Method for fabricating tissue-mimicking materials with designated dielectric and thermal properties for radiofrequency ablation.

Abstract

Purpose: This study presents a novel method for fabricating polyacrylamide-based tissue-mimicking materials with designated dielectric and thermal properties, designed to address the existing gap in tools that can accurately assess heat generation, transfer, and distribution during radiofrequency ablation procedures.

Methods: The dielectric and thermal properties of the materials were tuned by varying the concentrations of ethylene glycol, aluminum oxide, and sodium chloride. A total of 27 samples were fabricated, and their properties were measured at four RFA-relevant temperatures (45 °C, 60 °C, 75 °C, and 90 °C). Regression models were developed to quantitatively predict these properties based on the component concentrations. To validate the models, four additional samples were fabricated to mimic the dielectric and thermal properties of liver tissue at each of the four temperatures. Short-term stability was assessed by storing these validation samples at 4 °C for two weeks and repeating the measurements.

Results: The regression models achieved coefficients of determination (R²) above 0.87, 0.99, and 0.91 for electrical conductivity, thermal conductivity, and volumetric heat capacity, respectively. Validation experiments showed that measured properties deviated from reference liver tissue values by less than 6%, surpassing previous studies in accuracy. After two weeks of storage, relative errors remained below 10%, confirming short-term stability.

Conclusion: This study demonstrates an effective method for fabricating tissue-mimicking phantoms with designated dielectric and thermal properties, contributing to the advancement of phantoms for radiofrequency ablation research.