MAGNETIC PROXIMITY LIMITS
STEEL MASS LIMITS TO MAGNET ISOCENTER (3x3 m [10x10 ft] AREA UNDER MAGNET)
Limits Of Steel Mass
Distance From Magnet Isocenter
Distance Below Top Surface Of Floor
mm
in
mm
in
0
0
0 - 1143
0-45
0 - 76
0-3
9.8
2
1143 - 1194
45-47
76 - 127
3-5
14.7
3
1194 - 1321
47-52
127 - 254
5-10
39.2
8
1321 - 1397
52-55
254 - 330
10-13
98.0
20
1397+
55+
330+
13+
The actual field strength can be affected by Magnetic shielding, Earth's magnetic field, other magnetic fields and
stationary or moving metal. This information must be used to evaluate potential site interaction of GE Healthcare
equipment with other non-GE Healthcare equipment. Magnetic shielding can be installed to prevent interaction
between the magnet and nearby sensitive devices. The GE Healthcare Project Manager of Installation (PMI) can work
with the customer to coordinate the magnetic shielding site evaluation. The customer is responsible for installation
of all magnetic shielding.
The customer must provide detail defining ferrous material below the magnet to the Project Manager so the GE
Healthcare MR Siting and Shielding team can review for compliance.
Gauss (mT) Limit
Equipment
0.5 gauss (0.05mT)
Nuclear camera
1 gauss (0.1mT)
Positron Emission Tomography scanner, Linear Accelerator, Cyclotrons, Accurate measuring scale, Image intensifiers,
Bone Densitometers, Video display (tube), CT scanner, Ultrasound, Lithotriptor, Electron microscope, Digital X-Ray
3 gauss (0.3mT)
Power transformers, Main electrical distribution transformers
5 gauss (0.5mT)
Cardiac pacemakers, Neurostimulators, Biostimulation devices
10 gauss (1mT)
Magnetic computer media, Line printers, Film processor, X-ray tubes, Emergency generators, Commercial laundry
equipment, Food preparation area, Water cooling equipment, HVAC equipment, Major mechanical equipment room,
Credit cards, watches, and clocks, Air conditioning equipment, Fuel storage tanks, Motors greater than 5 horsepower
50 gauss (5mT)
Metal detector for screening, LCD panels, Telephones
No Limit
Digital Detectors
SOUND PRESSURE SPECTRAL DISTRIBUTION
20
25
31.5
40
50
63
80
100
125
160
200
250
315
400
500
630
800
1000
1250
1600
2000
2500
3150
4000
5000
6300
8000
10000
12500
16000
SPL (dBA) - normalized
Frequency (1/3 Octave)
1/3 Band Relative SPL
20000
16
12.5
0
5
10
15
20
25
30
Acoustic and vibroacoustic information is provided for site planning and architectural design activities. It is the
customer's responsibility to hire a qualified acoustic engineer for solutions to further attenuate this transmitted
noise and vibration, if required.
The actual room noise level may vary based on room design, optional equipment, and usage:
ACOUSTICS SPECIFICATIONS
Average sound pressure level
Frequency
Control room
80dBA
20 Hz to 20kHz
Equipment room
80dBA
20 Hz to 20kHz
Magnet room
127 dBA
20 Hz to 20kHz
ISOGAUSS PLOTS
* The isogauss contour plots depicted on this drawing represent magnetic fringe fields resulting from the normal
operation of the magnet provided with the MR system. The actual magnetic field intensity at any point in the
vicinity of the magnet when installed may vary from the contour plots due to factors such as the concentrating
effects of nearby ferrous objects ambient magnetic fields, including the earth's magnetic field. Therefore, the
contours shown are only approximations of actual field intensities found at a corresponding distance from the
magnet's isocenter.
Date
Rev
/24
EN-MRI-TYP-SIGNA_EXPLORER-WEB.DWG
A
03/Aug/2018
SIGNA EXPLORER /SIGNA CREATOR
Typical
A4 - Acoustic - Proximity Limits
06
