Graphene based sensor system compatible with MRI and CT imaging
Magnetic resonance imaging (MRI) and computerised tomography (CT) scanners are medical devices that produce highly detailed images of human and animal anatomy. Stable and high-resolution MRI and CT images with minimum artefacts are obtained with adequate monitoring of body motion. To date, respiratory monitoring is achieved with respiratory balloons, however, limitations such as troublesome calibrations and often the need for repressurisation, make this a non-optimal technique. Piezoelectric sensors would have been considered more ideal for such monitoring if it wasn’t for the presence of metallic films in their structure, which have detrimental consequences for the images produced by both scanning techniques.
Researchers at the University of Oxford have developed a novel graphene-based piezoelectric sensor that is compatible with both MRI and CT imaging. Main advantages include radiolucency and minimal distortion to the magnetic field. In summary, the technology opens up new opportunities for graphene-based systems in MRI and CT sensing and diagnostics.
Body motion monitoring in MRI and CT imaging
Magnetic resonance imaging (MRI) and computerised tomography (CT) scanners are widely used to produce high-resolution images of human and animal anatomy. Due to the high magnetic fields and X-ray radiation used in MRI and CT scanning, respectively, there are significant limitations on the materials that may be placed inside the scanner.
Stable and high-resolution MRI and CT images with minimum artefacts can only be obtained when the effects of body motion are minimised. This is achieved by monitoring both cardiac and respiratory cycles and synchronising the image acquisition with this motion. Respiratory monitoring in small animal imaging is typically achieved with a respiratory balloon, a device that measures the change of air pressure within a capsule placed in contact with the abdomen. Limitations of this method include:
- The need for careful placement and calibration of the device
- Repressurisation and calibration if the animal is transferred between systems, a major drawback when changes in posture must be minimised
An alternative technique for respiratory monitoring uses piezoelectric sensors – devices which use a piezoelectric polymer to convert deflection into an electrical signal. Metallic thin films are deposited on both sides of the polymeric component for signal collection. Both calibration and setup are simple, and the device is insensitive to air pressure, however, these sensors have not found widespread use as the metallic films have detrimental consequences for the images produced by both scanning techniques.
Graphene-based piezoelectric sensors
Researchers at Oxford have tackled this limitation and developed a piezoelectric sensor compatible with MRI and CT imaging.
Metal has been replaced by thin layers of graphene, providing the following advantages:
- Minimal distortion to magnetic fields
- High in-plane conductivity
- High mechanical flexure and strain resilience
In addition, graphene technology has the potential to be used in a wide range of electronic components for MRI and CT imaging systems, thus creating many opportunities for graphene-based systems in MRI and CT sensing and diagnostics.
Oxford University Innovation Ltd. has filed a priority patent application on the technology and welcomes discussions with companies interested in licensing it for commercial development.
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