Heating near implanted medical devices by the MRI RF-magnetic field

The temperature rise in the vicinity of a medical implant due to the RF field in Magnetic Resonance Imaging (MRI) was evaluated. For the calculations, the implant was taken to be a conducting cylinder resembling the geometry of a commercial infusion pump. Measurements of temperature rise were made with the pump in a phantom in a clinical imager. The RF protocol was 20-minutes long and produced a specific absorption rate (SAR) of 0.95 W/kg in the 34-kg phantom. In the measurements, the maximal temperature rise near the implant (0.66/spl deg/C) was about 3 times the control rise (0.23/spl deg/C) with no implant. The calculations are consistent with experiment.