Mobile Ultrasound Tracking and Magnetic Control for Long‐Distance Endovascular Navigation of Untethered Miniature Robots against Pulsatile Flow

Abstract

Long‐distance endovascular navigation of miniature robots under the guidance of medical imaging modalities is essential for microrobotic targeted delivery in the human body. Herein, a scheme on this topic based on mobile ultrasound (US) tracking and magnetic control is proposed. Considering the narrow 2D imaging of a US probe and the fast decay of the magnetic field, the US probe is integrated with three electromagnetic coils for simultaneous long‐distance tracking and control of untethered miniature robots. To enable robust tracking with pulsatile flow, a tracking strategy consisting of tracking in and perpendicular to the image plane is designed. In the image plane, an iterative statistics‐based strategy is proposed to extract the position and orientation of the robot from the US imaging. For the direction perpendicular to the US image plane, the probe motion is automatically adjusted according to the tracking quality. Based on the real‐time tracking result, demanded rotating fields are generated by the mobile coils for helical propulsion. The proposed scheme is implemented on a full‐scale silicone phantom of human iliac and aorta arteries with blood‐mimicking fluid and pulsatile flow. Experimental results validate the robustness and the effectiveness of the proposed scheme.

Keywords

• endovascular navigation
• magnetic control
• microrobots
• ultrasound imaging