P5C-4 Image Guidance Using Camera and Ultrasound Images

Previous work of estimating needle trajectories using un-calibrated camera-based tracking ("touchless" needle guide) is extended here to real ultrasound imaging. Using 4D ultrasound, this technique can be used as a needle guide during percutaneous procedures. A pair of miniature cameras captures images and the ultrasound system captures a volume as the needle moves through the workspace. The 2D position and orientation of the needle is calculated from the camera images and the 3D position of the needle is estimated from the ultrasound volume. A database is created from these values and a non-parametric learning algorithm determines the best model to the data. Then, in practice, the model can be used to estimate the projected needle trajectory within the ultrasound volume with only camera images of the needle above the skin surface. This study achieved an average error of 0.94 mm in position and 3.93deg in orientation.