MRI Safety Guidelines (1982)

Static Magnetic Field ( Bo )
Maximum clinical imager magnetic field2.0 T
Maximum inadvertant exposure 0.0005 T

Rate of Change of Magnetic Field (dB/dt)
System < 6 T/s
Axial Gradients > 120 s < 20 T/s
12 s < < 10 s < 2400/(s) T/s
< 12 s < 200 T/s
Transverse Gradients < 3x above
= risetime of gradient

RF Power Deposition
Temperature (37o C normal) Change < 1 o C local
Maximum Head < 38 o C
Maximum Trunk < 39 o C
Maximum Extremities < 40 o C
Specific Absorption Rate (SAR) Whole Body < 0.4 W/kg
Any 1 gram of tissue < 8.0 W/kg
Head (averaged) < 3.2 W/kg

Acoustic Noise Level
LPeak 200 Pascals
Leq. averaged over 1 Hr 105 dBA