A needle tracking device for ultrasound guided percutaneous procedures.

A novel tracking device is proposed for measuring the position and orientation of a needle with respect to an ultrasound probe. This device is intended to guide an operator during a percutaneous needle insertion so that the needle trajectory can be visually aligned with the target before insertion. The tracking device uses a pair of cameras to track the needle location so that a standard needle can be used without attaching a separate sensor to the needle. The main challenge is to calibrate the tracking system with sufficient accuracy. Calibration methods are described for each of the system parameters. A series of tests show that an overall error of 3.1 +/- 1.8 mm is achieved with two commercial cameras and an error of 6.5 +/- 5.7 mm is achieved with two inexpensive consumer cameras. An analysis of the source of errors reveals that the errors arise from all of the calibration steps. Overall system accuracy is therefore determined by both the quality of the cameras and the performance of calibration.