Temperature Distribution of Radiofrequency Hyperthermia in a Capacitance System in Breast Equivalent Tumor Ablation: A Simulation Study

For decades, hyperthermia had been widely used for tumor ablation by increasing the temperature of cancerous tissues. For clinical treatment, a capacitance system was developed around the world. In this study, a capacitance system of radiofrequency (RF) hyperthermia was simulated to achieve the temperature distribution map of the entire breast equivalent phantom. Therefore, the efficiency of this method in the treatment of breast cancer was investigated in the current study.

In this study, an RF system with a frequency of 13.56 MHz was simulated by Comsol Multiphysics software (Version 5.3). The geometry of the breast cancerous tissue was modeled by the consideration of three different tissues, including the fat, gland, and tumor tissues. The two electrodes of the system were modeled as two disks with a radius of 15 cm. The calculations of the RF wave and bioheat equation were accomplished by numerical simulation and finite element method.

The temperature plots were obtained in 5 min. The temperature distribution map was entirely achieved and the results were compared with experimental findings to check the accuracy of the RF device and precision of the thermometer.

The obtained results showed that the temperature of the whole tumor region increased uniformly (3-4˚C). Moreover, the temperature of the whole healthy tissues (i.e., the gland and fat tissues) did not increase (1.9-2.1˚C). Consequently, in the capacitive hyperthermia system, the tumor reached extreme heat; however, the healthy tissues were completely protected from damages.