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ADC and T2 response to radiotherapy in a human tumour xenograft model

  • Author / Creator
    Larocque, Matthew
  • A 9.4 T magnetic resonance imaging (MRI) system was used to evaluate the response of a human tumour xenograft model to radiation therapy. The apparent diffusion coefficient (ADC) and the transverse relaxation time (T2) of human glioblastoma multiforme (GBM) tumour xenografts in NIH-iii nude mice were measured before, and at multiple points after, treatment of the tumours with 200 kVp x-rays. The response was characterized as a function of a number of variables of interest in the clinical treatment of cancer with external beam radiation therapy. Mean tumour ADC and T2 responses after single fractions of radiation were investigated, with measurements being made until 14 days after treatment. Single fraction doses ranged from 50 cGy to 800 cGy. Fractionated treatments were used to deliver 800 cGy in two or three fractions with fraction spacings of 24 or 72 hours. The role of hypoxia on ADC and T2 response was investigated by using an externally-applied, suture-based ligature to induce a state of reduced oxygenation in tumours during treatment, after which ADC and T2 were measured using serial MRI. Finally, tumours were dissected in order to provide insight into possible pathophysiological mechanisms explaining the observed responses. Tissue sections were prepared and reviewed by a pathologist. This work adds to the body of literature describing tumour ADC and T2 response to anticancer therapy, and adds to the understanding of ADC and T2 response to radiation therapy in particular. This works supports that of others suggesting the use of ADC and T2 as potential biomarkers for tumour response to treatment.

  • Subjects / Keywords
  • Graduation date
    2010-11
  • Type of Item
    Thesis
  • Degree
    Doctor of Philosophy
  • DOI
    https://doi.org/10.7939/R3831R
  • License
    This thesis is made available by the University of Alberta Libraries with permission of the copyright owner solely for non-commercial purposes. This thesis, or any portion thereof, may not otherwise be copied or reproduced without the written consent of the copyright owner, except to the extent permitted by Canadian copyright law.
  • Language
    English
  • Institution
    University of Alberta
  • Degree level
    Doctoral
  • Department
    • Department of Physics
  • Supervisor / co-supervisor and their department(s)
    • Fallone, B. Gino (Physics and Oncology)
    • Syme, Alasdair (Oncology)
  • Examining committee members and their departments
    • Marchand, Richard (Physics)
    • Schreiner, L. John (Physics and Oncology, Queen's University)
    • Rathee, Satyapal (Oncology)
    • Beamish, John (Physics)
    • Riauka, Terence (Oncology)