title: Characterization of pre-curved needles for steering in tissue.
abstract: Needles with tip asymmetry deflect upon insertion into soft tissue, an effect that can be used to steer needles within the body. This paper presents a phenomenological characterization of the steering behavior of pre-curved needles, which have tip asymmetry due to curvature of the needle near the tip. We describe needle construction methods and a needle shaft triangulation algorithm to compute the shape of the needle based on images. Experimental results show that pre-curved needles possess greater dexterity than bevel-tipped needles and achieve radii of curvature similar to pre-bent needles. For long pre-curve arc lengths, the radius of curvature of the needle was found to approach the radius of curvature of the pre-curve. Pre-curved needles were found to display behaviors not seen with bevel-tipped needles, such as the insertion velocity influencing the path of the tip within the tissue and the ability to plastically deform the needle during steering.
authors: The Johns Hopkins University Department of Mechanical Engineering, Baltimore, MD, USA.
authors: Thomas R
authors: TR
authors: Wedlick
authors: Allison M
authors: AM
authors: Okamura
mesh_terms: D000465:Algorithms; D001698:Biomedical Engineering; D004867:Equipment Design; D006801:Humans; D066298:In Vitro Techniques; D009339:Needles; D019047:Phantoms, Imaging; D012371:Robotics