PET Imaging of the Human Brain with Microvolumetric Spatial Resolution.

Area of Science:

• Neuroimaging
• Medical Physics

Background:

• Positron Emission Tomography (PET) is crucial for in vivo human brain biochemistry and physiology studies.
• Limited spatial resolution of conventional PET restricts visualization of small cerebral structures.

Purpose of the Study:

• To report the achievement of nearly 2 µL volumetric spatial resolution in human brain PET imaging.
• To demonstrate the capability of ultra-high-resolution (UHR) PET to resolve small brain structures.

Main Methods:

• Development of a dedicated UHR PET scanner with 1.2-mm pixelated detectors.
• Acquisition of 18F-FDG PET images of the human brain using the UHR PET scanner.
• Image reconstruction using 3D OSEM with analytic coincidence function modeling and normalization to MNI152 template.

Main Results:

• UHR PET images clearly identified major brain regions and small structures like subthalamic areas and brainstem nuclei.
• Enhanced quantification was suggested by higher SUV ratios in UHR PET compared to PET/CT.
• A hypermetabolic focus in the cerebellum, unseen in PET/CT and MR, was detected in one patient.

Conclusions:

• UHR PET successfully generated human brain images at nearly 2 µL volumetric spatial resolution.
• Previously unresolved small brain regions were visualized, enabling more detailed studies.
• This technology holds potential for advancing neuropsychiatry, neurooncology, and neurodegenerative disease research.