Table 4

Exposure metrics by MR magnet strength: instantaneous peak exposure levels, average exposure levels weighted for the duration of the shift (shift-weighted average; SWA) and average exposure levels weighted for the time exposed to SMF (exposure-weighted average; XWA)

B (mT)dB/dt (mT/s)
NobsNsubAMGMGSDBWGSDWWRangeAMGMGSDBWGSDWWRange
Magnet strength
Instantaneous Peak exposure
 1.5 T138945944172.381.7220–289110485393.012.059–12 455
 3.0 T65126112491.131.061069–1588156014271.231.11961–1903
 1.5 and 3.0T33128312741.13–*1069–1412184817311.421263–2833
Total147†102‡6354472.232.4120–289110825742.812.789–12 455
SWA
 1.5 T1389418161.291.535–6416141.321.439–105
 3.0 T6524232.151.0015–3818171.351.0410–23
 1.5 and 3.0 T3322191.6712–4027261.3619–39
Total14710219161.391.645–6416141.331.589–105
XWA
 1.5 T1389428261.201.4011–6419161.361.439–124
 3.0 T6550471.501.0027–8927251.531.0516–46
 1.5 and 3.0 T3337351.4222–5031301.2225–40
Total14710229271.341.5711–8919171.371.609–124
  • *No within-participant repeats were available for 1.5 and 3.0 T MR systems.

  • †No information on magnet strength was reported in two MR procedures.

  • ‡Higher number of participants (compared to table 3) because some of the participants worked on different MR systems from day-to-day.

  • AM, arithmetic mean; GM, geometric mean; GSDBW, between-participant geometric SD; GSDWW, within-participant geometric SD; Nobs, number of observations; Nsub, number of individual participants; SMF, static magnetic fields.