“That’s affecting the shielding industry more so than it ever has before,” says Krachon.

The design concept as to how the shield is assembled and installed can also affect RF shield effectiveness and reliability. Long term issues can arise based on how the seams of the panels or sheets are joined and how outside environmental issues such as shield vibration, moisture and humidity, and the structural stability of mounting frames and fastening methods impact these seams and joints. Sites with irregular shield floor plans and site space constraints put even more emphasis on design durability.


Ken Wilkens, a senior R&D engineer at the Vanderbilt University Institute of Imaging Science, is involved in the renovation of MR rooms at the institute and says it doesn’t hurt to add a few extra features.

“Another item, especially in the research environment, is to add extra blank penetration panels that can be filled out later,” he told HCB News. “It is much easier to add a panel when the room is being built then to add one later. If any functional imaging is planned, and space permitting, add a large waveguide along the magnet bore center behind the magnet. This will allow for a conventional projector, with appropriate lens, to be used instead of a specialty MR compatible projector. While the shield is being installed, there will be no scanning at all. In fact, the magnet will probably be ramped down during the process.”

In some cases, a shield might cost in excess of $200,000, but price can be a tell-tale marker in distinguishing a shield that will last three years from one that is still effective after ten.

According to Peter Haines, a project specialist for Banner Health, a non-profit health system, the price for each shield installation must be taken into consideration with the costs of other necessary items, such as LED lights and metal detectors.

Typically, he says, they can range from $65,000 to $100,000.

The price, conditions, design and location of a shield all should be considered before installations start and they are merely the first of many factors that determine how long a shield will last.

You have a shield … now what?

For some providers, the first shielding mistake is completing a successful installation and then believing they no longer have to think about it anymore.

“The majority of owners, hospitals and clinicians really seem to pay little attention to the shield maintenance packages,” said Krachon. “It’s not uncommon for users to be excited once a shield is installed and then not touch the thing again for their entire lifetime until they begin to experience imaging problems. They all have maintenance arrangements for the MRI but few have one for the shield which could have the greatest single impact on MRI performance."

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