Trajectory control in tissue phantoms

To ablate the target tissue on demand, the accurate trajectory of the electrode is necessary. Here, to reach for certain target points, the regions of insertion positions are quantitively analyzed using the measured data in Figure 7. As shown in Figure 9A, the regions of insertion positions are plotted and compared with the total region. The insertion angle of our electrode is fixed to mimic the practical condition that might happen during an RFA. Owing to the shape tunability of our sub-electrode, the electrode tip can successfully reach the target within a wide range of insertion positions. The insertion position region is becoming smaller and moving closer to the target point with the increase of expanding speed. Such a speed-relevant characteristic might be utilized to compensate the insertion error. What’s more, the plenty choices of insertion position will help to avoid inserting into vital vessels or hurting important functional parts in the body and further reduce the possible risks that might cause during the ablation. The accurate trajectory to a certain target is verified experimentally, Figure 9B-C. Given a certain expanding speed, our electrode is able to reach the target point at different insertion positions.