This report originally appeared in the January 2009 issue of DOTmed Business News

Don't think of it as an installation of a magnet into a room. Instead, think about an entire building being designed and constructed around the eventual magnet site.

That's what has been going on at Johns Hopkins University Department of Radiology since they broke ground in September 2007 for the Kennedy Krieger Institute Clinical Research Building on North Broadway in Baltimore. The building houses a magnet to be used in functional brain imaging at the F.M. Kirby Research Center.
The MRI, a 35-ton Philips Achieva 7T that can scan the whole body, was put in place in November 2008. It's scheduled to be brought up to field this month and become operational in March 2009.

Before the MRI arrived, a tremendous construction project was completed. A steel-shielded room was built in the spring of 2008 to accommodate the MRI. The room was designed to contain the 140,000 pounds of magnetic force exerted by the magnet. The 440-ton, six-sided room has walls 16 inches wide at its thickest point, and made of 10,000-pound annealed steel plates, each two inches thick. Special steel is used for the job - an alloy with high magnetic permeability.

"The soft steel helps the current of the magnetic field flow in the steel. What you are doing is redirecting the current in the magnetic field; that is how you contain it," explained Richard Lee, President, Lee & Associates, Shreveport, LA, the shielding contractor on the project.

The MRI was rigged and set to fit exactly in the center of the steel room, which sits on special air springs since the magnet must be isolated from the vibration of nearby Metro trains and street traffic.

Radiofrequency shielding was also added to the MRI suite. This is because the room must not only keep magnetic forces in, it must also keep out any RF interference from radio stations, wireless networks, cell phones, and other transmissions and devices.

The Baltimore magnet will be one of more than a dozen 7T ultra-high-field whole body MRI installations in the U.S. There's also an 8T magnet at Ohio State University and a 9.4T magnet at the University of Illinois at Chicago.

For an exclusive briefing on the use of the MRI from the research
scientists at Kennedy Krieger's F.M. Kirby Research Center, go to
https://www.dotmed.com/news/story/6720/

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