Algorithms for Automatically Pointing Ultrasound Imaging Catheters.

A system for automatically pointing ultrasound (US) imaging catheters will enable clinicians to monitor anatomical structures and track instruments during interventional procedures. Off-the-shelf US catheters provide high quality US images from within the patient. While this method of imaging has been proven to be effective for guiding many interventional treatments, significant training is required to overcome the difficulty in manually steering the imager to point at desired structures. Our system uses closed-form four degree of freedom (DOF) kinematic solutions to automatically position the US catheter and point the imager. Algorithms for steering and imager pointing were developed for a range of useful diagnostic and interventional motions. The system was validated on a robotic test bed by steering the catheter within a water environment containing phantom objects. While the system described here was designed for pointing ultrasound catheters, these algorithms are applicable to accurate 4-DOF steering and orientation control of any long thin tendon-driven tool with single or bi-directional bending.