Numerical evaluation of radio frequency power deposition in human models during MRI

Concerns have been expressed about safety of MRI examination of two groups of people, namely pregnant mothers and cardiac pacemaker bearers. The main uncertainty relates to excessive heating by pulsed radio frequency (RF) fields. To address these issues, numerical evaluations of the power deposition are performed for a 27-week old fetus in a simplified model of the mother, and a realistic model of a human torso with an in situ pacemaker including its leads. The evaluations are supplemented with organ dosimetry for a realistic model of the human torso. An ideal non-resonant and two resonant birdcage coils operating at 64 MHz (corresponding to 1.5 T MRI) are evaluated. All simulations are performed with the finite difference time domain (FDTD) method.