Robotically Adjustable Magnetic Navigation System and Magnetic Catheter Robot for Vascular Intervention

Abstract

Magnetic robots manipulated by a magnetic navigation system are currently being widely investigated due to their strong technical advantages. Specifically, magnetic robots can be remotely manipulated without power cables, and they have a very simple structure because only an embedded magnet is required for manipulation. Given these strong advantages, magnetic robots and magnetic navigation systems are considered promising applications for vascular interventions. However, conventional magnetic robots and magnetic navigation systems have several limitations in this context. To overcome these limitations, a novel concept of a robotically adjustable magnetic navigation system (RAMNS) and magnetic catheter robot (MCR) are developed in this dissertation. The RAMNS is composed of an electromagnet and a linear robot stage, and it can adjust size and position of its workspace with respect to the application region. Herein, the structure of the electromagnet and the linear robot stage, the optimized design method of the electromagnet, and the integrated control method are described, and their performance and effectiveness are verified by several experiments utilizing a constructed prototype. The multifunctional MCR is proposed for various functions of vascular intervention, such as active steering, tunneling, drug delivery, and stent delivery motions. The MCR is composed of a tube, a magnetic joint for selective motions, tension springs, a self-expandable stent, a stent mounting body, a front magnet, and a drill tip. The structure, the manipulation methods for each motion, the dynamic constraints for selective motions, and the design methods for the magnetic joint and tension springs are described. The effectiveness of its each motion and selective motion control method are verified by several experiments, including in vitro experiments with a pseudo-vascular environment and blood clot. According to the results, the developed RAMNS and the multifunctional MCR were able to overcome the limitations of conventional MNSs and magnetic robots and satisfy enough performances for vascular interventions. Therefore, they can be applied to actual vascular intervention operations and can contribute to the technical advancement of magnetic navigation system and magnetic robot research.