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. 2022 Feb 26;22(1):7–25. doi: 10.2463/mrms.rev.2021-0047

Table 2.

Safety SAR limits in the IEC standard

Operating mode Whole-body SAR (W/kg) Partial-body SARa (W/kg) Head SAR (W/kg) Local SAR (W/kg)b
Headc Trunk Extremities
Normal 2 2–10 3.2 10 10 20
First-level controlled 4 4–10 3.2 20 20 40
Second-level controlled > 4 > (4–10) > 3.2 > 20 > 20 > 40

Averaged SARs over 6-min RF exposure. anormal operating mode: Partial-body SAR = 10 W/kg − (8 W/kg × exposed PATIENT mass/PATIENT mass) and first (second)-level-controlled operating mode: Partial-body SAR ≧ 10 W/kg − (6 W/kg × exposed PATIENT mass/PATIENT mass). bAveraged over mass of 10 g. cIn cases where the orbit is in the field of a small LOCAL RF TRANSMIT COIL, care should be taken to ensure that the temperature rise is limited to 1°C. SAR, specific absorption rate.