Modeling of Interstitial Microwave Hyperthermia for Hepatic Tumors Using Floating Sleeve Antenna

Abstract

Background: Liver tumor, also known as hepatic tumor is one of the most common cancers with 80% of cases occurs in developing countries. Microwave hyperthermia is one of the promising treatment modalities that use microwaves to destroy the cancer cells by rising their temperature to 41- 45°C. This temperature elevation is achieved by using an applicator such as antennas. This study aims to design a microwave sleeve antenna capable of heating hepatic tumors (with different sizes and locations) to the therapeutic range of temperature for hyperthermia. Method: The sleeve antenna was designed to be resonate at 2.45 GHz and tested in a free space. Then; the antenna was tested in 6 different 3D liver models: Model A: without a tumor or blood vessels, Model B: with a tumor (2B3cm) and without blood vessels, Model C: created by adding blood vessels to model B, then a small tumor (1.5a1.5cm) was created and its location (Model D) and size (Model E) were changed. Finally, a model with a spherical tumor of 1.5 cm diameter (Model F) was tested. Results: The return loss (S-parameters) of the antenna was varied from -45 dB to -25 dB in the different liver models. The Specific Absorption Rate (SAR) reached 30W/kg in the tumor and less than 24 W/kg in the surrounding tissues, while the tumor temperature elevated to the therapeutic ranges of hyperthermia in the all models and the surrounding tissues remain at a safe temperature range. Conclusions: The obtained results showed the capability of the designed antenna to raise the temperature of hepatic tumors to the therapeutic ranges of hyperthermia.