MR-Safe Pneumatic Rotation Stepping Actuator

2012 ◽  
Vol 24 (5) ◽  
pp. 820-827 ◽  
Author(s):  
Hiroyuki Sajima ◽  
◽  
Hiroki Kamiuchi ◽  
Kenta Kuwana ◽  
Takeyoshi Dohi ◽  
...  
Keyword(s):  
Surgical Navigation ◽  
Safety Evaluation ◽  
Surgical Instruments ◽  
Resonance Imaging ◽  
Surgical Robots ◽  
Maximum Torque ◽  
Pneumatic Actuators ◽  
Magnetic Resonance Imaging Mri ◽  
Mr Safe ◽  
Direct Acting

Magnetic Resonance Imaging (MRI) is widely used not only for diagnosis but also for surgical navigation, etc. Surgeons and surgery-support systems can conduct surgeries less invasively because they derive accurate positional relationships between surgical instruments and anatomical regions of interest from preoperative or intraoperative MRI images. Many surgical robots intended for use within MRI gantries have been developed. Some of them use pneumatic actuators that are difficult to control accurately or that have many components, however, causing high fabrication cost, low durability and low sterilizability. To solve these problems, we have developed a φ30-mm pneumatic rotation stepping actuator. The actuator consists of three Direct Acting gears (D.A. gears) and a Rotation gear (R gear). When all of the D.A. gears are pushed sequentially up by compressed air, the R gear rotates because it engages all of them. In a fundamental performance experiment, the maximum angular error was 2.1° and maximum torque was approximately 150 mNm using 0.6 MPaG. Additionally, in an MR safety evaluation, the actuator was not found to cause any distortion or artifacts in MRI images. The actuator can therefore be applied to MR-safe positioning or puncturing robots.

scholarly journals Demonstration and Experimental Validation of Plastic-Encased Resonant Ultrasonic Piezoelectric Actuator for Magnetic Resonance Imaging-Guided Surgical Robots

2019 ◽  
Vol 3 (1) ◽  
Author(s):  
Paulo A. W. G. Carvalho ◽  
Christopher J. Nycz ◽  
Katie Y. Gandomi ◽  
Gregory S. Fischer
Keyword(s):  
Magnetic Resonance Imaging ◽  
Magnetic Resonance ◽  
Signal To Noise Ratio ◽  
Surgical Instruments ◽  
Resonance Imaging ◽  
Surgical Robots ◽  
Additional Signal ◽  
High Metal Content ◽  
Piezoelectric Elements ◽  
Magnetic Resonance Imaging Mri

Abstract Intra-operative medical imaging based on magnetic resonance imaging (MRI) coupled with robotic manipulation of surgical instruments enables precise feedback-driven procedures. Electrically powered nonferromagnetic motors based on piezoelectric elements have shown to be well suited for MRI robots. However, even avoiding ferrous materials, the high metal content on commercially available motors still cause distortions to the magnetic fields. We construct semicustom piezoelectric actuators wherein the quantity of conductive material is minimized and demonstrate that the distortion issues can be partly addressed through substituting several of these components for plastic equivalents, while maintaining motor functionality. Distortion was measured by assessing the root-mean-squared (RMS) change in position of 49 centroid points in a 12.5 mm square grid of a gelatin-filled phantom. The metal motor caused a distortion of up to 4.91 mm versus 0.55 mm for the plastic motor. An additional signal-to-noise-ratio (SNR) drop between motor off and motor spinning of approximately 20% was not statistically different for metal versus plastic (p = 0.36).

scholarly journals Demonstration and Experimental Validation of Plastic-Encased Resonant Ultrasonic Piezoelectric Actuator for MRI-Guided Surgical Robots

2018 ◽  
Author(s):  
Paulo A. W. G. Carvalho ◽  
Christopher J. Nycz ◽  
Katie Y. Gandomi ◽  
Gregory S. Fischer
Keyword(s):  
Metal Content ◽  
Experimental Validation ◽  
Surgical Instruments ◽  
Robotic Manipulation ◽  
Resonance Imaging ◽  
Surgical Robots ◽  
High Metal Content ◽  
Piezoelectric Elements ◽  
High Metal ◽  
Magnetic Resonance Imaging Mri

Intra-operative medical imaging based on magnetic resonance imaging (MRI) coupled with robotic manipulation of surgical instruments enables precise feedback-driven procedures. Electrically powered non-ferromagnetic motors based on piezoelectric elements have shown to be well suited for MRI robots. However, even avoiding ferrous materials, the high metal content on commercially available motors still cause distortions to the magnetic fields. We construct semi-custom piezoelectric actuators wherein the quantity of conductive material is minimized and demonstrate that the distortion issues can be partly addressed through substituting several of these components for plastic equivalents, while maintaining motor functionality. Distortion was measured by assessing the RMS change in position of 49 centroid points in a 12.5mm square grid of a gelatin-filled phantom. The metal motor caused a distortion of up to 4.91mm versus 0.55mm for the plastic motor. An additional SNR drop between motor off and motor spinning of approximately 20% was not statistically different for metal versus plastic (p = 0.36).

