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Proceedings Paper

Registration of a needle-positioning robot to high-resolution 3D ultrasound and computed tomography for image-guided interventions in small animals
Author(s): Adam C. Waspe; James C. Lacefield; David W. Holdsworth; Aaron Fenster
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Paper Abstract

Preclinical research often requires the delivery of biological substances to specific locations in small animals. Guiding a needle to targets in small animals with an error < 200 μm requires accurate registration. We are developing techniques to register a needle-positioning robot to high-resolution three-dimensional ultrasound and computed tomography small animal imaging systems. Both techniques involve moving the needle to predetermined robot coordinates and determining corresponding needle locations in image coordinates. Registration accuracy will therefore be affected by the robot positioning error and is assessed by measuring the target registration error (TRE). A point-based registration between robot and micro-ultrasound coordinates was accomplished by attaching a fiducial phantom onto the needle. A TRE of 145 μm was achieved when moving the needle to a set of robot coordinates and registering the coordinates to needle tip locations determined from ultrasound fiducial measurements. Registration between robot and micro-CT coordinates was accomplished by injecting barium sulfate into tracks created when the robot withdraws the needle from a phantom. Points along cross-sectional slices of the segmented needle tracks were determined using an intensity-weighted centroiding algorithm. A minimum distance TRE of 194 ± 18 μm was achieved by registering centroid points to robot trajectories using the iterative closest point (ICP) algorithm. Simulations, incorporating both robot and ultrasound fiducial localization errors, verify that robot error is a significant component of the experimental registration. Simulations of micro-CT to robot ICP registration similarly agree with the experimental results. Both registration techniques produce a TRE < 200 μm, meeting design specification.

Paper Details

Date Published: 17 March 2008
PDF: 12 pages
Proc. SPIE 6918, Medical Imaging 2008: Visualization, Image-Guided Procedures, and Modeling, 691807 (17 March 2008); doi: 10.1117/12.770449
Show Author Affiliations
Adam C. Waspe, Robarts Research Institute (Canada)
Univ. of Western Ontario (Canada)
James C. Lacefield, Robarts Research Institute (Canada)
Univ. of Western Ontario (Canada)
David W. Holdsworth, Robarts Research Institute (Canada)
Univ. of Western Ontario (Canada)
Aaron Fenster, Robarts Research Institute (Canada)
Univ. of Western Ontario (Canada)

Published in SPIE Proceedings Vol. 6918:
Medical Imaging 2008: Visualization, Image-Guided Procedures, and Modeling
Michael I. Miga; Kevin Robert Cleary, Editor(s)

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