From the October 2013 issue of HealthCare Business News magazine
By Michael Profeta
Radio Frequency Shielding is one of the most important factors
to consider when planning an MRI suite because it has a direct impact on image quality. The RF shield is built to keep electrical, or RF noise found in our everyday environment from getting onto the images. Like the foundation of a building, everything else depends on the structural soundness and long term reliability of the shield.
The shielding consists of a metal layer installed in the structure of the MRI exam room, including walls, floor, and ceiling. All the seams need to be continuous and tight. Even a short slice will compromise the shield performance. Anything that enters or exits the MRI exam room such as air conditioning, electrical wires, and plumbing lines need to pass through special filters or waveguides.
In the early design stages:
Numed, a well established company in business since 1975 provides a wide range of service options including time & material service, PM only contracts, full service contracts, labor only contracts & system relocation. Call 800 96 Numed for more info.
Interview architects and construction companies to be certain they have prior experience in the design and construction of MRI suites. There are many special requirements and guidelines that vary between manufacturers. Having experienced professionals familiar with the brand MRI machine you are considering is a huge plus.
When considering the RF shielding vendor there are several factors to focus on.
Materials, construction styles, and long term reliability should be understood. Get educated on how each vendor builds the shielding. Understand why some materials and methods are better than others. There are reasons for variations in quotes beyond the bottom line. It is important to understand what RF vendors offer in regards to cost, products, quality, warranty, technical support, and on site construction crews. Remember that often times the shielding vendor is more familiar with the MRI requirements than the architect and construction companies. So ask questions and find a shielding vendor that not only has in house expertise, but who also sends expert installation technicians.
After the dust settles
RF shield testing is completed directly after the magnet is installed. Make sure all major construction is completed before the final test. Typical warranties are five years on the shielding and one year on the MRI door and filters. Schedule a follow-up test before the door warranty is up. It may cost you a little extra, but any repairs outside normal wear and tear are covered.
RF shielding needs maintenance
RF shield compromises can cause very subtle to extreme changes in image quality. Elevated levels of background noise or coherent line artifacts can run through the images. Often times the artifacts are intermittent and dismissed as random glitches. A properly maintained MRI shielding system eliminates these artifacts insuring the highest quality image all the times.