Constant Infusion Radiotracer Administration for High Temporal Resolution Positron Emission Tomography (PET) of the Human Brain: Application to -Fluorodexoyglucose PET (FDG-PET)

Functional Positron Emission Tomography (fPET) provides a method to track molecular dynamics in the human brain. With a radioactively labelled glucose-analogue, [18F]-flurodeoxyglucose (FDG-fPET), it is now possible to index the dynamics of glucose metabolism with temporal resolutions approaching those of functional magnetic resonance imaging (fMRI). This direct measure of glucose uptake has enormous potential for understanding normal and abnormal brain function, and probing the effects of metabolic and neurodegenerative diseases. Further, new advances in hybrid MR-PET hardware makes it possible to capture fluctuations in glucose and blood oxygenation simultaneously using fMRI and FDG-fPET.\n\nThe temporal resolution and signal-to-noise of the FDG-fPET images is critically dependent upon the administration of the radioactive tracer. In this work we present two alternative continuous infusion protocols and compare them to a traditional bolus approach. We detail a method for acquiring blood samples, time-locking PET, MRI and experimental stimulus, and administrating the non-traditional tracer delivery. By applying a visual stimulus, we demonstrate cortical maps of the glucose-response to external stimuli on an individual level with a temporal resolution of 16-seconds.\n\nSummaryRadiotracer infusion protocols for positron emission tomography (PET) provide improved temporal resolution over bolus administration. Here, we describe radiotracer administration for two protocols, constant infusion and bolus plus infusion protocol. We compare this to the standard bolus administration protocol. Using [18-F] fluorodeoxyglucose PET (FDG-PET) as an example, we show that temporal resolutions of approximately 16sec are achievable using these protocols.