Analysis of temperature distributions generated by square array applicatorcomposed of coaxial-slot antennas for hyperthermia

Hyperthermia is a cancer treatment that seeks to destroy cancer cells by he ating. The authors have carried out analysis of coaxial-slot antennas as a hyperthermia heating device that uses microwaves. For characteristic evalua tions of the hyperthermia. heating device, the SAR (Specific Absorption Rat e) as a value proportional to the square of the electric field near the ant enna has been used widely. However, since hyperthermia seeks to heat cancer cells, it is desirable to know the temperature distributions inside actual biological bodies. In this paper, by means of the FDTD method, the SAR dis tribution around a coaxial-slot antenna in a biological body is computed. B y solving the biological thermal transport equation with the SAR distributi on as the heating source, the temperature distributions inside the biologic al body are computed. It is found that a hot spot can be generated due to t he low thermal conductivity of the fat layer even if the coaxial-slot anten na used is an insertion-type antenna. As an application of this simulation, the temperature distributions are studied when the feed power of the anten na is on-off controlled. It is found that the uniformity of the temperature distribution inside the body is improved and the hot spot in the fat layer can be reduced. (C) 2001 Scripta Technica, Electron Comm Jpn Pt 2.