it is important to define the distance or volume over which the local induced electric field must be averaged. As a practical compromise, satisfying requirements for a sound biological basis and computational constraints, ICNIRP recommends determining the induced electric field as a vector average of the electric field in a small contiguous tissue volume of 2 2 2 mm 3. For a specific tissue, the 99th percentile value of the electric field is the relevant value to be compared with the basic restriction.