RF field visualization of RF ablation at the Larmor frequency

Area of Science:

• Medical Physics
• Oncology
• Biomedical Engineering

Background:

• Radio-frequency ablation (RFA) is a minimally invasive tumor treatment with challenges in monitoring and controlling the ablation zone.
• Current RFA at 460 kHz can be monitored by MRI for temperature and visualization, but direct RF field visualization is limited.
• Controlling ablation currents is crucial for lesion shape, size, and repeatability.

Purpose of the Study:

• To investigate the feasibility of performing RFA at 64 MHz, the MRI Larmor frequency.
• To explore the use of MR B(1) field mapping for direct visualization of RF fields generated during ablation.
• To assess if visualizing RF fields can improve control over the ablation process.

Main Methods:

• Performed radio-frequency ablation (RFA) at 64 MHz.
• Utilized MR B(1) field mapping to image the radio-frequency fields produced by the ablation currents.
• Analyzed changes in current density within the ablated region post-procedure.

Main Results:

• Demonstrated the feasibility of conducting RFA at 64 MHz.
• Successfully imaged the RF fields generated during the 64 MHz ablation.
• Observed an increased current density in the ablated region, indicating altered tissue conductivity.

Conclusions:

• Performing RFA at the MRI Larmor frequency (64 MHz) is feasible.
• Direct visualization of RF fields via MR B(1) mapping shows potential for enhanced ablation control.
• Increased conductivity in ablated tissue, evidenced by current density changes, supports improved lesion monitoring.