A Fast and Accurate Device Model Validation Strategy Using Rotational Invariant Lead Trajectories

The ISO/TS 10974 standard indicates that as an electromagnetic model of active implantable medical device (AIMD) for prediction of power deposition in homogeneous media or tissue, the transfer function shall be validated using a set of tangential electric field exposures. However, the pathways suggested by ISO/TS 10974 are too sophisticated to practically achieve, and the correlation among those trajectories is significant. In this paper, a new strategy is proposed to overcome these shortcomings. Applying an algorithm based on Partial Swarm Optimization (PSO), the validation trajectories applicable for AIMDs with different length of stimulation lead in ASTM rectangular phantom are generated with high degree of orthogonality. Using the rotatable circular bench, there is no need to re-position the AIMD inside the phantom during the validation test. As the plate rotates, sufficiently different incident fields along lead trajectories can be achieved. The determination of pathways for AIMDs with different length are given, and compared with those suggested by ISO/TS 10974 in terms of correlation level. Two commercial AIMDs are used as the examples to demonstrate the feasibility of the proposed strategy. The new procedure reduces the uncertainty and experiment time. Also, the tangential components of incident electrical fields along different trajectories are orthogonal to each other, which makes transfer function validation test more efficient.