Development of a simultaneous optical/PET imaging system for awake mice

Area of Science:

• Neuroscience
• Medical Imaging
• Biomedical Engineering

Background:

• Simultaneous measurement of physiological parameters is vital for understanding brain diseases.
• Existing methods may lack the capability for concurrent optical imaging and PET in awake animal models.

Purpose of the Study:

• To develop and validate a novel system for simultaneous optical imaging and Positron Emission Tomography (PET) in awake mice.
• To assess the system's utility in studying brain physiology and disease mechanisms.

Main Methods:

• Development of an open-type PET (OpenPET) system combined with optical imaging and a custom fixation apparatus for awake mice.
• Simultaneous measurement of cerebral blood flow (CBF) using laser speckle imaging (LSI) and [(11)C]raclopride-PET.
• Application of hypercapnia (5% CO2 inhalation) to induce physiological changes.

Main Results:

• The system successfully acquired simultaneous CBF and [(11)C]raclopride PET data in awake mice.
• [(11)C]raclopride accumulation was observed in the striatum, consistent with dopamine D2 receptor density.
• LSI provided stable CBF measurements for over 60 minutes, and hypercapnia-induced increases in CBF were detected.

Conclusions:

• The developed simultaneous optical imaging and PET system is effective for awake animal studies.
• This technology offers a valuable tool for investigating brain disease mechanisms and evaluating therapeutic strategies in relevant models.