Industriestrasse West 14
4614 Haegendorf CH
+41 62 209 40 20

Radio Frequency Shielding

MRI equipment generates strong RF interference, which can disturb other
electronic equipment in the hospital or affect television and radio reception in
the neighbourhood. Conversely, external RF signals may be picked up by the MRI
system’s RF coils and adversely influence the accuracy of the imaging data. MRI
scan rooms therefore have to be efficiently shielded to prevent radiation
leaving or entering.

The IMEDCO 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 IMEDCO personnel.

The following excellent attenuation figures are
typical values which vary according to the MRI equipment in use:

 Field: Frequency:   Attenuation:
 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