Control of specific absorption rate distribution using capacitive electrodes and inductive aperture-type applicators:...

Area of Science:

• Biomedical Engineering
• Electromagnetics
• Medical Physics

Background:

• Radiofrequency hyperthermia requires precise control over specific absorption rate (SAR) distribution for effective cancer treatment.
• Current methods face challenges in achieving focused energy deposition, particularly with wavelengths larger than the target area.

Purpose of the Study:

• To propose and validate a novel method for controlling SAR distribution in radiofrequency hyperthermia.
• To demonstrate the feasibility of focused energy deposition using a hybrid applicator system.

Main Methods:

• A two-dimensional finite element method was employed to model current density.
• The method involves superposition of current densities from capacitively coupled electrodes and H-field coupled inductive aperture-type applicators.
• Simulations were performed on a phantom to analyze SAR distribution.

Main Results:

• The proposed method successfully modifies the current distribution within the heating material.
• Achieved "focusing" effect, increasing SAR at the phantom's center to approximately twice that of superficial regions.
• Demonstrated effective SAR control even when the electromagnetic wavelength significantly exceeds phantom dimensions.

Conclusions:

• The hybrid applicator approach offers a viable strategy for enhancing SAR focusing in radiofrequency hyperthermia.
• This technique holds potential for improving targeted heating in clinical applications.
• Further research can explore optimization and translation to in vivo models.