Multi-organ kinetic modeling for Na[¹⁸F]F pre-clinical total-body PET studies

Area of Science:

• Nuclear Medicine
• Pharmacokinetics
• Pre-clinical Imaging

Background:

• Total-body positron emission tomography (PET) allows whole-body biological system analysis.
• Simultaneous kinetic analysis of multiple organs presents significant challenges.

Purpose of the Study:

• To quantify in vivo pharmacokinetics of Na[18F]F in multiple murine organs simultaneously.
• Utilize total-body PET imaging with distinct compartmental models per organ and a shared cardiovascular system.

Main Methods:

• Six mice underwent 60-min total-body PET scans after Na[18F]F injection.
• Developed compartmental models for heart, lungs, liver, kidneys, and bone with an image-derived input function.
• Applied non-linear least squares fitting to a model connecting five organs to a shared cardiovascular system, analyzing 3-min and 60-min data.

Main Results:

• Models provided good qualitative fits to activity curves for both data durations; 3-min data yielded better fits.
• Perfusion values for liver (0.540 ± 0.177 mL/mL/min) exceeded expectations, while lung values (0.184 ± 0.413 mL/mL/min) were in rough agreement.
• Correlations between microparameters, particularly affecting k2, complicated data modeling for kidneys and femur.

Conclusions:

• Demonstrated a viable approach for simultaneous kinetic modeling of multiple organs using Na[18F]F.
• Inter-microparameter correlations remain a challenge for accurate modeling.
• Reliable estimation of many microparameters and quantitative perfusion analysis in select organs is achievable.