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

Characterisation of Feline Leucocytes Labelled with 99mTc Stannous Fluoride Colloid

  • Dr Mohamed Abushhiwa, The University of Melbourne, Australia
  • Dr Nouria Salehi, Royal Melbourne Hospital, Australia
  • Dr Meir Lichtenstein, Royal Melbourne Hospital, Australia
  • Dr Robert Whitton, The University of Melbourne, Australia
  • Dr Charles Jennifer, The University of Melbourne, Australia
  • Dr Peter Finnin, The University of Melbourne, Australia
  • Dr Peter Lording, The University of Melbourne, Australia
  • Prof Bruce Parry, The University of Melbourne, Australia

    • Aims: 1) To investigate the ability of 99mTc-SnF colloid to label feline leucocytes in whole blood and meaure labelling retention; 2) to determine if labelling has any effect on leucocyte viability or phagocytic activity.

    Methods: Whole blood was collected from healthy cats and divided equally into unlabelled (control) and labelled samples. Leucocyte labeling with 99mTc-SnF colloid was carried out according to a standardised procedure (Radpharm Scientific, Australia). The labelling efficiency and leucocyte viability were determined.

    One mL aliquots of radiolabelled feline leucocytes at 2, 4, 6 and 7 hrs post-labelling were centrifuged and the radioactivity of the supernatant and cell pellet measured, and the labelling retention calculated.

    To assess phagocytic activity, control and labelled samples were layered onto 1077 Histopaque® and centrifuged to isolate leucocytes. Leucocytes were incubated with opsonised zymosan particles at 25°C for 3 hrs, one hundred-microlitter aliquots were cytocentrifuged and the smears stained with Giemsa stain. The leucocytes that had phagocytosed at least one zymosan particle were considered to be phagocyitc.

    Result: The labelling efficiency was 95.41 ± 1.71% and the viability for radiolabelled and control leukocytes were > 97%. The labelled leucocytes retained 93.6 ± 1.40% of the radioactivity for 7 hrs post-labelling. Labelled feline leucocytes had phagocytic activity of 90.0 ± 0.40% (control 91. 0 ± 0.70%).

    Conclusion: Feline leucocytes were efficiently radiolablled with 99mTc-SnF colloid and retained the majority of the radioactivity for at least 7 hrs post-labelling. The radiolabelling procedure did not adversely affect the viability or the phagocytic function of feline leucocytes.

    Conference Organiser - ICMS Pty Ltd