Submillimeter-Resolution PET for High-Sensitivity Mouse Brain Imaging.

Area of Science:

• Medical Imaging
• Neuroscience
• Biomedical Engineering

Background:

• Positron emission tomography (PET) is crucial for molecular imaging but limited by ~1 mm spatial resolution in small animals.
• Visualizing detailed mouse brain function requires higher resolution than current preclinical PET scanners offer.

Purpose of the Study:

• To develop and evaluate an ultrahigh-resolution small-animal PET scanner.
• To achieve improved spatial resolution for detailed mouse brain imaging.

Main Methods:

• Designed a small-animal PET scanner with a 52.5 mm inner diameter and 51.5 mm axial coverage, featuring 4 rings with 16 depth-of-interaction detectors each.
• Utilized 3-layer lutetium yttrium orthosilicate crystal arrays and silicon photomultiplier arrays.
• Evaluated performance using National Electrical Manufacturers Association NU4 protocol and assessed spatial resolution with phantoms. Conducted in vivo glucose metabolism imaging using 18F-FDG.

Main Results:

• Achieved a peak absolute sensitivity of 2.84% (400-600 keV energy window).
• Resolved a 0.55-mm rod structure in a phantom using iterative reconstruction.
• Successfully visualized mouse brain structures like the cortex, thalamus, and hypothalamus with 18F-FDG, surpassing a commercial preclinical PET scanner's detail.

Conclusions:

• The developed ultrahigh-resolution PET scanner provides ~0.6 mm resolution, significantly enhancing visualization of mouse brain function.
• This technology is a promising tool for neuroscience research, particularly in rodent models.
• Enables detailed study of brain metabolism and function at an unprecedented level.