MRI Room

[mannyb]

We are building an MRI facility. They will test the MRI but will have an emergency run down button for emergency. Does anyone have any experience with this type of install. Is this basically a shunt trip to breaker. we are at beginning stages of construction but I would like to know a little before I would start. if you have any pics or information please share.

 

[kwired]

Did a CT room once, IIRC they wanted basically a E-stop style button that operated a shunt trip breaker in the main supply to the X-ray generator. I think we put one near the operator's station and one next to the entry door to the room. I don't know what any codes would require especially non NEC codes, but I think the equipment reps basically designed that and made the specifications for that install, I just put in what they asked for.

I would guess the "E-stop" for MRI would be somewhat similar. I don't think an operator would normally be in the room when MRI is active, so a station in the room may or may not be required, but I would think a station near the operator would be required.

From what I have heard about MRI is they calibrate the machine to the room, only thing that changes is the presence of the patient to be examined. Nobody enters room once a session is started or while in progress nor do they change any contents of the room or it can throw things off.

If there is an emergency and MRI needs stopped, I think it must be stopped before anybody enters the room. If so I could even see a door switch that disables the unit if the door is opened being a requirement.

 

[Jamesco]

We are building an MRI facility. They will test the MRI but will have an emergency run down button for emergency. Does anyone have any experience with this type of install. Is this basically a shunt trip to breaker. we are at beginning stages of construction but I would like to know a little before I would start. if you have any pics or information please share.

Emergency run down button? You need to ask more questions what the button controls. Check the drawings. Check with the MRI equipment manufacturer's engineer.

 

[hbiss]

From what I understand the E stop for an MRI dumps the liquid helium and you don't want to be around when that happens. There is always a pipe up through the roof to direct the tremendous amount of vapor outside. Dumping the liquid helium (almost 750 gallons) is the only way to kill the magnet if that should become necessary like something getting drawn into it. It's a superconducting electromagnet. Once it's cooled down by the liquid helium to -452 deg F it has zero resistance. So if you pass a current through it then short the leads (also in the helium so the short is zero resistance) the magnet will stay up for maybe 6 months all by itself. Then you "goose" it again with more current, I guess.

Google "MRI magnet quench". Sometimes all does not go well and the thing explodes. Yup, hitting that button is a serious proposition!

-Hal

 

[Jamesco]

I assume the magnet is not a permanent magnet type.

http://mriquestions.com/emergency-stop-button.html

 

[hbiss]

It's an electromagnet and once charged, it requires no additional power. As long as it's kept in a superconducting state it will remain a magnet. There is no permanent magnet on earth that can come anywhere close to the strength of it.

-Hal

 

[Jamesco]

It's an electromagnet and once charged, it requires no additional power. As long as it's kept in a superconducting state it will remain a magnet. There is no permanent magnet on earth that can come anywhere close to the strength of it.

-Hal

https://radiopaedia.org/articles/magnets-types?lang=us

 

[hbiss]

See Superconductive MRI magnets

As far as I know MRIs that are able to use permanent magnets are still in their infancy.

-Hal

 

[Jamesco]

See Superconductive MRI magnets

As far as I know MRIs that are able to use permanent magnets are still in their infancy.

-Hal

Don't know one way or the other.

The only MRI magnet that I have any experience with is a high field superconductive magnet type.

I would imagine a permanent magnet type MRI would be a low field type.

Jim

 

[hbiss]

That's what I know also.

-Hal

 

[Jamesco]

The MRI unit I first dealt with was made by Picker. I was involved in
up-grading it several times over the years. The Last time I was involved with the room, the Picker unit was replaced with a GE unit. That required a new magnet. What a job that turned out to be. Clearing a path several hundred feet through the hospital to get the old magnet out and the new one in.

.

There are two emergency buttons for the MRI unit.

One for the MRI Imaging room to quench the system demagnetizing the magnet. (The button is installed a clear plastic enclosure with a hinged door that lifts from the bottom giving access to the button.)

The second button, emergency stop button, is located just where you enter/exit the MRI equipment room. This button kills the power to the MRI equipment in the room via a shunt trip breaker. The momentary push button has a raised collar to prevent someone from accidentally pushing the button.

In both cases big lettered signage is placed above each button.

 

[mannyb]

Did a CT room once, IIRC they wanted basically a E-stop style button that operated a shunt trip breaker in the main supply to the X-ray generator. I think we put one near the operator's station and one next to the entry door to the room. I don't know what any codes would require especially non NEC codes, but I think the equipment reps basically designed that and made the specifications for that install, I just put in what they asked for.

