Planning active cannula configurations through tubular anatomy

Medical procedures such as lung biopsy and brachytherapy require maneuvering through tubular structures such as the trachea and bronchi to reach clinical targets. We introduce a new method to plan configurations for active cannulas, medical devices composed of thin, pre-curved, telescoping lumens that are capable of following controlled, curved paths through open or liquid-filled cavities. Planning optimal configurations for these devices is challenging due to their complex kinematics, which involve both beam mechanics and space curves. In this paper, we propose an optimization-based planning algorithm that computes active cannula configurations through tubular structures that reach specified targets. Given the target location, the start position and orientation, and a geometric representation of the physical environment extracted from pre-procedure medical images, the planner optimizes insertion length and orientation angle of each lumen of the active cannula. The planner models active cannula kinematics using a physically-based simulation that incorporates beam mechanics and minimizes energy. The algorithm typically computes plans in less than 2 minutes on a standard PC. We apply the method in simulation to anatomy extracted from a human CT scan and demonstrate configurations for a 5-lumen active cannula that maneuver it through the bronchi to targets in the lung.