High throughput static and dynamic small animal imaging using clinical PET/CT: potential preclinical applications

Area of Science:

• Medical Imaging
• Preclinical Research
• Nuclear Medicine

Background:

• Clinical Positron Emission Tomography/Computed Tomography (PET/CT) systems are increasingly advanced.
• Simultaneous imaging of multiple small animals can enhance research efficiency.
• Evaluating the quantitative accuracy of clinical PET/CT for small animal studies is crucial.

Purpose of the Study:

• To assess the capability of modern clinical PET/CT scanners for simultaneous static and dynamic imaging of multiple mice.
• To validate the quantitative accuracy of this approach using phantom and in vivo studies.
• To determine the feasibility of using clinical PET/CT for high-throughput preclinical research.

Main Methods:

• Utilized a mouse-sized phantom to compute recovery coefficients (RCs) and spillover ratios (SORs) for simultaneous imaging.
• Performed static PET/CT imaging of tumor-bearing mice (n=15) using [18F]fluorodeoxyglucose or [18F]fluorothymidine with Point Spread Function (PSF) reconstruction.
• Conducted dynamic imaging with 68Ga-ethylenediaminetetraacetic acid (EDTA) in three simultaneously imaged mice and compared results with ex vivo gamma counting.

Main Results:

• Point Spread Function (PSF) reconstruction yielded higher recovery coefficients (0.76) compared to OSEM (0.42) for phantom lesions.
• Strong correlation (r²=0.97) observed between quantitative data from single and simultaneous mouse imaging with PSF reconstruction.
• PET/CT data showed excellent agreement with ex vivo gamma counting (r²=0.98) when using PSF reconstruction.

Conclusions:

• State-of-the-art clinical PET/CT scanners are suitable for simultaneous imaging of multiple mice.
• This method offers a viable alternative for high-throughput preclinical studies, especially when dedicated small animal PET systems are inaccessible.
• Accurate quantitative data can be obtained, enabling reliable research outcomes.