Integrated Magnetic Location Sensing and Actuation of Steerable Robotic Catheters for Peripheral Arterial Disease Treatment

Magnetically steerable robotic catheters (MSRC) are a promising technology for percutaneous endovascular intervention (PEI) procedures to treat peripheral arterial diseases (PAD), where magnetic actuation is used to steer the catheter tip during navigation. However, today's MSRC systems require fluoroscopic imaging for catheter location sensing during the procedure, which risks creating radiation-induced injuries to both the patient and the radiologist. Aiming to reduce the duration of x-ray radiation in interventions using MSRCs, this letter introduces a new type of steerable robotic catheter system that integrates magnetic location sensing and magnetic actuation. The proposed catheter uses a magnetic tip to enable steering by external electromagnetic actuators. In addition, a cylindrical array of magnetic sensors is used to measure the field from the catheter tip to enable real-time catheter location estimation. To enable improved localization accuracy, a novel nested calibration algorithm for sensor positions and magnet dipole strength is introduced. This letter further proposes a novel integration method for magnetic actuation and magnetic location sensing in MSRC systems, where fluoroscopic imaging is only required during catheter steering at bifurcations in the vasculatures, which effectively reduces x-ray radiation in the navigation process of catheters. The proposed methodology is tested with an MSRC prototype, where a ring-shaped magnet (3 mm OD, 1.6 mm ID, 6 mm length) is arranged at the catheter tip for actuation and location sensing. The magnet location estimation algorithm is implemented for real-time visual feedback to the operator with a low latency of 400 ms. Experiments show that an average position estimation error of 0.95 mm can be achieved after calibrating the system using the proposed algorithm. The prototype catheter can successfully navigate through phantoms of vasculatures under a combination of magnetic steering and magnetic location sensing, which shows the excellent potential of the proposed framework for reducing x-ray exposure in PAD interventions.