Modeling and validation of microwave ablations with internal vaporization

Area of Science:

• Biomedical Engineering
• Medical Physics
• Computational Modeling

Background:

• Numerical simulations are crucial for designing medical treatments and planning procedures.
• Existing models often lack crucial physics like water vaporization and mass transfer, especially during microwave heating.
• These omissions limit the accuracy of simulations for thermal ablation therapies.

Purpose of the Study:

• To develop and validate a numerical model that integrates microwave heating with water vapor generation and transport.
• To assess the model's accuracy in predicting ablation size and shape.
• To improve the computational tools used for planning and analyzing microwave ablation procedures.

Main Methods:

• A numerical model was developed using porous media assumptions to simulate tissue heating and water vapor transport.
• Model heating physics were validated via temperature measurements in ex vivo bovine liver.
• Ablation zone dimensions were validated by comparing CT-derived iso-density contours with model-predicted vapor concentration contours using the Jaccard index.

Main Results:

• The numerical model successfully integrated microwave heating with water vapor generation and transport.
• Temperature measurements validated the heating physics of the model.
• Jaccard indices showed improving correlation between simulated and actual ablation sizes over time (0.27 to 0.69 from 1 to 5 minutes).

Conclusions:

• Incorporating water vapor concentration into thermal ablation simulations is feasible and improves model accuracy.
• The validated model provides a more comprehensive tool for computer-aided design and clinical treatment planning in microwave ablation.
• Experimental validation is essential for confirming the reliability of advanced numerical models in medical applications.