Adaptive Nulling in the HyperthermiaTreatment ofCancer

.. We have investigated the use of adaptive array antenna techniques to maximize the applied electric field at a tumor site in a target body while simultaneously minimizing or reducing the field at the locations of undesired high-temperature regions, or hot spots. Computer simulations have shown that adaptive nulling can prevent undesired hot spots from occurring during the heating of a deep-seated tumor! The simulation results have been supported by experimental measurements with a c<,munercial hyperthermia phased-array antenna system that was modified to!implement adaptive-nulling and adaptivefocusing algorithms. The experimen~wereconducted at the State University of New York (SUNY) Health Science G~nter in Syracuse, N.Y. Two types of phantom targets-a saline-filled polyethylene bottle and a beef sample-were used in the expetiments. Results indicate that adaptive nulling can be used to reduce the electric field at one or more target positions while simultaneously maintaining a focus at a deep-seated location within the target.