"In some cases now, with the existing rooms, manufacturers have gone back and inspected the venting of the cryogen gas finding deficiencies in existing conditions that they have customers remedy," Profeta says. "We have been contacted by a lot of sites where they have to replace the vent pipe systems because they were improperly installed. Where the door opens inward, they want us to also add a pressure relief vent in the wall or ceiling. This is all relatively new and I agree with this emphasis on safety."

This safety feature can literally be a lifesaver in the event of a magnet quench coupled with faulty or malfunctioning vent pipe system. A quench causes the magnet to quickly heat up and leads to a complete discharge of helium. At best, it can be a costly problem, causing a loss of liquid helium and significant time and money to bring the magnet back to field. At worst, it can release a cloud of cold helium gas that can prove deadly to anyone unable to quickly leave the room.


Common Problems

When properly shielded, an RF room can almost be comparable to an airtight room, but every time you open and close the door-almost like a compression with a vacuum-what happens is that staples and joints start to weaken and other problems develop.

Once the scanner is up and running you may see what is called artifact or noise on the screen across the image. A good MRI tech will be able to tell you what frequency those artifacts are at and can see the degradation of image quality over time.

"There are three basic types of problems that cause this," Turner explains. "The first is simple RF leakage, which is usually not a difficult thing to find. It may be inconvenient in that you may have to tear down drywall to get to the shield to fix it but all in all, this is the least problematic."

This often occurs because outside contractors come and violate the wall by adding wires, phone lines or lights by drilling through the shield. When this happens, the scans will be as bad as if someone left the door open.

"We just checked one in Bakersfield where they changed ownership and they put in an alarm system and the guy didn't realize what an RF room really was," Vojak says. "They drilled a hole in it causing leaks so we fixed that. While we were there we noticed the door was out of alignment and the finger stocks weren't meeting properly so we cleaned and realigned the door as well."

Another problem concerns the magnetic field. Turner explains you may have equipment up the hall or below the MRI suite that hasn't been functioning properly and it's because the MRI magnetic field is sticking out further than it should be.

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