Method for characterising a mechanical property of a material
Inventors
Mclaughlin, Robert Ainsley • Kennedy, Kelsey Marie • Kennedy, Brendan Francis • Sampson, David Douglas
Assignees
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Publication Number
US-11246487-B2
Publication Date
2022-02-15
Expiration Date
Abstract
A method for characterising a mechanical property of a material. The method comprises the steps of providing the material having a deformable portion and providing a device having an optical element that is arranged to detect electromagnetic radiation.
Core Innovation
The invention provides an optical elastography method and device for characterising mechanical properties of a deformable biological tissue by deforming the tissue with a device insertion portion and using optical fibre transmission and detection of backscattered electromagnetic radiation. The device emits electromagnetic radiation into the deformable portion while the deformable portion is being deformed by movement of the insertion portion, and receives electromagnetic radiation backscattered from a location within the deformable portion. The detected electromagnetic radiation is processed to derive information indicative of tissue deformation.
From the derived deformation information, the invention identifies a relative displacement of the biological tissue at each of a plurality of distances from a position of the tip of the insertion portion. The relative displacement is associated with a mechanical property of the biological tissue. The invention further identifies a location of an interface between different biological tissue types based on differences in the relative displacement at the different distances from the tip position, including an abrupt slope change in a displacement versus distance relationship.
The device includes an insertion portion with a tip having a surface comprising a coating arranged to decrease friction between the insertion portion and the deformable portion compared with friction without the coating. In the device, an optical fibre portion is configured to transmit electromagnetic radiation from the device into the deformable portion and to receive electromagnetic radiation backscattered from a location within the deformable portion during deformation by insertion portion movement, with the optical fibre connected to an optical processing system for emission and detection.
Claims Coverage
The document includes two independent claims that cover a method and a device for analysing deformable biological tissue. Across these independent claims, the inventive features include optical fibre-based emission and detection during tissue deformation, deriving displacement versus distance from the insertion tip, associating displacement with a mechanical property, and identifying an interface between different biological tissue types based on differences in the derived displacement profile.
Coated low-friction insertion tip with optical fibre emission and reception
An insertion portion arranged for insertion into the deformable portion, having a tip with a surface comprising a coating arranged to decrease friction, together with an optical fibre portion positioned to transmit electromagnetic radiation into the deformable portion and receive electromagnetic radiation backscattered from a location within the deformable portion during deformation while the insertion portion is moved.
Displacement-vs-distance derived from backscattered electromagnetic radiation during deformation
Deriving information indicative of deformation of the deformable portion resulting from moving the insertion portion within the biological tissue, and identifying a relative displacement of the biological tissue at each of a plurality of distances from the position of the tip based on processing of the detected backscattered electromagnetic radiation.
Interface localization between different biological tissue types from displacement differences
Identifying a location of an interface between different biological tissue types based on differences in the relative displacement at the different distances from the position of the tip.
Electronic processor for displacement relative to tip and interface identification
An electronic processor configured to identify displacement of the biological tissue relative to a position of the tip using information derived from the detected backscattered electromagnetic radiation, where the displacement is associated with the mechanical property, and to identify an interface between different biological tissue types based on differences in the relative displacement at the different distances from the tip position.
Overall, the independent claims are directed to an optical elastography system that uses a coated low-friction insertion tip and an optical fibre to emit and receive backscattered electromagnetic radiation during deformation, processes the backscattered signals to derive relative displacement at multiple distances from the tip associated with a mechanical property, and uses differences in the displacement profile to identify an interface between different biological tissue types.
Stated Advantages
Real-time tumour boundary/interface localization and potential clinical guidance during surgery.
In vivo characterization of mechanical properties of biological tissue (elasticity/viscosity/viscoelasticity).
Ability to identify interfaces between different tissue or tissue-layer types based on changes in strain or slope.
Documented Applications
Application to biological tissue characterization in vivo, including detecting a tumour boundary/interface and providing clinical guidance during surgery.
Characterisation of layered tissue interfaces using silicone phantoms, human breast tissue, and layered tracheal tissue.
Viscoelasticity measurement using relaxation after a stop.
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