Quality assurance phantoms for deep hyperthermia devices: design principles informed by computational modeling

Area of Science:

• Medical Physics
• Biomedical Engineering
• Oncology

Background:

• Accurate thermal dose delivery is crucial for deep hyperthermia (DHT) clinical success.
• The European Society for Hyperthermic Oncology (ESHO) is transitioning to temperature-based quality assurance (QA) metrics.
• Standardized tissue-mimicking phantoms are increasingly important for DHT QA.

Purpose of the Study:

• To provide quantitative evidence for designing standardized DHT phantoms.
• To guide phantom design using computational modeling and experimental validation.
• To support temperature-based QA procedures for DHT.

Main Methods:

• Numerical simulations of a clinical DHT applicator at 75 and 100 MHz.
• Parametric studies on phantom geometry and dielectric properties (permittivity, conductivity).
• Experimental validation using a gel phantom and comparison with patient models.

Main Results:

• Electrical conductivity significantly impacts heating patterns and temperature gradients in phantoms.
• Simulations showed good agreement with patient models in the focal region.
• Experimental measurements closely matched simulated temperatures, with average deviations of 0.7 ± 0.5 °C.

Conclusions:

• A validated modeling framework and design recommendations for DHT QA phantoms are established.
• Understanding phantom parameter influence on temperature profiles enhances QA reliability.
• Quantifying uncertainties supports the development of standardized QA phantoms for clinical DHT systems.