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

The Use of Multiple Pinhole SPECT to Measure the Heterogeneity of Small Animal Tumour Models

  • Mr Peter Kench, Brain & Mind Research Institute, The University of Sydney, Australia
  • Dr Marie-Claude Gregoire, Radiopharmaceutical Research Institute, ANSTO, Australia
  • Dr Mitchell Quinlivan, Radiopharmaceutical Research Institute, ANSTO, Australia
  • Dr Jianyu Lin, Brain & Mind Research Institute, The University of Sydney, Australia
  • Filomena Mattner, Radiopharmaceutical Research Institute, ANSTO, Australia
  • Dr Andrew Katsifis, Radiopharmaceutical Research Institute, ANSTO, Australia
  • Dr Steven Meikle, Brain & Mind Research Institute, The University of Sydney, Australia

    • Objective: Biodistribution studies play an important role in the pre-clinical evaluation of new and novel tumour radiopharmaceuticals (RP). Small animal SPECT imaging can provide additional information on the heterogeneity of the RP distribution within tumour tissue. A small animal SPECT camera must have high spatial resolution and sensitivity due to the small size of the tumour tissue and the small amount of RP activity. Spatial resolution can be improved through pinhole collimation due to its magnification properties. The use of multiple pinhole collimation can improve the camera’s sensitivity.

    Method: A dual detector X-SPECT camera, Gamma Medica Ideas, was fitted with a locally designed multiple pinhole collimator. A SPECT acquisition was performed on an ex-vivo A375 mouse prostate tumour labeled with a Iodine-123 PBR ligand. One detector was fitted with a single pinhole collimator with an aperture of 1.5 mm. The second detector was fitted with a dual pinhole collimator with apertures of 1 mm.

    Results: Similar detector sensitivity was measured with the single (1.5 mm aperture) and dual (2 x 1 mm aperture) pinhole collimators. Improved spatial resolution and contrast recovery was observed in the dual compared to the single pinhole SPECT reconstruction.

    Conclusion: It is possible to observe millimeteric heterogeneity within ex-vivo tumour tissue using multiple pinhole small animal SPECT. Further work will aim to improve the multiple pinhole design and the SPECT reconstruction algorithm to achieve sub-millimetric spatial resolution.

    Conference Organiser - ICMS Pty Ltd