Needle Tip Manipulation and Control of a 3D Steerable SMA-Activated Flexible Needle

Percutaneous interventions for diagnostic and therapeutic purposes such as thermal ablation, biopsy, and brachytherapy demand precise navigation of surgical needles in soft tissue towards the target. Active needle steering enhances navigation and increases target placement accuracy, and consequently improves clinical outcomes. In this work, a 3D steerable active flexible needle with multiple Shape Memory Alloy (SMA)-wire actuators is introduced. A resistive-based feedback loop control system was designed and tested to control the SMA's actuation. The needle tip position was controlled through feedback loop measurements of the electrical resistance of the SMA-wire actuators. Self-sensing capabilities of SMAs were used in the control system to realize a 3D manipulation at the needle tip. The control system performance and accuracy of the control algorithm in manipulating the 3D steerable active needle via precision control of the SMA-wire actuators was tested in reference path tracking of the needle tip.