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Magnetic Resonance (MR)-compatible robot for prostate biopsy and its principal components. The x-, y-and zaxis correspond to the Axial, Coronal and Sagittal planes, respectively.
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... MIRIAM (Minimally Invasive Robotics In An MRI environment) system consists of a 5 DoF parallel robot to position and orientate the biopsy needle (Fig. 2) and a 4 DoF needle driver to insert, rotate and fire the biopsy needle. The needle driver inserts and rotates the needle using piezoelectric motors and fires the biopsy needle using pneumatic actuation. The needle driver is primarily designed for prostate biopsy, but it can be modified for other clinical applications, such as ...
Context 2
... 5 adjustable length rods, which allow for the translation of the needle guided in all three Cartesian axes and also two rotations. Each rod is actuated by a piezoelectric motor (HR2, Nanomotion, Yokneam, Israel). The robot provides maximum translational motion for the needle guide of 24 mm, 70 mm and 130 mm in x, y and z direction, respectively (Fig. 2). The robot also allows rotations of ±15° around the y-axis and rotations between 5° and -15° around the x-axis. This workspace guarantees that the robot is able to place the needle guide along the perineum and the needle can reach any point within the prostate even considering the variation in its size and location among individuals. ...
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Citations
... Needle driver Needle MIRIAM robot Fig. 2. The MIRIAM robot has five rods with adjustable lengths, which orient the needle driver that is able to insert, rotate and fire the biopsy needle [17]. ...
The use of magnetic resonance (MR) images for needle-based interventions offers several advantages over other types of imaging modalities (e.g., high tissue contrast and no radiation). However, MR-guided interventions face challenges related to electromagnetic compatibility of medical devices and real-time tracking of surgical instruments. This work presents a flexible needle steering system that combines an MR-compatible robot and a Fiber Bragg Grating (FBG)-based needle tip tracker. The MR images are used to localize obstacles and targets, while the FBG sensors provide strain measurements for online estimation of the needle tip position. A pre-operative planner defines the needle entry point and desired path, while a model predictive controller calculates the needle rotation during the insertion. To the best of the authors knowledge, this is the first work that fuses MR images and FBG-based tracking to steer a flexible needle in closed-loop inside the MR bore. The system is validated by steering a bevel-tipped flexible needle towards a physical target in gelatin phantoms and biological tissues. The needle reaches the target in all trials with an average targeting error of 2.76 mm. Disregarding the target displacement during the insertion, the average targeting error drops to 1.74 mm. The preliminary results demonstrate the feasibility of combining MR images and FBG-based needle tip tracking to steer a flexible needle in clinical procedures. In order to move towards to a clinically-relevant application, the design of a flexible Nitinol biopsy needle is also presented and evaluated by experiments in a prostate of a bull. The flexible needle presented a curvature 2.5 times larger than a conventional biopsy needle while maintaining the ability to collect tissue samples.
... Since electromagnetic motors are not MR safe or conditional, various alternative actuation methods have been investigated. While hydraulic [42,133], piezo [93,122], cable transmission [24], MRI-driven [40], air turbine [37], flexible fluidic actuators [30], direct-acting pneumatic actuators [135] and unidirectional pneumatic stepper motors [27] have been demonstrated, actuation by metalfree bidirectional pneumatic stepper motors has several important advantages. They are inherently MR safe, tolerant for small air leakages, can be controlled with a standard pneumatic valve manifold and allow for step-wise position control without need for a position feedback system. ...
... One of the key challenges in creating an MRI-compatible device is actuation. As electromagnetic motors are ruled out, many alternatives have been explored: hydraulic [133], piezo [93,122], cable transmission [24], MRI-driven [40], air turbine [37], flexible fluidic actuators [30], direct-acting pneumatic actuators [135], unidirectional pneumatic stepper motors [27], and especially bidirectional pneumatic stepper motors [26,46,49,60,109,110,113,118]. Bidirectional pneumatic stepper motors have several important advantages: control is relatively straightforward by using a standard pneumatic valve manifold, a position feedback system is not necessary (provided that steps are never skipped), small leakages are acceptable because the medium is atmospheric air, and motors are scalable by changing cylinder cross-sectional areas. ...
... Since electromagnetic motors are not MR safe or conditional, various alternative actuation methods have been investigated. While hydraulic [4], [5], piezo [6], [7], cable transmission [8], MRI-driven [9], air turbine [10], flexible fluidic actuators [11], direct-acting pneumatic actuators [12] and unidirectional pneumatic stepper motors [13] have been demonstrated, actuation by metal-free bidirectional pneumatic stepper motors has several important advantages. They are inherently MR safe, tolerant for small air leakages, can be controlled with a standard pneumatic valve manifold and allow for step-wise position control without need for a position feedback system. ...
In this paper, we show that magnetic resonance (MR) safe pneumatic stepper motors can be constructed using rapid prototyping techniques such as 3-D printing and laser-cutting. The designs are lightweight, metal-free, and fully customizable. Besides MR safe robotic systems, other potential applications include high-voltage switchgear and nuclear power plant systems, which also restrict electric actuation. In addition, it can be applied to other actuation systems, where pressurized air is available, and lightweight rapid prototypeable actuators are needed. Five pneumatically driven linear and rotational stepper motors have been developed with forces up to
$\text{330 N}$
, torques up to 3.7 N
$\cdot$
m, the stepping frequency up to 320 Hz, dimensions ranging from 25 to 80 mm, free of backlash, and power up to 26 W. All five motors are constructed from six 3-D printed parts and four seals, held together by nylon screws or clips. The described stepper motors outperform state-of-the-art plastic pneumatic stepper motor designs, both in specifications and in manufacturability.
... One of the key challenges in creating an MRI-compatible device is actuation. As electromagnetic motors are ruled out, many alternatives have been explored: hydraulic [3], piezo [4], [5], cable transmission [6], MRI-driven [7], air turbine [8], flexible fluidic actuators [9], direct-acting pneumatic actuators [10], unidirectional pneumatic stepper motors [11], and especially bidirectional pneumatic stepper motors [1], [2], [12]; c. Rotational motor and d. ...
Stormram 3 is a magnetic resonance imaging (MRI)-compatible robotic system that can perform MR-guided breast biopsies of suspicious lesions. The base of the robot measures 160 # 180 # 90 mm, and it is actuated by five custom pneumatic linear stepper motors, driven by a valve manifold outside the Faraday cage of the MRI scanner. All parts can be rapidly prototyped with three-dimensional (3-D) printing or laser cutting, making the design suitable for other applications, such as actuation in hazardous environments. Based on the choice of materials, the robot (with the exception of the needle) is inherently MR safe. Measurements show that the maximum force of the T-49 actuator is 70 N, at a pressure of 0.3 MPa. The Stormram 3 has an optimized repeatability that is lower than 0.5 mm, and it can achieve a positional accuracy on the order of 2 mm.
