Electro Thermomechanical Behavior of a Smart Actuator for an Active Surgical Needle

A large and increasing number of cancer interventions, including both diagnosis and therapy, involve precise placement of needles. The challenge in most of the existing needle-based procedures is the safe and accurate navigation of the needle through tissue to the desired target. This challenge is due to lack of proper actuation of the needle (i.e., actuated from the proximal end, which is far away from the needle tip). To overcome this challenge, we propose to bend the needle using a smart actuator that applies bending forces on the needle body; thereby, improving the navigation of the needle. The smart actuator is designed with shape memory alloy (SMA) wires due to their unique properties such as superelasticity, shape memory effect, and biocompatibility. These wires, connected on the needle, can be heated with resistance heating to produce relatively large forces that can bend the needle. However, predicting the actuation forces is difficult due to their coupled thermomechanical effects. Therefore, this study will experimentally and numerically evaluate the feasibility of the SMA wires for the smart actuator.