Effect of perfusion distance on energy deposition into the tissue. Three perfusion distances were tested: 0 mm (n = 7), 2 mm (n = 12) and 4 mm (n = 16). Scatter plot shows non-linear (quadratic) relationship between distance and deposited power (A). Goodness of fit of the model is assessed by r2. Note the improved effect at perfusion distance of 2 mm on deposition of power. Additionally, a drop-line chart (B) summarizes the observed relative frequency of an uncontrolled rise of impedance within two RFA durations (10 and 20 min) for the three values of perfusion distance. Note the lower rate of impedance rise during the procedure at a distance of 2 mm. In all cases, longer durations (20 minutes) were linked to a higher rate of impedance rise.