Standards in clinical dual energy x-ray absorptiometry

  • Susan A. Steel

    Student thesis: Doctoral Thesis


    Dual Energy X-ray Absorptiometry (DXA) is a digital x-ray technique designed to quantify bone mineral density (BMD), primarily of the lumbar spine and hip, and hence to provide a measure of bone strength and propensity to fracture. The original technology was based on a pencil beam x-ray source but later systems use a fan beam. Additional functionality includes measurement of hand BMD and vertebral fracture assessment (VFA). Smaller devices have also been developed to measure BMD at peripheral sites in the body. As the numerical value of BMD resulting from this technique is used directly in diagnosis and decisions over patient clinical management, it is critical that the measurements are accurate and precise.

    The work presented in this thesis includes evaluation of the original pencil beam systems, later fan-beam technology, peripheral devices and additional functionality of DXA. This added to the knowledge of the technical capabilities and limitations of the technology providing an indication of precision, factors that may affect accuracy, radiation dose and machine comparison. Novel quality assurance phantoms were designed and constructed for assessing accuracy, precision and long-term stability of DXA-based hand and lateral morphometry techniques.

    Research was also conducted into factors associated with BMD, treatment compliance and effectiveness and the role of lateral vertebral assessment. This contributes to the growing body of knowledge on clinical risk factors, medical management and the appropriate use of DXA and VFA

    The thesis also includes the author's contribution to the national training scheme and development of guidelines which have helped raise standards of the technique nationally.

    These three areas of work contribute to ensuring the safe use of the new and developing technology and appropriate application within the clinical environment supported by highly trained operators and guidelines.
    Date of Award2009
    Original languageEnglish
    SupervisorPeter Plassmann (Supervisor) & Edward Ring (Supervisor)


    • Radiography, Medical
    • Digital techniques

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