Figure 4b:

(a) In vivo intraprocedural CT images of monopole (left) and dual slot (right) antennas show differences in hypoattenuating area corresponding to vapor formation around heating element. Hypoattenuating region outlines appear on the right of each CT image. (b) Graph shows comparison of the hypoattenuating cross-sectional areas of dual-slot and monopole antennas at 1-minute intervals. (c) Gross histologic examination shows hypoattenuating region demarcating area of central desiccation in ablation zone. Dual-slot antenna is capable of maintaining hypoattenuating region of growth longer and of creating overall larger hypoattenuating area compared with that of monopole antenna.