Computation of hyperthermia-SAR distributions in 3-D

A formulation for the solution of the general Maxwell's equations to predict the electromagnetic power deposition (as the specific absorption rate, SAR) in a three-dimensional model of a human body irradiated by an annular array applicator used for hyperthermia is investigated. Methods for generating the grid as well as displaying the three-dimensional solutions are presented. A least-squares finite-element approach to the problem is developed. Difficulties which arise as a result of the finite-element trial functions are identified that make it difficult to impose the divergence and curl equations together. The boundary-element formulation, which relies on the free-space analytical solution, is shown to overcome this difficulty and is demonstrated in two dimensions. These methods form the basis of a treatment planning system under development which will have the capability of generating the finite-element grid model of the body from computerized tomography scans solving for the fields, and displaying the absorbed power distributions.<
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