Session: 06-10-01: Robotics, Rehabilitation

Paper Number: 145176

145176 - Towards Design and Preliminary Evaluation of an Mri-Compatible Teleoperative Robot for Needle-Based Prostate Interventions – Enabling Needle Bending via a Tendon-Driven Notched Needle 

Prostate cancer is the second most prevalent cancer type among men. According to the American Cancer Society, about 1 in 8 men will be diagnosed with prostate cancer in their lifetime. Recently, advancements in needle-based prostate interventions for diagnoses and treatments such as biopsy and brachytherapy have been making large strides.

 

In particular, needle insertions under magnetic resonance imaging (MRI) guidance have gained significant tractions. MRI provides excellent imaging feedback to track and visualize the needle inside the body that is valuable for accurate needle placement. Recent research has been largely focused on developing MRI-compatible teleoperative robotic systems and integration with MRI systems.

 

On the other hand, active needles have shown potential to improve needle guidance along curved trajectories towards target(s). Needle steering in curved trajectories is of special interest in needle-based prostate interventions due to possible presence of obstructing anatomies (e.g., pubic arch interference in some patients), that make needle insertions in straights line towards the target(s) challenging or impossible.

 

Therefore, teleoperative robotic needle insertion systems when integrated with MRI for improved visualization and with active needles for improved trajectory tracking could potentially improve clinical outcomes.

 

This work introduces, for the first time, an MRI-compatible (slave) robot for MRI-guided tendon-driven active needle insertions. The robot is designed, fabricated, and assembled with MRI-compatible materials, sensors, and actuators to enable needle insertion and needle bending while inside the MRI bore.

 

The minimum required range of motion appropriate for prostate interventions specifies an axial, bilateral (two directions in horizontal plane), and vertical movements of 70, 40, and 750mm, respectively to be realized by a three degrees of freedom mechanism. Larger displacements are desired. The mechanism allows for manual preoperational positioning, thereby only translational displacements shall be required to reach any point within its functional range.

 

The robot is designed with three main sections of (i) manual positioning stage, (i) robotically controlled Scott-Russell scissor mechanism, and (iii) needle manipulation system.

 

The manual positioning stage (fabricated from acrylic using a waterjet cutting machine and aluminum hardware) allows user to manually align the robot in the horizontal plane. The Scott-Russell mechanism is used to control the vertical positioning of the needle. It is fabricated through 3D printing and aluminum hardware, actuated by one rotary piezo motor (from PiezoMotion). The needle manipulation system is responsible for tendon displacement control of the active needle to produce bending via two rotary piezo motors, as well as needle insertion and stylet tray manipulation using two linear piezo motors (LT2020C-101E1A00, Stall force 20N, 8mm stroke, 101mm drive rod from PiezoMotor).

 

In the first set of experiments, the range of motion of the robot is evaluated. Motors are actuated in open-loop control to the limits of the robot design. The displacements in all translational directions are measured. The measurements are then compared with simulation results from the CAD assembly.

 

In the second set of experiments, teleoperative control is established and evaluated. A computer script interface with a handheld joystick controller (master device) and with the motors installed in the robot. The robot is actuated through user-input into the joystick controller to reach a series of targets. Efficacy of teleoperation in this robot design is evaluated based on the required range of motion. The range of motion using teleoperation is compared to the maximum range of motion measured in the first set of experiments.

 

In summary this work presented an MRI-compatible robot with three degrees of freedom, 270mm of displacement along the insertion axis, 90mm bilateral displacement in the horizontal plane for alignment, and 750mm vertical displacement (exceeding design requirements) to enable MRI-guided active needle insertions in prostate. Teleoperation is shown to be effective at controlling the robot’s position, as well as needle actuation.

Presenting Author: Bardia Konh University of Hawaii at Manoa

Presenting Author Biography: Bardia Konh is an Associate Professor of Mechanical Engineering, and the founder and director of the Advanced Manufacturing and Medical Instruments (AMMI) Laboratory at University of Hawaii at Manoa (UHM). His research focuses on various areas including medical robotics, meso-scale flexible robots, sensing and actuation, system architecture, ultrasound needle tracking, image-guided interventions, and control.

Authors:

Blayton Padasdao University of Hawaii at Manoa
Rex Imanaka University of Hawaii at Manoa
Bardia Konh University of Hawaii at Manoa