Surgical robots provide many advantages for surgery, including minimal invasiveness, precise motion, high dexterity,
and crisp stereovision. One limitation of current robotic procedures, compared to open surgery, is the loss of haptic
information for such purposes as palpation, which can be very important in minimally invasive tumor resection.
Numerous studies have reported the use of real-time ultrasound elastography, in conjunction with conventional B-mode
ultrasound, to differentiate malignant from benign lesions. Several groups (including our own) have reported integration
of ultrasound with the da Vinci robot, and ultrasound elastography is a very promising image guidance method for robotassisted
procedures that will further enable the role of robots in interventions where precise knowledge of sub-surface
anatomical features is crucial. We present a novel robot-assisted real-time ultrasound elastography system for minimally
invasive robot-assisted interventions. Our system combines a da Vinci surgical robot with a non-clinical experimental
software interface, a robotically articulated laparoscopic ultrasound probe, and our GPU-based elastography system.
Elasticity and B-mode ultrasound images are displayed as picture-in-picture overlays in the da Vinci console. Our system
minimizes dependence on human performance factors by incorporating computer-assisted motion control that
automatically generates the tissue palpation required for elastography imaging, while leaving high-level control in the
hands of the user. In addition to ensuring consistent strain imaging, the elastography assistance mode avoids the
cognitive burden of tedious manual palpation. Preliminary tests of the system with an elasticity phantom demonstrate the
ability to differentiate simulated lesions of varied stiffness and to clearly delineate lesion boundaries.