Thermal ablation of hepatic tumors is recommended today as the gold standard for tumors under 3 cm in diameter. The most used method is RadioFrequency Ablation (RFA). To guide needle insertion, ultrasonography (US) is safe and radiation-free, however it remains less used than other modalities due to complex manipulation and limited vision in comparison to CT-Scans. To overcome these limitations, we develop a new 3D interface combining US plane and needle visualization in a unique 3D virtual environment. We currently use a Siemens ACUSON S3000 abdominal probe and a trakSTAR electromagnetic tracking system from NDI for tracking. Electromagnetic tracking allows us to record positions and orientations for both the needle and the US probe in real time. The system requires a one-time calibration of the probe and needle sensors. In the visualization step, we display the US image and its associated probe mesh. Additionally, we provide several guidance features to help needle insertion in and out of plane. First, the application provides a targeting system displaying the trajectory and associated distance between the needle tip and its intersection with the US plane. A pre-clinical evaluation was performed showing that our approach improved US-guided percutaneous puncture parameters compared to the standard approach.