Breathing Compensation in Magnetic Robotic Bronchoscopy via Shape Forming

Despite the increased interest in robotic systems designed for bronchoscopy, the influence of the bronchial tree dynamics remains relatively unexplored. To enable robotic solutions to perform successful autonomous navigations whilst minimizing contact with the internal anatomy, they must be capable of adapting to ongoing geometric changes caused by the respiratory cycle. In this letter, we introduce a method for parameterizing these cyclic changes and present a flexible magnetic robotic catheter design that adapts its shape dynamically. Three bronchial branches (up to 4th generation bronchioles) with diverse shapes were investigated to examine the feasibility and efficacy of this approach. Reference anatomical geometry was taken from an open-source dynamic computed tomography patient dataset, and was evaluated over the breathing cycle to develop patient- and branch-specific magnetic catheter profiles and associated time-varying external magnetic fields. The system was demonstrated using dynamic Helmholtz coil actuation and showed a mean error in replicating the centerline of each of the three branches over the entire navigation of 2.1 mm, 1.4 mm, and 1.9 mm respectively.