Design of Noninvasive Hyperthermia System Using Transmit-Array Lens Antenna Configuration

A transmit-array (TA)-lens-mounted hyperthermia applicator is proposed to enhance the therapeutic suitability for treatments of superficial tumors. The hyperthermia applicator, which consists of the external radiator, TA lens, and water-bolus, is designed to provide pain-free treatment of tumors. The external radiator is designed to support a uniform electromagnetic (EM) field distribution on the lens surface, and the configuration of the TA lens leads to a summation of EM energies by compensating for the phase delays for different path lengths from each elementary cell of the TA lens to the desired treatment area, which allows for optimal heat deposition at the therapeutic target. The proposed hyperthermia applicator is configured with two lenses for thermal focusing and spreading experiments. In this study, the definition of the effective treatment area (ETA) was used to evaluate thermal performance of the hyperthermia system. The calculated ETAs in two experiments (thermal focusing and spreading configurations) showed a decrease of 49% and an increase of 281%, respectively, as compared to lens-free operation.