A Taguchi-optimized agar phantom for temperature-based validation in electro-hyperthermia

Area of Science:

• Biomedical Engineering
• Medical Physics
• Materials Science

Background:

• Quality assurance (QA) is crucial for electro-hyperthermia (EHY) systems.
• Accurate temperature monitoring is essential for effective EHY treatment.
• Developing reliable phantoms for QA is an ongoing challenge.

Purpose of the Study:

• To develop and optimize an agar-based phantom for temperature-based validation of EHY systems.
• To establish a QA framework for EHY devices using the developed phantom.
• To compare phantom heating profiles with biological tissue.

Main Methods:

• Utilized the Taguchi method with an orthogonal array to design nine agar phantom formulations.
• Varied concentrations of agar, sodium chloride (NaCl), and sodium azide (NaN₃).
• Heated phantoms using the Oncotherm EHY-2000 device and measured temperature at 5 cm depth.

Main Results:

• Identified an optimal formulation (5.0% agar, 0.1% NaCl, 0.44% NaN₃) closely resembling pork tissue temperature profiles.
• Taguchi analysis revealed agar concentration as the most significant factor influencing temperature.
• Found weak interactions among formulation variables, allowing independent optimization.

Conclusions:

• The developed agar phantom is simple to fabricate, reusable, and storable.
• It serves as a practical tool for detecting abnormal heating in EHY devices.
• The phantom is suitable for routine QA of the Oncotherm EHY system, enhancing treatment safety and accuracy.