Resolution Optimal Motion Planning for Medical Needle Steering from Airway Walls in the Lung

Steerable needles are novel medical devices capa-ble of following curved paths through tissue, enabling them to avoid anatomical obstacles and steer to hard-to-reach sites in tissue, including targets in the lung for lung cancer diagnosis. Steerable needles are typically deployed into tissue from an insertion surface, and selecting the insertion site is critical for procedure success as it determines which paths the needle can take to its target. Prior motion planners for steerable needles typically only plan from a specific start pose to the target. We introduce a new resolution-optimal steerable needle motion planner that efficiently finds plans from an insertion surface to a target position, handling additional degrees of freedom at both the start and the target. Our algorithm systematically builds a search tree consisting of needle motion primitives backward from the target towards the insertion surface, which allows it to provide an optimality guarantee up to the resolution of the primitives. The algorithm finds higher-quality plans faster than prior state-of-the-art motion planners, as demonstrated in anatomical scenario simulations in the lung.