Preclinical PET/CT Imaging with C11 Radiotracers
for Cancer & Neurological Studies
Studies using PET imaging with carbon-11 (C-11) radiotracers have been made possible and easier at the BRIC Small Animal Imaging (SAI) facility. With the new small animal PET/CT system (SuperArgus, Sedecal Imaging) installed in the SAI facility, the core has developed a bed for C11 PET imaging of four mice simultaneously. Together with the development from the cyclotron facility, we can now provide C-11 PET imaging in mouse models with the following probes: 11C-AMT (tryptophan metabolism associated in immune-resistance), 11C-UCB-J (synaptic density), 11C-CB1 (cannabinoid receptor-1), 11C-raclopride (D2 dopamine receptor), and 11C-PIB (b-amyloid plaque).
Positron emission tomography (PET) imaging is the most sensitive imaging modality capable of detecting picomolar levels of concentration in the biological system. Many C-11 based PET probes have been developed to target various metabolic pathways or neuroreceptors in neurological disease. One of the major challenges for C11 PET imaging is its short half-life, 20.3 minutes. The fast decay of the C-11 radioisotope usually only allows imaging of one mouse with one dose production at the cost of a couple thousand dollars. Preclinical imaging with C-11 probes are thus cost-prohibitive, although technically feasible. This situation has been changed after the installation of the new PET/CT system obtained through NIH high-end instrumentation (HEI) S10 grant (S10-OD023611-01, PI: Zibo Li, PhD). The new system is equipped with large imaging bore size (120 mm) and dual layer design of crystals allowing for depth-of-interaction (DOI) correction with improved resolution across large field of view. The core further designed several multi-mice imaging beds and supporting accessories to provide anesthesia and vital sign monitoring for the multi-mice beds. Multi-mice imaging protocol for dynamic PET imaging has also been made available for research studies.
The new PET/CT along with the multi-mice imaging protocol has become a game changer for preclinical research with C-11 PET imaging (Figure-1). Several imaging studies have been initiated, such as 11C-UCB-J PET imaging to quantify changes of synaptic density in HIV induced neurological disorder in mouse models (PI: Sylvia Fitting, PhD, UNC Psychology), and 11C-raclopride PET imaging to assess responses of dopamine receptor in chronic opioid addiction in mice (PI: Lauren Slosky, Duke Cell Biology). We expect more PET molecular imaging with C-11 probes to be carried out in the SAI facility.
Figure 1. Small animal PET/CT imaging with C-11 probes