"Check references and do not rely on the architect to select your shielding company because they don't research companies," notes Paul Yastrab, Physicians Imaging Solutions, Akron, OH. "Always insist on two shield tests: one upon completion of the room and one after the magnet is installed."

"Get the references and test the room by an impartial tester," confirms Marshall Shannon, Director, Image Technology Consulting, LLC, DeSoto, Texas. Never, I repeat never take the word of the installer that the room is tight."


"I would advise getting the shielding contractor involved in the early stage in any type of discussion. A good one will work with your architect for free to design the system," Holder adds. "Too often inexperienced architects don't understand the nuances of shielding and may give you four inches to build a shielded wall and it doesn't work.
You've got to get it down on paper from day one."

Devil in the Details

Any large metal objects in motion near your suite (trucks, subway cars, elevators) can cause a problem for your MRI in terms of magnetic forces, vibration, and/or electrical output, all concerns for the shielding design.

In addition to site specifications, trends in MRI design also affect how new equipment is shielded. The new machines are lighter, which helps installers, but also leaves the suite more susceptible to vibration to be mitigated by the shield. New, large bore equipment may also impact shielding specifications.

Older equipment may have significant magnetic shielding already in place since MRIs of yesteryear weren't self-shielded magnetically like today's machines. However, with the increased field strength in favor today, even heavy, older shielding may not be enough if it's not welded. You will likely need to replace the shielding in the room when you upgrade to a new MRI system.

Anything that penetrates the shield requires additional attention: special RF filtering for wiring, wave guide protection on pipes, and specialized honeycomb material for air vents. Windows and doors are shielded with copper screening. The MRI suite also requires shielding a pipe for helium exhaust along with a specially secured door and window.

Specialized MRI applications require similar meticulousness such as shielding interoperative MRI systems that must work nearby surgical lighting, gases, monitors, and other equipment. Mobile and temporary MRI facilities must also be protected and aluminum is often used for RF in those settings.

Finally, it's important to remember that safety considerations for the equipment, as with patients, extend long after the room is shielded.

More Industry Reports