Reza Seifabadi

Publications (11) View all

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  Available from: Reza Seifabadi

  Conference Proceeding: Design of a Decoupled MRI-compatible Force Sensor using Fiber Bragg Grating Sensors for Robot-assisted Prostate Interventions

  R. Monfaredi, R. Seifabadi, G. Fichtinger, I. Iordachita
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  ABSTRACT: During prostate needle insertion, the gland rotates and displaces resulting in needle placement inaccuracy. To compensate for this error, we proposed master-slave needle steering under real-time MRI in a previous study. For MRI-compatibility and accurate motion control, the master (and the slave) robot uses piezo actuators. These actuators however, are non-backdrivable. To cope with this issue, force sensor is required. Force sensor is also required at the slave side to reflect the insertion force to clinician’s hand through the master robot. Currently, there is no MRI-compatible force sensor commercially available. In order to generate a combination of linear and rotary motions for needle steering, this study is seeking to develop a MRI-compatible 2 Degrees of Freedom (DOF) force/torque sensor. Fiber Brag Grating (FBG) strain measuring sensors which are proven to be MRI-compatible are used. The active element is made of phosphor-bronze and other parts are made of brass. The force and torque measurements are designed to be entirely decoupled. The sensor measures -20 to 20 N axial force with 0.1 N resolution, and -200 to 200 Nmm axial torque with 1 Nmm resolution. Analytical and Finite Element (FE) analyses are performed to ensure the strains are within the measurable range of the FBG sensors. The sensor is designed to be compact (diameter =15 mm, height =20 mm) and easy to handle and install. The proposed sensor is fabricated and calibrated using a commercial force/torque sensor.
  SPIE Medical Imaging, Orlando, FL; 02/2013
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  Available from: Reza Seifabadi

  Conference Proceeding: Design of a Teleoperated needle steering system for MRI-guided prostate interventions

  R. Seifabadi, I. Iordachita, G. Fichtinger
  IEEE International Conference on Biomedical Robotics and Biomechatronics (BioRob 2012); 06/2012
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  Article: Preclinical evaluation of MRI-compatible pneumatic robot for angulated needle placement in prostate interventions

  J. Tokuda, S.E Song, G. Fischer, I. Iordachita, R. Seifabadi, BJ. Cho, G. Fichtinger, C. M. Tempany, N. Hata
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  ABSTRACT: Purpose. To support transperineal prostate biopsies in a closed-bore magnetic resonance imaging (MRI) scanner, we developed a small profile MRI-compatible pneumatic needle placement robot that can angulate a needle insertion path into a large accessible target volume. We performed a preclinical evaluation of the robot’s targeting accuracy with angulated needle insertion in a 3 Tesla clinical MRI. Methods. Angulation of the needle insertion path is achieved by a four degrees-of-freedom (4-DOF) mechanism with two parallel triangular structures. The robot is integrated with navigation software that allows an operator to plan angulated needle insertion by selecting a target and an entry point. The targeting error was evaluated while the angle between the needle insertion path and the static magnetic field was between -5.7° and 5.7° horizontally and between -5.7° and 4.3° vertically in the MRI scanner after sterilizing and draping the device. Results. The needle placement robot successfully positioned the needle with angulated insertion as specified on the navigation software. The overall targeting error was 0.8 ± 0.5 mm along the horizontal axis and 0.8 ± 0.8 mm along the vertical axis. The two-dimensional root-mean-square targeting error on the axial slices as containing the targets was 1.4 mm. Conclusions. Our preclinical evaluation demonstrated that the MRI-compatible pneumatic needle placement robot with the 4-DOF parallel kinematic structure with the capability to angulate the needle insertion path provides sufficient targeting accuracy for clinical MRI-guided prostate interventions
  International Journal of Computer Assisted Radiology and Surgery 05/2012; · 1.48 Impact Factor
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  Conference Proceeding: Position coordination of a linear teleoperation system with constant time delay

  K. Razi, M. Yazdanpanah, S.S. Ghidary, H.H. Najafabadi, M. Zareinejad, R. Seifabadi, S.M. Rezaei
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  ABSTRACT: In this paper we present a linear time invariant controller for bilateral teleoperation of a pair of N-DOF linear robotic systems under constant time delay. Our framework uses position and velocity signals to achieve position tracking in free motion. It also uses force feedback for compensating the human/environment disturbances to achieve position coordination in contact tasks. In passifying position and velocity feedback terms, for simplicity reasons there is no need to consider the dynamics of the robotic systems as long as they satisfy Euler-Lagrangian dynamic system equation. However when the force feedback is applied, we have to consider the dynamics of the robot in controller design. We do passivity analysis in the frequency domain by using Parseval's identity. Simulation has been performed to illustrate the proposed algorithm and to clarify some points in the design procedure.
  Intelligent Robots and Systems, 2007. IROS 2007. IEEE/RSJ International Conference on; 12/2007
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  Article: Robotic system for MRI-guided prostate biopsy: feasibility of teleoperated needle insertion and ex vivo phantom study.

  Reza Seifabadi, Sang-Eun Song, Axel Krieger, Nathan Bongjoon Cho, Junichi Tokuda, Gabor Fichtinger, Iulian Iordachita
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  ABSTRACT: Magnetic Resonance Imaging (MRI) combined with robotic assistance has the potential to improve on clinical outcomes of biopsy and local treatment of prostate cancer. We report the workspace optimization and phantom evaluation of a five Degree of Freedom (DOF) parallel pneumatically actuated modular robot for MRI-guided prostate biopsy. To shorten procedure time and consequently increase patient comfort and system accuracy, a prototype of a MRI-compatible master-slave needle driver module using piezo motors was also added to the base robot. Variable size workspace was achieved using appropriate link length, compared with the previous design. The 5-DOF targeting accuracy demonstrated an average error of 2.5 mm (STD = 1.37 mm) in a realistic phantom inside a 3T magnet with a bevel-tip 18G needle. The average position tracking error of the master-slave needle driver was always below 0.1 mm. Phantom experiments showed sufficient accuracy for manual prostate biopsy. Also, the implementation of teleoperated needle insertion was feasible and accurate. These two together suggest the feasibility of accurate fully actuated needle placement into prostate while keeping the clinician supervision over the task.
  International Journal of Computer Assisted Radiology and Surgery 06/2011; 7(2):181-90. · 1.48 Impact Factor