium In this case, they were going to have to do that anyway. Might as well shut it down right away.
- Insanity 1y ago
  Fair, but these are split-second decisions and they likely didn't have a lot of time to react.
- Aurornis 1y ago
  An emergency quench of the magnet takes about 1-2 minutes. There isn’t a way to instantly turn it off.
  - mdavid626 1y ago
    Isn’t 2 minutes enough?
    - egberts1 1y ago
      Nope. Because the crushing action literally rendered his neck beyond surgical repair.
  - CoastalCoder 1y ago
    Does that energy basically turn into heat because the superconductors start to have electrical resistance? If so, I'm curious if that heat causes additional damage to the machine, necessitating a refurbishing or at least some parts replacement.
    - userbinator 1y ago
      I believe all that heat goes into boiling off the helium keeping it cool.
  - cvoss 1y ago
    All the more reason to push the button immediately.
littlestymaar 1y ago
> most MRI scanner magnets cannot be turned off like that. For the few that can, it's going to cost >$50,000 just to refill the liquid helium, I now nothing about MDI so please tell me: why does it need to refuel the helium? Aren't the magnets “just” superconductive electromagnets? Why can't the current powering the magnet be stopped? Edit: thanks everyone for your explanations, I appreciate it.
- fivestones 1y ago
  For what it’s worth I just learned this from chatgpt. But the magnet is a superconducting electromagnet, and it’s started up by cooling the superconducter to around 4 Kelvin, and then electricity is turned on, and then once it’s going at the desired current, there is some kind of superconducting switch that disconnects the power source. After that no more power is supplied to the magnet—it will run with that same current for years, as long as you keep it cold enough to be super conducting. Apparently the resistance is actually truly zero, not just almost zero. So there is no current to turn off. The current in the magnet is running on its own from when it was first supplied. The only way to stop it is to heat up the superconductor. I thought maybe you could draw it off and use it up somewhere else, but then if I’m remembering right electricity will always take the last of least resistance, so none of it would leave a superconductor. Right? It also makes me wonder, if someone is ever able to build a warm superconductor, how would we ever stop electricity we’ve put into a system like that?
  - snypher 1y ago
    There is some small losses, it does not run 'forever'. However the superconducting switch is pretty neat. It's a small section of superconductor between the ends of the coil, but is wrapped in a heating element. When the coils is first powered up the element is heated and the material has a resistance. When the coil is ready the heating element is turned off and the shorted conductor cools down and starts superconducting.
  - littlestymaar 1y ago
    > For what it’s worth I just learned this from chatgpt. Why the hell are people doing that over again? Nobody asked you to copy-paste a plausible AI-generated response you have no idea about its accuracy. That some people like do it is depressing, but the fact that you are bragging about that is truly beyond words.
Symmetry 1y ago
In the US the federal government uses numbers around $10 million for the statistical value of a human life when doing cost benefit analysis for various programs or interventions. Any sort of lifesaving medical care can easily come in at more than $50,000. The operators shouldn't be hesitating to shut down that machine to save someone's life, and I would be willing to be that they are trained to do so.
- elaus 1y ago
  Now you are at the Trolley problem: shut down the machine to (maybe) save one person, but preventing all MRIs for the next x weeks, causing y indirect deaths?
  - drbscl 1y ago
    You're not exactly going to be running many scans with a human corpse stuck in the MRI machine...
  - ashtonbaker 1y ago
    It'll need to be shut down anyway to pull the giant metal chain out. You might as well do it right away. Patients can and will be rescheduled to other MRI facilities.
  - swat535 1y ago
    I'm not sure how this is a Trolley problem? It's a logistics and legislation problem. Hospitals need to be adequately prepared for emergencies and handle backups. I think a death machine that can't be stopped is an issue.
  - cvoss 1y ago
