Enabling Autonomous Ultrasound-Guided Tumor Ablation During Robotic Surgery

While technologies such as cryo- or radio-frequency ablation allow for less invasive treatment of tumors than re-section, they still require needles to reach the target location with the potential risk of spreading tumor tissue around. High Intensity Focused Ultrasound (HIFU) on the other hand allows for a completely remote and concentrated delivery of energy to a target location without the need for direct access and is particularly well suited to be robotically guided and thus used as part of an autonomous system. While robotic HIFU devices have been extensively explored for extracorporeal applications, their application into a laparoscopic setting is still widely unexplored. This paper presents a novel robotic HIFU pick-up device along with an automated workflow that includes the autonomous acquisition of the tumor geometry via Ultrasound (US) imaging, trajectory planning and autonomous execution of the HIFU ablation constraint by the tissue surface. Therefore, a novel sensorised water-filled membrane is developed and evaluated, enabling hybrid force position control that allows for minimising interaction forces with the tissue surface while maintaining sufficient acoustic coupling for ablation. Experiments on a phantom with a HIFU probe dummy demonstrate the effectiveness of the approach in targeting hidden structures.