Table 2.

Data for calculation of the power density P_V of an active implant referring to Eq. 1 for an MRI sequence with an SAR of 4 W/kg (manufacturer declaration)

permeability of vacuum	μ0	[V s/(A m)]	12.6E-7
magnitude of magnetic excitation field	B1	[μT]	25
repetition time of MRI sequence	TR	[s]	2.23
duration of one excitation	τ	[ms]	0.80
number of identical excitations during TR	N		246
duty cycle cdc N τ/TR	cdc		0.09
pulse waveform modulation factor cpwm	cpwm		0.45
Larmor frequency = resonance frequency of LC circuit	ν0	[MHz]	63.8
ω0 = 2π ν0	ω0	rad/s	4.0 108
power loss density PV = P/(Q Vind) (Eq. 1)	PV	[mW/(cm3Q)]	4.0