Thermal modeling for pulsed radiofrequency ablation: analytical study based on hyperbolic heat conduction

Area of Science:

• Biomedical Engineering
• Thermal Physics
• Electrophysiology

Background:

• Pulsed radiofrequency (RF) heating is crucial in medical applications.
• Understanding thermal wave behavior in biological tissues is essential for safety and efficacy.
• Fourier-based heat transfer models may not fully capture transient thermal phenomena.

Purpose of the Study:

• To model temperature distribution during pulsed RF heating of biological tissue.
• To employ the hyperbolic heat transfer equation (HHTE) accounting for thermal wave behavior.
• To compare HHTE results with those from the Fourier-based heat transfer equation (FHTE).

Main Methods:

• Development of a theoretical model with a spherical electrode embedded in biological tissue.
• Analytical solutions for both HHTE and FHTE were derived.
• Analysis of temperature waveforms based on dimensionless parameters like pulse duration, thermal relaxation time, and position.

Main Results:

• Identified three typical temperature waveforms dependent on RF pulse parameters.
• Observed temperature peaks traveling at finite speeds in the HHTE solution, occurring during both power on and off.
• Demonstrated that temperature profiles result from overlapping delayed heat sources.

Conclusions:

• HHTE provides a more comprehensive model for pulsed RF heating by capturing thermal wave dynamics.
• The study offers a physical explanation for traveling temperature peaks via thermal wave interactions.
• Developed versatile analytical solutions for FHTE and HHTE applicable to various pulsing frequencies and duty cycles.