    The Trolley problem is only a problem because there is perfect information in the hypothetical about the consequences of your actions. In real life, you have far less information to go on, which often leads to a more obvious right answer. Shutting down the machine to try to save the one person right in front of you that you know is in immediate danger is the right answer, versus the far less knowable hypothetical future where some number of people may or may not have delayed or relocated scans which may or may not have delayed treatment that may or may not have been immediately necessary as a life-saving matter. As a private MRI operator, you are not morally responsible for keeping your machine functional in order to help keep (figurative) passers-by alive. But you are morally responsible for the health and safety of the patients and visitors on your premises.
chrisandchris 1y ago
> The journalist missed a golden opportunity for education here: most MRI scanner magnets cannot be turned off like that. Thanks for that - and it reminded me of the sad state media is today. I read the same story in about 4 papers and nowhere was written _why_ they couldn't turn off the machine. Miss the days where journalists actually read what they have written.
hn_user82179 1y ago
That's a huge deal. I read the article and assumed the machine was mistakenly thought to be turned off or was "winding down". That's especially frustrating as the patient seems to be blaming the hospital staff for the incident.
- foo-bar-bat 1y ago
  The patient would be 100% correct to blame the hospital staff for this incident. The only possible explanation is human error by the staff. The only reason this doesn't happen every day in hospitals around the world is MRI staff are not incompetent.
DebtDeflation 1y ago
If anyone is curious what pushing the button to turn off (AKA "quench) the magnet looks like, there's this video of an MRI machine being decommissioned: https://www.youtube.com/watch?v=9SOUJP5dFEg https://www.youtube.com/watch?v=9SOUJP5dFEg You push the button, then 15 seconds later the liquid helium is vented through a pipe on the roof of the hospital (it's quite a spectacular display), and then the superconductor starts to heat up and no longer be a superconductor so the current that's been flowing through the coils (they are energized once, when the machine is first installed, and then continue flowing forever so long as the superconductor is superconducting since there's no resistance) and the magnetic field decays to nothing. It's not an instantaneous process.
- foo-bar-bat 1y ago
  This is only comment in this entire thread that's worth reading.
- egberts1 1y ago
  A video of ejection of vaporized liquid helium out of a smokestack at a hospital performing a quench of their MRI machine. https://m.youtube.com/watch?v=h-aLlSi4Rv0 https://m.youtube.com/watch?v=h-aLlSi4Rv0
Aurornis 1y ago
The cost isn’t the issue. Quenching the magnet takes up to several minutes. There are also alarms to warn people to get away because the rapidly expanding helium could displace oxygen in the room. It’s not about the cost. If there’s an emergency that necessitates pressing the button they’ll be pressing it as soon as someone can reach it. It still takes time for the magnetic field to dissipate.
- rzzzt 1y ago
  What sort of decay curve can you plot from the magnetic field dissipating over time? Is it linear?
  - throwawayffffas 1y ago
    Not a physist, but I remember from school when studying electrical resonators, the stronger the inductor the lower the resonant frequency. i.e. the stronger the magnetic field the longer it takes to turn back into current. I would guess a strong magnet takes a while, probably minutes to shed its field.
    - adastra22 1y ago
      This is a superconductor. It is basically on full strength until it suddenly isn't.
      - throwawayffffas 1y ago
        In the idealized resonator, the impedance is assumed zero what matters is the inductor strength and the capacity in the capacitor. In a real MRI, I presume there is no capacitor to take the charge, I am guessing the limiting factor is the impedance of wherever the charge is going to go.
      - privatelypublic 1y ago
        Saturation/critical current: zero resistance doesn't mean infinite current. all superconductors gain resistance if the current exceeds a value. This value is temperature dependent.(http://hyperphysics.phy-astr.gsu.edu/hbase/Solids/scbc.html http://hyperphysics.phy-astr.gsu.edu/hbase/Solids/scbc.html).
Grustaf 1y ago
$50,000 seems like a pretty cheap price for saving a life though.
- egberts1 1y ago
  $50,000 only to find that affected areas are beyond surgical repair due to 3,200 lbs/ft crushing at 16 G-force at wall-impact point.
lostlogin 1y ago
They can be quenched (as you note), but there was that one time that GE didn’t connect the quench button to prevent accidental/expensive usage and n India, and someone died. Surprise! It turns out there is a reason it should be connected. https://www.diagnosticimaging.com/view/everything-you-need-know-about-ge-mri-recall https://www.diagnosticimaging.com/view/everything-you-need-k...

