The Vanguard System RF enclosure is basically a Faraday cage constructed of panels of high-quality copper foil wrapped round wooden frames, which are clamped together such as to ensure the integrity of the shielding throughout the life of the enclosure. Electrical cables, medical gas pipes and other supplies are routed out of sight in the wall cavities. This method of construction gives the architect full freedom of design and permits subsequent replacement or modification of the MRI equipment. If necessary, with the exception of the floor, the enclosure can be dismantled and erected at another location. All fittings are of non-magnetic materials. Doors, windows and penetrations for services are also shielded or fitted with filters to prevent leakage. RF enclosures are dielectrically insulated from the rest of the building. They are delivered to site in prefabricated modules and assembled by trained Vanguard System personnel.
The following excellent attenuation figures are typical values which vary according to the MRI equipment in use:
|Magnetic field||15 MHz||100 dB|
|Electric field||10 MHz||100 dB|
|30 MHz||100 dB|
|Plane Wave||30 MHz||100 dB|
|100 MHz||100 dB|
|200 MHz||100 dB|