Ultrasound-based servoing of manipulators for telesurgery

Certain minimally invasive surgical procedures involve the treatment of highly precise target locations within deformable tissues. While preoperative MRI and CT models can be used for surgical planning, they provide only coarse guidance during surgery due to their limited resolution and owing to tissue deformation. Ultrasound imaging is a promising means of obtaining real-time intraoperative data for target localization that is particularly well suited to minimally invasive surgery due to its portability, speed, and safety. This paper presents a system, in which ultrasound images are used to guide a manipulator to a surgical site. Electromagnetic tracking of the ultrasound probe is used to orient the images. These are then segmented in real time to determine target locations. Finally, target coordinates are used to produce control inputs to drive the manipulator to the target site. The potential of the approach is demonstrated experimentally using a manipulator arm, phantom target, and commercial ultrasound machine.