DanielleMolloy 1y ago

MRI techs do not think about it cost when life is at danger. If someone is in life danger due to the magnet, you quench. This is standard MRI education. I think the big question here is why they didn’t..

Aeolun 1y ago

You are going to have to turn it off if there’s a body attached to your machine too, so that’s not much of a lost opportunity.

deleted 1y ago

[deleted]

josephcsible 1y ago

> most MRI scanner magnets cannot be turned off like that. For the few that can, it's going to cost >$50,000 just to refill the liquid helium, not to mention the real and opportunity costs associated with rendering the machine offline for days or weeks. I thought these days, most MRIs did have an emergency quench button.

jpgvm 1y ago
Yeah I would say all modern MRIs do. However one misconception is that loss of field strength is instantanous, it's not. The field strength drops off over about 15s or so as the helium boils off and the magnet losses superconducting properties. So the emergency quench is less useful than it sounds in these situations... it's very likely if an MRI is going to kill you it's going to do it fast enough for it not to be relevant.
- Doxin 1y ago
  Surely you'd hit the quench button straight away? I cannot imagine policy being "check if the victim is dead, and if not hit the button." I also wonder what the field decay is like. If it takes 15s and it's linear it's much worse than if it's 15s but decays exponentially. You don't need to field to be gone, you need the field to diminish enough to stop strangling the poor guy.
  - potato3732842 1y ago
    Takes more than 15sec to strangle someone. 30 shouldn't cause any serious damage beyond whatever mechanical damage there is from being tugged around. Heck, 2-3min is probably fine if the MRI is located at a hospital. Edit: Per the article that I would like to remind everyone is well worth reading, he had time to say goodbye to his wife, that would seem to me to imply he wasn't tossed hard enough to be incapacitated.
    - baq 1y ago
      strangle? dude's neck was probably crushed. if I had to guess this was a near decapitation, not a strangling.
      - Doxin 1y ago
        honestly, probably, yeah, but the guy running the MRI can't know that and should have quenched immediately. You don't just go "oh well he's probably dead, nothing I can do about it now."
        baq 1y ago
        my point is even if he had quenched ASAP the damage might've been done already.
    - close04 1y ago
      Causing severe head trauma or crushing the trachea can be almost instant. A lot of the more serious MRI related injuries are objects flying across the room and hitting someone, especially over the head.
lostlogin 1y ago
After GE got their shit together, yes. https://www.diagnosticimaging.com/view/everything-you-need-know-about-ge-mri-recall https://www.diagnosticimaging.com/view/everything-you-need-k...

daft_pink 1y ago

I’m pretty sure when some guy gets sucked into the machine, the downtimes/lawsuits/etc and pressing the emergency button and having a ton of down time is a sunk cost at that point and you are basically obligated to do everytyhing you can to avoid catastrophe to reduce your legal peril.

fnordpiglet 1y ago
There’s also the basic idea that a human life is worth saving. The money can be figured out later. Sadly though the magnetic fields of an MRI don’t disappear by simply powering the machine down. It can take a while even then. The fact a man with an enormous iron chain is allowed to walk into the room under any circumstance is where the lawsuits will come from, and rightly so.

sapiogram 1y ago

> For the few that can, it's going to cost >$50,000 just to refill the liquid helium In this case, they were going to have to do that anyway. Might as well shut it down right away.

