may vary significantly depending on electrical design, orientation of the device relative to the
magnetic field, and the degree of interference considered unacceptable.
Site plans must include consideration for magnetic field interaction with all customer equipment.
Use the table for reference only. The gauss limits in the table are approximate for that type of
equipment. Refer to OEM manuals for the equipment at your site to determine the actual Gauss
limits.
Table 2-6: Magnetic Proximity Limits
Gauss (mT) Limit
Equipment
0.5 gauss (0.05mT)
Nuclear camera
1 gauss (0.1mT)
Positron Emission Tomography scanner
Video display (tube)
Linear Accelerator
CT scanner
Cyclotrons
Ultrasound
Accurate measuring scale
Lithotriptor
Image intensifiers
Electron microscope
Bone Densitometers
3 gauss (0.3mT)
Power transformers
Main electrical distribution transformers
5 gauss (0.5mT)
Cardiac pacemakers
Biostimulation devices
Neurostimulators
10 gauss (1mT)
Magnetic computer media
Telephone switching stations
Hard copy imagers
Water cooling equipment
Line printers
HVAC equipment
Video Cassette Recorder (VCR)
Major mechanical equipment room
Film processor
Credit cards, watches, and clocks
X-ray tubes
Large steel equipment, including:
Emergency generators
Air conditioning equipment
Commercial laundry equipment
Fuel storage tanks
Food preparation area
Motors greater than 5 horsepower
50 gauss (5mT)
Metal detector for screening
Telephones
LCD panels
No Limit
Digital Detectors
6.5 Magnet Shield
NOTICE
If a site has an existing magnetic shield and an upgrade to the LCC RD magnet
is being performed, the existing shield must be evaluated by the GE Healthcare
MR Siting And Shielding Group.
Magnetic shielding is used to reduce the fringe field around the magnet. Refer to
for
the fringe field plots for the Magnet.
SIGNA Voyager Pre-Installation
Direction 5680008–1EN, Revision 2
38
6 MR Suite Magnetic Field Specifications