Oxygen Monitoring for MRI Rooms

[mechanicaldude]

I am designing an MRI room and the hospital is requesting oxygen monitoring for the exam room in case of helium purging. Has anybody done this before. Will an emergency Purge exhaust fan also be required? What kind of device is used for this and can it be installed in the actual MRI room?

 

[ScottyUK]

Crowcon and GMI are three major manufacturers of gas detection and atmospheric monitoring.

http://www.crowcon.com/fixedgasdetectors.htm

http://www.gmiuk.com/fixed.html

http://www.draeger.com/ST/internet/US/en/Industries/GDS/General/Toxic/Industrial/ggi_industrial.jsp

I guess the question relating to installation in the MRI room relates to the external magnetic field? I absolutely do not know what is required for an MRI application, but in my industry we try very hard to keep all electronics well away from the stator of our generators because of the high external flux, especially around the stator ends. The problems are similar, but in your case it is a life safety application. I would expect that the best solution would be mount the sensor at the MRI room and house the electronics away from the MRI unit or possibly use an aspirated system which samples air at a remote location by pumping air through a sensing tube. In a safety application I strongly recommend getting a manufacturer involved early and asking for their assistance.


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Sometimes I only open my mouth to swap feet...

 

[GMcD]

Every MRI I've done in the last 10 years has a separately ducted helium relief/purge connection off the MRI that is ducted to outdoors. Modern MRI machines, as far as the ones I've dealt with (Siemens, GE)have zero chance of leaking helium into the MRI room based on their construction. Is this an old, relocated MRI?

 

[mechanicaldude]

This is a new MRI and there is a Cryogen vent for the magnet, but the Philips also still recommends monitoring the O2 levels. Thanks for your reply.

 

[mribuilder]

I have extensive knowledge in all aspects of site planning for MRI, CT, Cath, Linac, etc. As for O2 Monitoring. #1 is that there is only one (1) approved unit, (must have a UL listing) and that's the Tox-Guard II. The unit must be placed in the Control Room and the sample tube run through an RF wave guide. I can send you digital pics if you want to see how to install. Note that this is a requirement of the OEM, NOT OSHA nor any published MRI Standards assuming this is a cryostat magnet no less than 4 years old.

 

[mribuilder]

On another note if you are designing the HVAC as well there are other things to take into consideration:
1 - Temp & Humid monitoring, (RA duct).
2 - Access points on BOTH sides of RF wave guides for future cleaning.
3 - All alum ductwork in Scan Room and critical placement of SA & RA depending on the actual MRI system.
4 - If it's a GE or new Hitachi high field there are requirements for exhaust to be interlocked with that O2 monitor.
5 - Chiller system by-pass and remote monitoring panels.

 

[atlas06]

A good design guide is the VA guidelines, you will find all sorts of design guidelines, design alerts, details in ACAD, etc.
Go to "Technical Information library" in the site.

For your code compliance, you need to check AIA/HHS Hospital Design Guidelines.

http://www.va.gov/facmgt/

Best

Atlas

 

[JLSeagull]

I am not familiar with the Tox-Guard II and do not find it on the web. Oxygen deficiency monitoring is a common requirement for buildings with compresses gas tubing or cylinders, etc. This applies to any gas that could displace the oxygen. Excess oxygen is also monitored if the gas is O2.

Most of the gas detector manufacturers such as Det-Tronics have such monitors. Servomex and others sell specific oxygen analyzers that are well suited. Most gas detector manufacturers are rated to NFPA standards. Other third party agencies such as FM and sometimes CSA-USA are acceptable. This could be up to the insurance provider for the facilities.