Mechanical characterisation of soft biological tissue by using surface acoustic waves

  • Sinan Li

    Student thesis: Master's ThesisMaster of Science


    Mechanical properties are important parameters in assessing physiologic conditions of biologic tissue for medical diagnosis or disease progression tracking. Surface acoustic waves (SAWs) have been preliminarily used for the characterisation of tissue mechanical properties and it is increasingly becoming a topic of research interest as SAWs can provide more localised information in the tissue near-surface region which is particular advantaged for the clinical diagnosis of skin malignant diseases, such as carcinoma cutaneum and scleroderma. This dissertation further exploited the use of surface acoustic waves in the tissue mechanical characterisation, it takes a novelty approach in applying SAW for a precise mechanical characterisation of layered soft tissue, in terms of both stiffness characterisation and thickness evaluation. There are the two main contributions reported and discussed in this dissertation:
    Firstly, from a validated numeric analysis of acoustic wave propagation, SAWs have been found to be highly sensitive to the elasticity variation distributed along the surface of tissue sample; an immediate, dramatic change of both attenuation and velocity of surface acoustic waves were observed at the tissue elasticity boundaries. These results can be used to get a rapid locating and quantification of the abnormalities along the tissue superficial layer. Secondly, investigation of using SAWs was also reported for evaluation of vertical elasticity variations at depth of tissue by analysing the phase velocity and taking consideration of the surface wave penetration attributes. Using an advanced method for generating a robust surface wave signal with eliminated perturbations, SAWs found to be not only capable to do an accurate quantification of the stiffness in a layered structure, but also can provide reliable characterisation of the thickness of the superficial layer. Results were obtained and calibrated on tissue mimicking phantoms and further validated on ex-vivo biologic tissues.
    Date of Award2011
    Original languageEnglish
    SupervisorZhihong Huang (Supervisor)


    • Surface acoustic waves
    • Tissue mechanical property
    • Elasticity

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