Enhanced Anatomic Visualization with Ultrasound-Assisted Intracranial Image-Guidance in Neurosurgery

2002 ◽  
Vol 1 (3) ◽  
pp. 181-185 ◽  
Author(s):  
Alexandre M. N. Marinho ◽  
Manali Barua ◽  
John Haller ◽  
Timothy C. Ryken
Keyword(s):  
Image Guidance ◽  
Surgical Navigation ◽  
Intraoperative Ultrasound ◽  
Ultrasound Images ◽  
Brain Shift ◽  
Resonance Imaging ◽  
Surgical Navigation System ◽  
Ultrasound Assisted ◽  
Magnetic Resonance Imaging Mri ◽  
Ultrasound Scanner

Anatomical comparisons between ultrasound images and magnetic resonance imaging (MRI)/computed tomography (CT) preoperative images were performed in four ultrasound-assisted image-guided intracranial surgeries. An ultrasound scanner connected to a surgical navigation system allowed the neurosurgeon to acquire useful views from that integration, offering an improved method for visualization. This surgical navigation device and associated ultrasound provides real-time brain shift correction. The accuracy of navigation depends on the identification of the anatomic structures. Despite some limitations of the ultrasound images, the ability to compare preoperative MRI and intraoperative ultrasound proved useful to the surgeon.

scholarly journals A quick guide to safety and compatibility of passive implants and devices in an MR environment

2004 ◽  
Vol 8 (2) ◽  
pp. 6 ◽  
Author(s):  
D.J. Kotze ◽  
C. De Vries
Keyword(s):  
Resonance Imaging ◽  
Electrical Currents ◽  
Additional Risk ◽  
Metal Implants ◽  
Passive Devices ◽  
Number Of Patients ◽  
Magnetic Resonance Imaging Mri ◽  
Mr Safe ◽  
Intended Use

An increasing number of patients with metal implants are being referred for magnetic resonance imaging (MRI) investigations. Implants and devices may be divided into two groups, namely active and passive. This article will focus on passive devices. A device is MR-safe when it is used in the MR environment, but presents no additional risk to the patient or other individuals, although the quality of diagnostic information may be affected. MR procedures may be contraindicated due to various interactions between the MR environment and medical devices, which include torque, translational force, heating, induced electrical currents, magnetic field interactions, artefacts, and misrepresentation. Therefore, before deciding whether any object is MRsafe/ compatible, the intended use and the possible retaining mechanisms must be considered.

Top-Ten Tips for Imaging the Brachial Plexus with Ultrasound and MRI

2019 ◽  
Vol 23 (04) ◽  
pp. 405-418 ◽  
Author(s):  
James F. Griffith ◽  
Radhesh Krishna Lalam
Keyword(s):  
Magnetic Resonance Imaging ◽  
Magnetic Resonance ◽  
Brachial Plexus ◽  
Muscle Denervation ◽  
Resonance Imaging ◽  
Neural Injury ◽  
Clinical Indications ◽  
Magnetic Resonance Imaging Mri ◽  
High Level ◽  
Extensive Involvement

AbstractWhen it comes to examining the brachial plexus, ultrasound (US) and magnetic resonance imaging (MRI) are complementary investigations. US is well placed for screening most extraforaminal pathologies, whereas MRI is more sensitive and accurate for specific clinical indications. For example, MRI is probably the preferred technique for assessment of trauma because it enables a thorough evaluation of both the intraspinal and extraspinal elements, although US can depict extraforaminal neural injury with a high level of accuracy. Conversely, US is probably the preferred technique for examination of neurologic amyotrophy because a more extensive involvement beyond the brachial plexus is the norm, although MRI is more sensitive than US for evaluating muscle denervation associated with this entity. With this synergy in mind, this review highlights the tips for examining the brachial plexus with US and MRI.

Use of Magnetic Resonance Imaging (MRI) to Determine the 3D Geometry in the Human Rectum

Endoscopy ◽  
2004 ◽  
Vol 36 (10) ◽  
Author(s):  
BP McMahon ◽  
JB Frøkjær ◽  
A Bergmann ◽  
DH Liao ◽  
E Steffensen ◽  
...  
Keyword(s):  
Magnetic Resonance Imaging ◽  
Magnetic Resonance ◽  
Resonance Imaging ◽  
3D Geometry ◽  
Human Rectum ◽  
Magnetic Resonance Imaging Mri
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