Page 264 - Biomedical Engineering and Design Handbook Volume 2, Applications

IEC 60601-2-33 second controlled mode (needs IRB approval) 4 W/kg Whole-body ave SAR > 3.2 W/kg 10 W/kg in head 20 W/kg in extremities first controlled mode first controlled mode first controlled mode

> 4 T with 6 min ave. Ave. head SAR > with 6 min ave. Local SAR > or trunk, > with 6 min ave. Partial SAR > SAR > > dB/dt
B 0

4 W/kg 3.2 W/kg 20 W/kg

IEC 60601-2-33 controlled mode (operator takes deliberate action to enter) 4 T Whole-body ave. SAR 10 W/kg in head or trunk, in extremities with 6 min ave. 10–6 W/kg (exposed mass/total mass limits between 4 and 10 W/kg): SAR over any 10 s period may be up to 3 times appropriate long-term SAR level 100% of peripheral

2 T < B 0 with 6 min ave. Ave. head SAR with 6 min ave. Local SAR Partial SAR 6 min ave. dB/dt nerve mean

2 W/kg 3.2 W/kg 20 W/kg in extremities

IEC 60601-2-33 normal mode 10 W/kg in head 10–8 W/kg (exposed mass/total mass limits between 2 and 10 W/kg): SAR over any 10 s period may be up to 3 times appropriate 80% of peripheral

2.0 T Whole-body ave. SAR with 6 min ave. Ave. head SAR with 6 min ave. Local SAR or trunk, with 6 min ave. 6 min ave. long-term SAR level nerve mean

SAR
B 0 dB/dt

4 W/kg

FDA significant risk criteria (http://www. fda.gov/cdrh/ode/ magdev.html) Whole-body ave. SAR ≥ 3 W/kg 8 W/kg in any gram (head or torso) Sufficient for severe discomfort

MR Safety Standards 4 T > B 0 with 15 min ave. Ave. head SAR > with 10 min ave. Local SAR > N/A N/A

TABLE 8.1 Safety parameter B 0 WB SAR Head SAR Local SAR Partial body SAR Short-term SAR dB/dt

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