We offer in vivo micro-PET study design, execution, and data analysis across a broad spectrum of disease models and analytic techniques. Our imaging experts and disease area experts design and execute PET studies for maximal clinical relevance, statistical power, and throughput. Our PET studies are performed using a Siemens Inveon scanner.
Positron emission tomography (PET) is a nuclear medicine imaging technique that generates 3D images of an injected PET radioisotope-labeled molecule in the body. Radiotracer distribution is detected via emitted gamma photons resulting from positron-electron annihilation. PET imaging in the preclinical setting (micro-PET) is increasingly being used in drug discovery to study disease biology and biodistribution and kinetics of biologic molecules.
In Vivo Biodistribution Imaging With Long-lived PET Isotopes
A variety of PET isotopes can be used in translational studies to assess test molecule biodistribution, targeting, kinetics, and clearance. We are licensed to use a broad array of PET isotopes (see table below) to assess biodistribution of molecules including:
- Antibody fragments
The isotopes we can use cover a variety of labeling methods, half-lives, and imaging properties that can be tailored to specific needs. These include:
|PET Isotope||Half Life||Common Applications|
|Fluorine-18 [18F]||1.8 hours||FLT, FDG|
|Copper-64 [64CU]||12.7 hours||Short-term tacking of small molecules and peptides; imaging of disease state and efficacy using targeted biologics|
|Yttrium-86 [86Y]||14.7 hours||Analog of [90Y] radiotherapy isotope that can be used for imaging studies|
|Cobalt-55 [55Co]||17.5 hours||Characterization of tissue infarct regions|
|Iodine-124 [124I]||4.2 days||Iodination labeling of proteins|
|Zirconium-89 [89Zr]||3.27 days||Biodistribution|
Glucose Metabolism (18F-FDG)
18F-fluorodeoxyglucose (18F-FDG), a glucose analog, is the most common PET radiotracer and is used for assessment of tissue metabolism in a translational manner. As a measure of glucose utilization, 18F-FDG enters the cell via glucose transporters and is irreversibly trapped once it is phosphorylated. Since tumors generally have elevated glucose metabolism, 18F-FDG can be used to characterize pre-treatment metabolic activity, serving as a benchmark to evaluate efficacy and response to therapy. Additionally, 18F-FDG has uses in other therapeutic areas including cardiology, inflammation (e.g., imaging acute inflammation in rheumatoid arthritis), and neurology.
We have extensive experience in running 18F-FDG PET studies across a broad panel of tumor models. This enables us to optimize timing and uptake for imaging in models across a variety of treatment paradigms. Our work has led to clinical development decisions for a number of companies utilizing, or planning to utilize, FDG PET in clinical trials.
Cellular Proliferation (18F-FLT)
Cell proliferation via DNA synthesis can be quantified by imaging with 18F-FLT, the 18F-labeled nucleoside thymidine. After uptake, 18F-FLT is phosphorylated and trapped in proliferating cells. Though 18F-FLT is not incorporated into DNA during the time frame of a typical PET study, it is a measure of thymidine uptake and phosphorylation and therefore can generate biomarkers for proliferation. Based on increased tumor-based specificity of 18F-FLT uptake, signal-to-noise and signal-to-background ratios are generally improved in tumor models for 18F-FLT as compared to 18F-FDG. Therefore, 18F-FLT functions as a reliable biomarker for tumor proliferation in a broad array of tumor models. We have extensive experience with the use and optimization of 18F-FLT PET across models.
New PET Radiotracers
We continually evaluate new radiotracers to address an even broader set of molecular and physiologic questions. Current areas of interest include metabolism (e.g., 18F-fluoro-choline, 18F-fluoro-acetate), hypoxia (e.g., 18F-MISO, 18F-FAZA), apoptosis (e.g., 18F-Annexin-V), and angiogenesis (e.g., 18F-RGD). Contact us to discuss specific PET tracers and applications in discovery and clinical translation.