Current Density Distribution. Plot of the current density along the active portion of the radiofrequency ablation probe when a source voltage of 20.0 volts is applied. The highest current density corresponds to the proximal edge. The figure shows that in all cases where perfusion is accounted for fall between the model results for temperature-dependent and constant electrical conductivity with no perfusion. Note: Constant conductivity with (green) and without (red) tissue perfusion overlap.