Synchronization of a Surgical Robot With a Dynamic Surgical Target Using Three-Dimensional Ultrasound

A robotic system is presented that uses threedimensional ultrasound to visually servo a surgical instrument. Tracking of both the surgical instrument and a target was done using image based algorithms on the real-time 3D ultrasound data. The tracking techniques are shown to be especially amenable for execution on powerful graphics processor units. By harnessing a graphics card, it was possible to detect both a surgical instrument and a surgical target at a rate of 25 Hz. The high update rate permits the use of tracked instrument and target locations for controlling a robot. Validation of the system was done in a water tank. The robot successfully tracked a target moving at speeds mimicking a mitral valve within a beating heart. During the trials the robot accurately moved the surgical instrument with maximum errors of 3.9 mm and RMS error of 1.2 mm.