Eugenia Cabot1, Tom Lloyd2,
Andreas Christ1, Gregg Stenzel2, Wolfgang Kainz3,
Steve Wedan2, Niels Kuster1,4
1IT'IS Foundation, Zurich,
Switzerland; 2Imricor Medical Systems, United States; 3FDA,
Rockville, United States; 4Swiss Federal Institute of Technology
(ETHZ), Zurich, Switzerland
A methodology for RF safety assessment of implants based on a 4 tier approach was evaluated for 1.5T scanners using a generic model of a deep brain stimulator. A combination of numerical (FDTD simulations) and experimental techniques was used. The different tiers were followed to assess the energy deposition and the temperature increase at the tip of the implant in a human head model. Each consecutive tier yields a less conservative result, but requires greater computational effort to demonstrate safety. Results showed that Tier 4 is technically feasible but too computationally demanding. An enhanced Tier 3 is then suggested.