Molecular imaging
Animal imaging is the most important means of validating a radiopharmaceutical before clinical trials.
In lieu of primate imaging, rats and mice provide an intermediate surrogate. Imaging in vivo is the essential goal of radiopharmaceutical development. It is important for the development of both 'diagnostic' and therapeutic radiopharmaceuticals. For the diagnostic agent, the question is when can the lesion/tumour be imaged in the particular animal model. For the therapeutic agent, the question is how long does the radionuclide remain in the tumour. This information aids experimental design i.e., best sacrifices times for the experimental hypothesis.
The imaging of small animals (rats and mice) poses unique challenges. Particularly difficult to carefully characterise is radiopharmaceutical localization in the small structures of the brain or small tumours.
ANSTO's Radiopharmaceutical Research Institute is interested in examining both imaging and treatment agents with small animal cameras. With this it is necessary to consider the absorbed dose of the computerised topography (CT) scan. This may confound the effect of treatment and influence the localisation of the imaging agent. The CT dose may effect a treatment for tumoured animals and thereby reduce the localization of the imaging radiopharmaceutical. The dose would clearly perturb the effectiveness of a treatment agent.