Theoretical electric field distributions produced by three types of regional hyperthermia devices in a three-dimensional homogeneous model of man

A boundary-element formulation of the Maxwell equations is used to solve for the electric field in a three-dimensional homogeneous model of man. The boundary element grid is constructed from cross-sectional slices of the body in such a way that the contour of the body surface is preserved, but the interior heterogeneity is not taken into account. By using the method in conjunction with a homogeneous three-dimensional model, only the body surface and the source are discretized; hence, the computational resolution required for detailed three-dimensional modeling is reached within the constraints of moderate computing power (MicroVax II). Electromagnetic source arrangements simulating three types of regional noninvasive hyperthermia systems are examined, namely magnetic induction devices, annular array applications, and capacitive heating systems. Results indicate that the longitudinal extent of the electric fields produced by the annular array and capacitive heating models can be significant, suggesting that three-dimensional simulation of these types of devices may be required to fully understand their capabilities.