Heat Transfer Study in Breast Tumor Phantom during Microwave Ablation: Modeling and Experimental Results for Three Different Antennas

Abstract

It is worldwide known that the most common type of cancer among women is breast cancer. Traditional procedures involve surgery, chemotherapy and radiation therapy; however, these treatments are invasive and have serious side effects. For this reason, minimally invasive thermal treatments like microwave ablation are being considered. In this study, thermal behavior of three types of slot-coaxial antennas for breast cancer microwave ablation is presented. By using finite element method (FEM), all antennas were modeled to estimate the heat transfer in breast tumor tissue surrounded by healthy breast tissue. Experimentation was carried out by using the antennas inserted inside sphere-shaped-tumor phantoms with two different diameters, 1.0 and 1.5 cm. A microwave radiation system was used to apply microwave energy to each designed antenna, which were located into the phantom. A non-interfering thermometry system was used to measure the temperature increase during the experimentation. Temperature increases, recorded by the thermal sensors placed inside the tumor phantom surrounded by healthy breast phantom, were used to validate the FEM models. The results conclude that, in all the cases, after 240 s, the three types of coaxial slot antenna reached the temperature needed produce hyperthermia of the tumor volume considered in this paper.

Modeling of heat transfer distribution in tumor breast cancer during microwave ablation therapy

“…The temperature distribution is analogous to that obtained by Ortega-Palacios et al 24 The maximum temperature reached in each is also comparable.…”

“…In the case of a double‐slot antenna, the spacing between the slots is given according to the effective wavelength in the tissue at the operating frequency f . This quantity is estimated by 23 $$${\lambda }_{\mathrm{eff}}=\frac{c}{f\sqrt{{\varepsilon }_{r}}},$$$where $$c$$ represents the vacuum speed of light and $${\varepsilon }_{r}=57$$ is the relative permittivity of the breast cancer tissue 24 . The slot spacing length is equal to $${0.25\lambda }_{\mathrm{eff}}$$.…”

“…where c represents the vacuum speed of light and ε = 57 r is the relative permittivity of the breast cancer tissue. 24 The slot spacing length is equal to λ 0.25 eff . In other terms, its value is 4.2 mm.…”

A review of antenna designs for percutaneous microwave ablation

“…To describe the magnitude of the wavelength that propagates through the tissue, the effective wavelength (λ eff ) is introduced, which is defined as [80,81]:…”

Microwave Hyperthermia Application with Bioimplant Single Slot Coaxial Antenna Design for Mouse Breast Cancer Treatment

“…However, electrical engineers and microwave and RF technology also play a key role in this area. In most of the studies such as [20][21][22], important design parameters, such as the electrical characterization of the radiating antenna, reflection coefficient graphics, farfield radiation, SAR values on the tissue and other primary details that concern the engineers who will make the design, are not given sufficiently. In many studies showing details about the engineering aspects, publications are mostly limited to theoretical or simulation, antenna fabrication or measurements for application are not given [23][24][25][26][27] or the proposed designs are costly, far from being compact or production techniques of them are not suitable for mass production [25,26,[28][29][30].…”