Dynamic (Functional) PET and MR-PET Imaging
A relatively broad array of radiotracers has been developed for this purpose, many for human use, but a critical element is missing from this toolbox. By and large (with only a few exceptions), radiotracers are designed to determine a state-function of the brain and are not capable of measuring neurochemical dynamics. While PET scientists routinely acquire “dynamic” data, these data are typically fit for static state measure of tracer transport kinetics and receptor binding potentials. We are working on imaging methods and new radiotracer concepts that enable greater temporal resolution for PET imaging.
fPET-FDG: Glucose is the principal source of energy for the brain and yet the dynamic response of glucose utilization to changes in brain activity is still not fully understood. Positron emission tomography (PET) allows quantitative measurement of glucose metabolism using 2-[18F]-fluorodeoxyglucose (FDG). However, FDG PET typically provides an integral (or average) of glucose consumption over tens of minutes and lacks the temporal information to capture physiological alterations associated with changes in brain activity induced by tasks or drug challenges. Traditionally, changes in glucose utilization are inferred by comparing two separate scans, which significantly limits the utility of the method. We have developed and are using a method to track changes in FDG metabolism dynamically, with higher temporal resolution than exists to date and within a single session.