Abstract for presentation at 38th Annual Scientific Meeting of the Australian and New Zealand Society of Nuclear Medicine 2008

Apoptosis Detection Using 99mTc-Hynic-Annexin V in a Thymoma Mouse Model

  • Miss Effie Wong, Department of Nuclear Medicine, The St. George Hospital, Australia
  • A/Prof Vijay Kumar, Department of Nuclear Medicine, Clinical Ultrasound and P.E.T., Westmead Hospital, Australia
  • Prof Robert Howman-Giles, Department of Nuclear Medicine, The Children's Hospital at Westmead, Australia
  • A/Prof Jean-Luc van der Heyden, Technology and Medical Office, GE Healthcare, United States

    • Objective:
    To assess the potential of 99mTc-Hynic-Annexin V, for the in vivo imaging of apoptosis after chemotherapy and radiotherapy in nude mice bearing thymoma tumours. Several studies have reported good correlation of this agent with therapy-induced apoptosis. However none have reported on the comparisons of two modes of cancer treatment.

    Methods:
    Mice bearing thymoma tumours were divided into three cohorts: controls, chemotherapy-treated and radiotherapy-treated. 99mTc-Hynic-Annexin V was administered intravenously to tumour bearing mice, before (control group) and after therapy (chemotherapy and radiotherapy groups) and imaged at 1 and 4 hours post-injection. The animals were then sacrificed and their major organs and tissues, including the tumour, were harvested. Histopathology was performed on intact tumour and post-therapy tumour sections.

    Results:
    The percentage injected dose per gram tissue (%ID/g) of harvested tissues was calculated to assess biodistribution of the agent. The data demonstrated the physiological localisation of the agent in the kidneys, liver and urine. Uptake of the agent in the tumour increased significantly in the tumour after treatment with therapy compared to the control tumour. Tumour to muscle and tumour to blood ratios were significantly higher in treated tumours than the control tumour. Further analyses demonstrated a positive correlation between the number of apoptotic cells detected on histopathological tests and the percentage localisation of 99mTc-Hynic-Annexin V in tumours.

    Conclusion:
    The results indicate 99mTc-Hynic-Annexin V may be an ideal agent for the imaging of apoptosis in assessing the response to treatment in a thymoma tumour-bearing mouse model.

    Conference Organiser - ICMS Pty Ltd