title: Needle Steering in 3-D Via Rapid Replanning.
abstract: Steerable needles have the potential to improve the effectiveness of needle-based clinical procedures such as biopsy and drug delivery by improving targeting accuracy and reaching previously inaccessible targets that are behind sensitive or impenetrable anatomical regions. We present a new needle steering system capable of automatically reaching targets in 3-D environments while avoiding obstacles and compensating for real-world uncertainties. Given a specification of anatomical obstacles and a clinical target (e.g., from preoperative medical images), our system plans and controls needle motion in a closed-loop fashion under sensory feedback to optimize a clinical metric. We unify planning and control using a new fast algorithm that continuously replans the needle motion. Our rapid replanning approach is enabled by an efficient sampling-based rapidly exploring random tree (RRT) planner that achieves orders-of-magnitude reduction in computation time compared with prior 3-D approaches by incorporating variable curvature kinematics and a novel distance metric for planning. Our system uses an electromagnetic tracking system to sense the state of the needle tip during the procedure. We experimentally evaluate our needle steering system using tissue phantoms and animal tissueex vivo. We demonstrate that our rapid replanning strategy successfully guides the needle around obstacles to desired 3-D targets with an average error of less than 3 mm.
authors.affiliation: Department of Electrical Engineering and Computer Science, University of California, Berkeley, CA 94709 USA ( sachinpatil@berkeley.edu ).
authors.forename: Sachin
authors.initials: S
authors.lastname: Patil
authors.affiliation: Hannover Center of Mechatronics, Leibniz Universität Hannover, Hanover 30167, Germany ( burgner@mzh.uni-hannover.de ).
authors.forename: Jessica
authors.initials: J
authors.lastname: Burgner
authors.affiliation: Department of Mechanical Engineering, Vanderbilt University, Nashville, TN 37235 USA ( robert.webster@vanderbilt.edu ).
authors.forename: Robert J
authors.initials: RJ
authors.lastname: Webster
authors.affiliation: Department of Computer Science, University of North Carolina, Chapel Hill, NC 27514 USA ( ron@cs.unc.edu ).
authors.forename: Ron
authors.initials: R
authors.lastname: Alterovitz
keywords: Medical robotics; needle steering