Insanity 1y ago
Fair, but these are split-second decisions and they likely didn't have a lot of time to react.
Aurornis 1y ago
An emergency quench of the magnet takes about 1-2 minutes. There isn’t a way to instantly turn it off.
- mdavid626 1y ago
  Isn’t 2 minutes enough?
  - egberts1 1y ago
    Nope. Because the crushing action literally rendered his neck beyond surgical repair.
- CoastalCoder 1y ago
  Does that energy basically turn into heat because the superconductors start to have electrical resistance? If so, I'm curious if that heat causes additional damage to the machine, necessitating a refurbishing or at least some parts replacement.
  - userbinator 1y ago
    I believe all that heat goes into boiling off the helium keeping it cool.
- cvoss 1y ago
  All the more reason to push the button immediately.

littlestymaar 1y ago

> most MRI scanner magnets cannot be turned off like that. For the few that can, it's going to cost >$50,000 just to refill the liquid helium, I now nothing about MDI so please tell me: why does it need to refuel the helium? Aren't the magnets “just” superconductive electromagnets? Why can't the current powering the magnet be stopped? Edit: thanks everyone for your explanations, I appreciate it.

fivestones 1y ago
For what it’s worth I just learned this from chatgpt. But the magnet is a superconducting electromagnet, and it’s started up by cooling the superconducter to around 4 Kelvin, and then electricity is turned on, and then once it’s going at the desired current, there is some kind of superconducting switch that disconnects the power source. After that no more power is supplied to the magnet—it will run with that same current for years, as long as you keep it cold enough to be super conducting. Apparently the resistance is actually truly zero, not just almost zero. So there is no current to turn off. The current in the magnet is running on its own from when it was first supplied. The only way to stop it is to heat up the superconductor. I thought maybe you could draw it off and use it up somewhere else, but then if I’m remembering right electricity will always take the last of least resistance, so none of it would leave a superconductor. Right? It also makes me wonder, if someone is ever able to build a warm superconductor, how would we ever stop electricity we’ve put into a system like that?
- snypher 1y ago
  There is some small losses, it does not run 'forever'. However the superconducting switch is pretty neat. It's a small section of superconductor between the ends of the coil, but is wrapped in a heating element. When the coils is first powered up the element is heated and the material has a resistance. When the coil is ready the heating element is turned off and the shorted conductor cools down and starts superconducting.
- littlestymaar 1y ago
  > For what it’s worth I just learned this from chatgpt. Why the hell are people doing that over again? Nobody asked you to copy-paste a plausible AI-generated response you have no idea about its accuracy. That some people like do it is depressing, but the fact that you are bragging about that is truly beyond words.

Symmetry 1y ago

In the US the federal government uses numbers around $10 million for the statistical value of a human life when doing cost benefit analysis for various programs or interventions. Any sort of lifesaving medical care can easily come in at more than $50,000. The operators shouldn't be hesitating to shut down that machine to save someone's life, and I would be willing to be that they are trained to do so.

elaus 1y ago
Now you are at the Trolley problem: shut down the machine to (maybe) save one person, but preventing all MRIs for the next x weeks, causing y indirect deaths?
- drbscl 1y ago
  You're not exactly going to be running many scans with a human corpse stuck in the MRI machine...
- ashtonbaker 1y ago
  It'll need to be shut down anyway to pull the giant metal chain out. You might as well do it right away. Patients can and will be rescheduled to other MRI facilities.
- swat535 1y ago
  I'm not sure how this is a Trolley problem? It's a logistics and legislation problem. Hospitals need to be adequately prepared for emergencies and handle backups. I think a death machine that can't be stopped is an issue.
- cvoss 1y ago
  The Trolley problem is only a problem because there is perfect information in the hypothetical about the consequences of your actions. In real life, you have far less information to go on, which often leads to a more obvious right answer. Shutting down the machine to try to save the one person right in front of you that you know is in immediate danger is the right answer, versus the far less knowable hypothetical future where some number of people may or may not have delayed or relocated scans which may or may not have delayed treatment that may or may not have been immediately necessary as a life-saving matter. As a private MRI operator, you are not morally responsible for keeping your machine functional in order to help keep (figurative) passers-by alive. But you are morally responsible for the health and safety of the patients and visitors on your premises.

