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Table 3 Geometrical data and power losses for example resonators

From: Finite volume analysis of temperature effects induced by active MRI implants with cylindrical symmetry: 1. Properly working devices

Resonator No   1 2 3
Radius of ring resonator Rimp [mm] 18 5.55 1.5
Length of ring resonator Limp [mm] 50 9.9 14
Dimension of ring wire axial xwire [mm] 0.25 0.15 0.10
Dimension of ring wire radial rwire [mm] 0.25 0.15 0.10
Number of rings (turns) nr   2 6 12
Volume of implant Vimp [cm3] 50 1 0.1
Quality factor Q   5 12.5 80
Total power loss of resonator Ploss [mW] 1000 50 32
SAR inside resonator (Eq. (3b)) SARinternal [W/kg] 1.8 1.7 5.1
Power loss of resonator due to SAR PSAR [mW] 0.09 0.0016 0.0005
  1. Power losses PSAR and Ploss are calculated for the MR sequence of Table 2. SARinternal is evaluated with Eq. (3b). PSAR can be calculated using SARinternal and the mass inside the inductor (mimp = ρtissue Vimp), whereas Ploss is calculated with the appropriate constants according to Eq. (7). Ploss for resonator no 2 was verified experimentally with temperature increase measurements after placing the resonator inside a phantom with known heat capacity.