Graeme Clark Collection

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Start date: 2000 × End date: 2009 × Author: Cowan, Robert × Type: Conference Item × Subject: radiography ×

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    A comparative study of phase-contrast and conventional x-ray imaging in human temporal bone samples
    XU, JIN ; TYKOCINSKI, MICHAEL ; Saunders, E. ; Clark, Graeme M. ; Cowan, R. ( 2001)
    This study compared a new x-ray modality, phase-contrast radiography, with conventional radiography for imaging in human temporal bones and also investigated its potential application in the development of electrode arrays for advanced cochlear implants. Nucleus standard electrode arrays and peri-modiolar Contourn.4 electrode arrays were implanted into the cochleae of 10 human temporal bones. Both conventional and phase-contrast radiographs were taken of ~ach temporal bon~. The phase-contrast radiographs showed significant improvements over conventional radiographs in the detail of temporal bone images. These improvements included enhanced contrast at the edge of canal type features, inherent image magnification, higher spatial resolution, and ability to use detectors such as Imaging Plates. The results demonstrate that phase-contrast imaging can have important advantages in visualisation of anatomical details of both the inner ear structures and the microelectrode. It can provide a clearer definition of electrode location in relation to cochlear walls. This study demonstrates the feasibility of applying phase-contrast radiography to studies of the human temporal bone. However, its usefulness in the imaging of larger objects or perhaps even with patients in a clinical setting will require further investigation.
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    Application of advanced radiographic technology in cochlear implant research
    XU, JIN ; TYKOCINSKI, MICHAEL ; Saunders, E. ; Clark, Graeme M. ; Cowan, R. ( 2001)
    The effective development of peri-modiolar or other advanced electrode arrays for cochlear implants requires detailed analysis of the insertion procedure and electrode positioning in the cochlea. Routine x-ray techniques cannot provide sufficient detail to meet this need. A new micro-focus x-ray imaging system has been built for our research. The system consists of a x-ray tube with a sub 10-micron focal spot mounted below an adjustable work surface and an image intensifier placed approximately 100 cm above the x-ray aperture. A variety of intracochlear electrode arrays and human temporal bones were studied using this system. The micro-focus x-ray imaging system allows for micro-fluoroscopy to visualise the real time implantation procedure. It also enables capturing of images onto reusable phosphor imaging plates or films for subsequent viewing or analysis. Images are produced at up to 95 times magnification with superior resolution and enhanced contrast. This new radiographic technology plays an important role in development of safe and effective advanced intracochlear electrode arrays.
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    The role phase-contrast imagining in intra-cochlear electrode development
    Wilkins, S. ; Saudners, E. ; Clark, Graeme M. ; Cowan, R. ; XU, JIN ; Stevenson, A. W. ; Gao, D. ; Tykocinski, M. ; Cohen, L. ; Dahm, Markus ( 2000)
    In order to improve the design of intracochlear multichannel electrode arrays, it is fundamental that we have knowledge of the exact anatomical , position of the electrode within the scala of the cochlea. Currently, conventional skull radiography is still the mainstay of post-operative radiological assessment of electrode positioning. The present work investigates the use of phase-contrast radiography, a new x-ray modality, to provide improved imaging of the inner ear and the intracochlear electrode array in the human temporal bone (TB).