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Proceedings Paper

Motorized fusion guided prostate biopsy: phantom study
Author(s): Reza Seifabadi; Sheng Xu; Fereshteh Aalamifar; Peter Pinto; Bradford J. Wood
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Paper Abstract

Purpose: Fusion of Magnetic Resonance Imaging (MRI) with intraoperative real-time Ultrasound (US) during prostate biopsy has significantly improved the sensitivity of transrectal ultrasound (TRUS) guided cancer detection. Currently, sweeping of the TRUS probe to build a 3D volume as part of the fusion process and the TRUS probe manipulation for needle guidance are both done manually. A motorized, joystick controlled, probe holder was custom fabricated that can potentially reduce inter-operator variability, provide standardization of needle placement, improve repeatability and uniformity of needle placement, which may have impacts upon the learning curve after clinical deployment of this emerging approach. Method: a 2DOF motorized probe holder was designed to provide translation and rotation of a triplane TRUS end firing probe for prostate biopsy. The probe holder was joystick controlled and can assist manipulation of the probe during needle insertion as well as in acquiring a smoother US 2D to 3D sweep in which the 3D US volume for fusion is built. A commercial MRI-US fusion platform was used. Three targets were specified on MR image of a commercial prostate phantom. After performing the registration, two operators performed targeting, once manually and once with the assistance of the motorized probe holder. They repeated these tasks 5 times resulting in a total of 30 targeting events. Time of completion and mechanical error i.e. distance of the target from the needle trajectory in the software user interface were measured. Repeatability in reaching a given target in a systematic and consistent way was measured using a scatter plot showing all targets in the US coordinate system. Pearson product-moment correlation coefficient (PPMCC) was used to demonstrate the probe steadiness during targeting. Results: the completion time was 25±17 sec, 25±24 sec, and 27±15 sec for free hand and 24±10 sec, 22.5±10 sec, and 37±10 sec for motorized insertion, for target 1, 2, and 3, respectively. The mechanical error was 0.75±0.4 mm, 0.45±0.4 mm, and 0.55±0.4 mm, for free hand approach while it was 1.0±0.57 mm, 0.45±0.4 mm, and 0.35±0.25 mm, for motorized approach, for target 1, 2, and 3, respectively. PPMCC remained almost at 1.0 for the motorized approach while having a variation between 0.9 and 1.0 for the free hand approach. Conclusions: motorized fusion guided prostate biopsy in a phantom study was feasible and non-inferior or comparable to the free hand manual approach in terms of accuracy and speed of targeting, while being superior in terms of repeatability and steadiness.

Paper Details

Date Published: 3 March 2017
PDF: 7 pages
Proc. SPIE 10135, Medical Imaging 2017: Image-Guided Procedures, Robotic Interventions, and Modeling, 101352B (3 March 2017); doi: 10.1117/12.2255550
Show Author Affiliations
Reza Seifabadi, National Institutes of Health (United States)
Sheng Xu, National Institutes of Health (United States)
Fereshteh Aalamifar, National Institutes of Health (United States)
Peter Pinto, National Institutes of Health (United States)
Bradford J. Wood, National Institutes of Health (United States)

Published in SPIE Proceedings Vol. 10135:
Medical Imaging 2017: Image-Guided Procedures, Robotic Interventions, and Modeling
Robert J. Webster III; Baowei Fei, Editor(s)

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