Heat sink effects in thyroid bipolar radiofrequency ablation: an ex vivo study

Figures

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  Figure 1. Experimental setup (A) for bipolar RFA in ex vivo bovine thyroid samples, maintained at body temperature in an incubator, with variable perfusion rates applied to the ablation zone. (B) Cross-section of the ablation zone showing the glass tube position. Equidistant placement of thermocouples in relation to the applicator near the vessel (TV) and in the contralateral half of the ablation zone (TC).

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  Figure 2. Sample cross-section images of the ablation zone at perfusion rates of 0, 0.5, and 20 ml/min. Measurements of the ablation zone area (red dotted line) and lateral penetration depth (blue line). Decrease of dV with increasing flow rates, while dC remains unchanged.

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  Figure 3. Temperature analysis. Maximum temperatures at different flow rates for 10 W (A) and 25 W (B). TV: thermocouple in the vicinity of the vessel, TC: thermocouple on the non-perfused side of the ablation zone (control). *p < 0.05, **p < 0.01, ns p > 0.05.

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  Figure 4. Cross-section analysis. Ablation zone area at different flow rates at 10 W (A) and 25 W (B). Penetration depth (d) on both the vessel and contralateral side at different flow rates with power levels set to 10 W (C) and 25 W (D). *p < 0.05, **p < 0.01.

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  Figure 5. Regression analysis of flow rate impact on temperature and ablation zone area at power level settings of 10 W and 25 W. Trendline of temperature on the vessel side and the contralateral as a function of flow rate at a power level setting of 10 W (A) and 25 W (B). (C) relationship between flow rate and the ablation zone area at both power level settings of 10 W and 25 W.