I would guess the "E-stop" for MRI would be somewhat similar. I don't think an operator would normally be in the room when MRI is active, so a station in the room may or may not be required, but I would think a station near the operator would be required.

From what I have heard about MRI is they calibrate the machine to the room, only thing that changes is the presence of the patient to be examined. Nobody enters room once a session is started or while in progress nor do they change any contents of the room or it can throw things off.

If there is an emergency and MRI needs stopped, I think it must be stopped before anybody enters the room. If so I could even see a door switch that disables the unit if the door is opened

The MRI equipment is similar to your experience. I will be askin for a little more help as the project progresses. Thanks guys.

 

[hbiss]

If there is an emergency and MRI needs stopped, I think it must be stopped before anybody enters the room. If so I could even see a door switch that disables the unit if the door is opened

I don't see that. All it would do is screw up the scan and at that point what's the difference. There should be no danger to those who enter the room as long as they adhere to the requirements for working in the magnet room- like not carrying anything magnetic. The EM button for the magnet is usually located in the room. Each facility has procedures for when that button is pressed, like evacuate the entire area immediately and leave the doors open.

-Hal

 

[Jamesco]

I don't see that. All it would do is screw up the scan and at that point what's the difference. There should be no danger to those who enter the room as long as they adhere to the requirements for working in the magnet room- like not carrying anything magnetic. The EM button for the magnet is usually located in the room. Each facility has procedures for when that button is pressed, like evacuate the entire area immediately and leave the doors open.

-Hal

Agree.

There better be a heck of a good reason for someone to push the button. Like a fire in the room for example. I can't think of any other reason. Can you?

 

[hbiss]

The MRI equipment is similar to your experience. I will be askin for a little more help as the project progresses.

We're here to help as much as we can. But our expertise is very limited when it comes to this, especially with technology that changes so rapidly. What someone may have done a few years ago with one manufacturer may not be applicable today.

I would recommend that you work closely and present your questions to the architect, engineers and techs that are in charge of the project. They would be the ones with the answers.

-Hal

 

[hbiss]

Agree.

There better be a heck of a good reason for someone to push the button. Like a fire in the room for example. I can't think of any other reason. Can you?

The most well known incident was when an employee who was not trained in proper magnet room protocol brought a steel oxygen cylinder and cart into the room and proceeded to connect it to the patient. The cylinder got pulled into the magnet pinning the (I think) patient. There was no way that the cylinder could be even moved. I think the patient ultimately died from the trauma. Nobody thought to hit the EM magnet quench button until some time later when it was too late for the patient. Usually when a situation like this occurs you are going to get everybody available to come and help out, so they may or may not know anything about proper procedures.

Just to show how powerful that magnet is, there is a You tube video of some guys at a facility that is about to be decommissioned. They decided to play with it. They built a ramp in front of the magnet out of 2x4s. They then put ordinary office objects on the ramp and brought them closer and closer to the bore with a winch. One item was a little office chair. They had a tension gauge tied to it so they could see how much force was being exerted. When it got right at the opening of the bore the pull was over 5000 pounds.

-Hal

 

[cdslotz]

We are building an MRI facility. They will test the MRI but will have an emergency run down button for emergency. Does anyone have any experience with this type of install. Is this basically a shunt trip to breaker. we are at beginning stages of construction but I would like to know a little before I would start. if you have any pics or information please share.

Usually there are detailed electrical drawings of the MRI machine drawn specifically for the room it is going into. You need that drawing.
These details will not be on the electrical or architectural drawings.
The manufacturer like Seimens, GE, etc have these drawings.

 

[Jamesco]

The most well known incident was when an employee who was not trained in proper magnet room protocol brought a steel oxygen cylinder and cart into the room and proceeded to connect it to the patient. The cylinder got pulled into the magnet pinning the (I think) patient. There was no way that the cylinder could be even moved. I think the patient ultimately died from the trauma. Nobody thought to hit the EM magnet quench button until some time later when it was too late for the patient. Usually when a situation like this occurs you are going to get everybody available to come and help out, so they may or may not know anything about proper procedures.
-Hal

That is why the magnet quench button is located inside the room.


Wow! Yeah, that would be a good reason to hit the button.

Where were the trained MRI Room operators? They should have stopped the employee from ever entering the room.

Did the operator/s even know what the button was for? It should have been clearly labeled.



Jim