Radiofrequency ablation using perfused needle electrodes - study of intermittent and continuous triple needle application ex vivo.

To increase necrotic zones, bovine livers were treated by means of three parallel-oriented radiofrequency ablation (RFA) needles spaced at 3 cm using a puncture guide. The triple application was varied as a continuous and intermittent energy application compared to a single needle applicator. In all three study arms the applied energy (60 W) and the perfusion rate (240 ml/h) were kept constant. After treatment the smallest necrosis diameter was determined. In addition, temperature and the device's power output were monitored. Our study shows that synchronous use of three RFA application needles achieves significantly larger necrosis zones ex vivo than does single needle application. Intermittent energy application heats up the necrosis faster and more evenly with highest average temperature than continuous energy application.