Flat left-handed metamaterial (LHM) lens can generate appropriate focusing spot in biological tissue as required in microwave tumor hyperthermia treatment. By using single flat LHM lens to concentrate microwave in a mass of tissue covered by water bolus, microwave hyperthermia scheme is proposed for superficial tumor hyperthermia. The power distribution in tissue is simulated by finite-difference time-domain method, and the thermal pattern is calculated by solving the bio-heat transfer equation. It is demonstrated that, by using a flat LHM lens of thickness of 4 cm to concentrate microwave of 2.45 GHz, a temperature above 42oC can be achieved and maintained in one hour in a tissue region of about 1.0 cm in width and 1.2 cm in depth in tissue with the source amplitude of 43.40 V/cm, which is suitable for superficial tumor hyperthermia. By adjusting the position of microwave source, the heating zone in tissue can be adjusted in both the lateral and depth direction in tissue. The effects of fat layer and water bolus on the performance of hyperthermia are investigated as well.
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