chrisandchris 1y ago

> The journalist missed a golden opportunity for education here: most MRI scanner magnets cannot be turned off like that. Thanks for that - and it reminded me of the sad state media is today. I read the same story in about 4 papers and nowhere was written _why_ they couldn't turn off the machine. Miss the days where journalists actually read what they have written.

hn_user82179 1y ago

That's a huge deal. I read the article and assumed the machine was mistakenly thought to be turned off or was "winding down". That's especially frustrating as the patient seems to be blaming the hospital staff for the incident.

foo-bar-bat 1y ago
The patient would be 100% correct to blame the hospital staff for this incident. The only possible explanation is human error by the staff. The only reason this doesn't happen every day in hospitals around the world is MRI staff are not incompetent.

DebtDeflation 1y ago

If anyone is curious what pushing the button to turn off (AKA "quench) the magnet looks like, there's this video of an MRI machine being decommissioned: https://www.youtube.com/watch?v=9SOUJP5dFEg https://www.youtube.com/watch?v=9SOUJP5dFEg You push the button, then 15 seconds later the liquid helium is vented through a pipe on the roof of the hospital (it's quite a spectacular display), and then the superconductor starts to heat up and no longer be a superconductor so the current that's been flowing through the coils (they are energized once, when the machine is first installed, and then continue flowing forever so long as the superconductor is superconducting since there's no resistance) and the magnetic field decays to nothing. It's not an instantaneous process.

foo-bar-bat 1y ago
This is only comment in this entire thread that's worth reading.
egberts1 1y ago
A video of ejection of vaporized liquid helium out of a smokestack at a hospital performing a quench of their MRI machine. https://m.youtube.com/watch?v=h-aLlSi4Rv0 https://m.youtube.com/watch?v=h-aLlSi4Rv0

Aurornis 1y ago

The cost isn’t the issue. Quenching the magnet takes up to several minutes. There are also alarms to warn people to get away because the rapidly expanding helium could displace oxygen in the room. It’s not about the cost. If there’s an emergency that necessitates pressing the button they’ll be pressing it as soon as someone can reach it. It still takes time for the magnetic field to dissipate.

rzzzt 1y ago
What sort of decay curve can you plot from the magnetic field dissipating over time? Is it linear?
- throwawayffffas 1y ago
  Not a physist, but I remember from school when studying electrical resonators, the stronger the inductor the lower the resonant frequency. i.e. the stronger the magnetic field the longer it takes to turn back into current. I would guess a strong magnet takes a while, probably minutes to shed its field.
  - adastra22 1y ago
    This is a superconductor. It is basically on full strength until it suddenly isn't.
    - throwawayffffas 1y ago
      In the idealized resonator, the impedance is assumed zero what matters is the inductor strength and the capacity in the capacitor. In a real MRI, I presume there is no capacitor to take the charge, I am guessing the limiting factor is the impedance of wherever the charge is going to go.
    - privatelypublic 1y ago
      Saturation/critical current: zero resistance doesn't mean infinite current. all superconductors gain resistance if the current exceeds a value. This value is temperature dependent.(http://hyperphysics.phy-astr.gsu.edu/hbase/Solids/scbc.html http://hyperphysics.phy-astr.gsu.edu/hbase/Solids/scbc.html).

Grustaf 1y ago

$50,000 seems like a pretty cheap price for saving a life though.

egberts1 1y ago
$50,000 only to find that affected areas are beyond surgical repair due to 3,200 lbs/ft crushing at 16 G-force at wall-impact point.

lostlogin 1y ago

They can be quenched (as you note), but there was that one time that GE didn’t connect the quench button to prevent accidental/expensive usage and n India, and someone died. Surprise! It turns out there is a reason it should be connected. https://www.diagnosticimaging.com/view/everything-you-need-know-about-ge-mri-recall https://www.diagnosticimaging.com/view/everything-you-need-k...