Establishment of a Tissue-Mimicking Surrogate for Pulmonary Lesions to Improve the Development of RFA Instruments and Algorithms

• Published in: Biomedicines 2022-05, Vol.10 (5), p.1100
• Main Authors: Bühler, Louisa, Enderle, Markus D, Kahn, Nicolas, Polke, Markus, Schneider, Marc A, Heußel, Claus Peter, Herth, Felix J F, Linzenbold, Walter
• Format: Article
• Language: English
• Subjects: Ablation; agar; Algorithms; Chloride; Electrical impedance; Electrical properties; Electrodes; Liver; Lung cancer; Lungs; Mimicry; Pulmonary lesions; Radiofrequency ablation; Sheep; Sodium; Sodium chloride; Software; thermochromic; tissue-mimicking phantom; Tumors; Yolk
• ISSN: 2227-9059; 2227-9059
• DOI: 10.3390/biomedicines10051100

(1) Development of radiofrequency ablation (RFA) systems for pulmonary lesions is restricted by availability of human tumor specimens and limited comparability of animal tissue. We aimed to develop a new surrogate tissue overcoming these drawbacks. (2) Reference values for electrical impedance in lung tumor tissue were collected during routine lung tumor RFA (n = 10). Subsequently, a tissue-mimicking surrogate with comparable electrical impedance and facilitating detection of the ablation margins was developed. (3) The mean electrical impedance for all patients was 103.5 ± 14.7 Ω. In the optimized surrogate tissue model consisting of 68% agar solution, 23% egg yolk, 9% thermochromic ink, and variable amounts of sodium chloride, the mean electrical impedance was adjustable from 74.3 ± 0.4 Ω to 183.2 ± 5.6 Ω and was a function (y = 368.4x + 175.2; R2 = 0.96; p < 0.001) of sodium chloride concentration (between 0 and 0.3%). The surrogate tissue achieved sufficient dimensional stability, and sample cuts revealed clear margins of color change for temperatures higher 60 °C. (4) The tissue-mimicking surrogate can be adapted to lung tumor with respect to its electrical properties. As the surrogate tissue allows for simple and cost-effective manufacturing, it is suitable for extensive laboratory testing of RFA systems for pulmonary ablation.