title: Real-Time Estimation of 3-D Needle Shape and Deflection for MRI-Guided Interventions.
abstract: We describe a MRI-compatible biopsy needle instrumented with optical fiber Bragg gratings for measuring bending deflections of the needle as it is inserted into tissues. During procedures, such as diagnostic biopsies and localized treatments, it is useful to track any tool deviation from the planned trajectory to minimize positioning errors and procedural complications. The goal is to display tool deflections in real time, with greater bandwidth and accuracy than when viewing the tool in MR images. A standard 18 ga × 15 cm inner needle is prepared using a fixture, and 350-μm-deep grooves are created along its length. Optical fibers are embedded in the grooves. Two sets of sensors, located at different points along the needle, provide an estimate of the bent profile, as well as temperature compensation. Tests of the needle in a water bath showed that it produced no adverse imaging artifacts when used with the MR scanner.
authors.affiliation: Wyss Institute for Biologically Inspired Engineering, Harvard University, Boston, MA 02115, USA.
authors.forename: Yong-Lae
authors.initials: YL
authors.lastname: Park
authors.affiliation: Center for Design Research, Department of Mechanical Engineering, Stanford University, Stanford, CA 94305, USA.
authors.forename: Santhi
authors.initials: S
authors.lastname: Elayaperumal
authors.affiliation: Department of Radiology, Stanford University, Stanford, CA 94305, USA.
authors.forename: Bruce
authors.initials: B
authors.lastname: Daniel
authors.affiliation: Center for Design Research, Department of Mechanical Engineering, Stanford University, Stanford, CA 94305, USA.
authors.forename: Seok Chang
authors.initials: SC
authors.lastname: Ryu
authors.affiliation: Center for Design Research, Department of Mechanical Engineering, Stanford University, Stanford, CA 94305, USA.
authors.forename: Mihye
authors.initials: M
authors.lastname: Shin
authors.affiliation: Howard Hughes Medical Institute, Chevy Chase, MD 20815 USA, and also with the Center for Design Research, Department of Mechanical Engineering, Stanford University, Stanford, CA 94305, USA.
authors.forename: Joan
authors.initials: J
authors.lastname: Savall
authors.affiliation: Intelligent Fiber Optic Systems (IFOS) Corporation, Santa Clara, CA 95054, USA.
authors.forename: Richard J
authors.initials: RJ
authors.lastname: Black
authors.affiliation: Intelligent Fiber Optic Systems (IFOS) Corporation, Santa Clara, CA 95054, USA.
authors.forename: Behzad
authors.initials: B
authors.lastname: Moslehi
authors.affiliation: Center for Design Research, Department of Mechanical Engineering, Stanford University, Stanford, CA 94305, USA.
authors.forename: Mark R
authors.initials: MR
authors.lastname: Cutkosky
keywords: Biomedical transducers; Bragg gratings; biopsy; magnetic resonance imaging (MRI); optical fiber sensors; strain measurement