xMR
Research
Laboratories

MRI Systems Development

Gradient Coil Design & Construction

We have amassed experience in both design and manufacture of gradient coils for MRI systems, building approximately 10 prototypes in the last decade. Design methods, largely building on the PhD work of Chad Harris which used the Boundary Element Method are still being developed and are used extensively in house.

The use of the Boundary Element Method has allowed the design process to move away from the limitations imposed on magnet design in the past, such as a cylindrical coil or a centered target fieldregion, and instead calculate the optimum wire pattern to achieve a broad array of design goals. Importantly, manufacturing techniques and methods are taken into account at the design level, to reduce costs and time of the gradient construction, and to control the tolerances of the system and get a superior final result.

We continue to design and build gradient coils for multiple partners and will be pushing the envelope for electromagnetic and thermal performance as we implement new methods and ideas.

RF Systems Design

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Shim Coil

Shim Coil Development

Shimming magnetic fields, statically and dynamically is a necessary part of performing high quality magnetic resonance images. The Boundary Element Method is used to discover the wire patterns and to minimize the coupling between all other magnets in the system at the design stage, allowing us a high degree of flexibility. Shim coils are constructed with various manufacturing methods, depending upon the needs of the project and are constructed with a high tolerance.

Modeling & Simulation

By applying the principles of computational electromagnetism numerically, we can better understand the effects and potential dangers of medical device implants inside an MRI. This image demonstrates a calculation of human tissue heating around a sample passive medical device implant within an MRI system. These simulations, performed using Sim4Life, allow us to give feedback for the development of safer medical implants. There is also expertise in the group with COMSOL, CST, as well as in developing our own software to better understand the complex systems that matter for health care.

MR Application Development

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Medical Device Testing

Our lab specializes in performing MR safety tests in accordance with ISO 10974.

Thermal Imaging Camera

dB/dt Exposure

Rapidly changing gradient magnetic fields can induce eddy currents in metallic components of devices which can cause significant heating. Our lab has designed and built various dB/dt exposure systems for various device sizes and needs. We also use a combination of thermal imaging and fiber optic temperature probes to measure temperature changes throughout standard exposure levels.

Device Vibration

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Our lab is equipped to measure vibration in an MR scanner to micrometer precision using both a laser Doppler vibrometer and piezoelectric accelerometers. Device vibration is measured during exposure to varying gradient frequencies along a single axis. The device is placed in a high dB/dt location in the scanner to observe worst-case scenario.

When a conductive device is exposed to a changing gradient field inside a constant magnetic field, there is potential for vibration. We use miniature piezoelectric accelerometers and a laser Doppler vibrometer to measure device movement when exposed to worst-case scenarios in an MRI scanner. Typically, gradient pulse exposures consist of sinusoid or trapezoidal gradient pulses. To measure worst case scenarios, the devices are typically placed in a scanner location with a maximum dB/dt.

Torsion & Displacement

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RF Heating

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Image Distortion

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Ambient Electromagnetics

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Additive Manufacturing Utilisation

A Multi Axis Probe Housing

Specialized Phantom Clamps

Fittings for Mounting G10 Rods

Precise Equipment Mounting and Positioning

Fabricating Custom Water and Air Fittings

Form for Winding Induction Coils

Iterative Design Process

High Precision Multiple Probe Holder

Nylon Safety Caps for High Voltage Cables

Improving existing tools while using common connection fittings.

A Clip for Holding Titanium Rods.

Here at xMR Labs, we are consistantly improving our ability to utilize inovations in manufacturing technology to allow for the highest flexibility in our design processes.

To this end, we have incorporated the use of a variety of additive manufacturing techniques including FDM, SLA, and SLS, and are continuing to explore new methodologies to expand our ability to produce unique components for use in both gradient coil production and medical device testing.

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Recent Projects

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