High temporal and spatial resolution upright Motion-tracked Immersive functional PET for behavioral neuroscience

Functional [F18]-fluorodeoxyglucose positron emission tomography (FDG-fPET) is a promising new approach for measuring the dynamic functional changes in the brain related to stimulus and tasks during the scan. However, the fPET has yet to make a significant impact in neuroimaging due to PET’s limited photon detection sensitivity, poor spatial resolution, and subject motion during the task. To fully exploit the benefits of fPET and mitigate its limitations, we propose an ultra-high sensitivity, ultra-high resolution, motion-compensated, portable, and upright Prism-PET brain scanner. This proposed scanner will enable fPET imaging in the sitting position with immersive virtual reality (VR) headsets that can provide enhanced behavioral and visual stimulations. In this study, we designed a synthetic experiment that includes the GATE Zubal brain phantom simulation of brain activations due to visual stimulations. Bolus, constant infusion, and hybrid bolus-infusion injections were simulated, with the gray and white matter uptake modeled using a two-compartment model. A k3 increment was applied to the occipital lobe during the stimulation period and the occipital activity uptake at the end of the experiment is 20% higher than the average gray uptake. We also simulated different frame durations of 1, 5, 15, 30, and 60 seconds. Each frame's image was reconstructed individually using LM-OSEM with DOI-rebinning. The time-to-activity curve of each image voxel was determined and fitted using a general linear model (GLM) with two ground truth task regressors. The activation maps were converted into parametric z-maps, and the sensitivity and specificity of the activated region were calculated. Our simulation results demonstrated that the Prism-PET upright fPET scanner achieved high sensitivity (> 80%) and high specificity (>90%), enabling functional PET imaging with high temporal and spatial resolution.