Dynamic PET and Optical Imaging and Compartment Modeling using a Dual-labeled Cyclic RGD Peptide Probe

Area of Science:

• Molecular Imaging
• Biomedical Optics
• Radiochemistry

Background:

• Positron Emission Tomography (PET) is a powerful molecular imaging technique.
• Dynamic PET imaging provides quantitative kinetic parameters.
• Optical imaging offers potential advantages but often lacks quantitative accuracy.

Purpose of the Study:

• To evaluate dynamic optical imaging's ability to yield kinetic parameters comparable to dynamic PET.
• To assess a near-infrared dye/(64)Cu dual-labeled cyclic RGD peptide for imaging integrin α(v)β(3).

Main Methods:

• A cyclic RGD peptide was conjugated with a near-infrared dye (ZW-1) and a copper chelator (DOTA).
• In vitro assays confirmed biological activity and integrin binding.
• Dynamic PET and 2D optical imaging were performed on a tumor model, analyzed using singular value decomposition (SVD) and compartment models.

Main Results:

• The dual-labeled probe demonstrated specific integrin binding in vitro and in vivo.
• Binding potential (Bp) values from dynamic optical imaging (1.762 ± 0.020) closely matched dynamic PET (1.752 ± 0.026).
• SVD analysis improved the accuracy of kinetic modeling for 2D dynamic optical data.

Conclusions:

• Singular value decomposition enhances the quantitative accuracy of dynamic optical imaging.
• 2D dynamic optical imaging, when combined with SVD, can achieve quantitative results comparable to dynamic PET.
• This approach shows promise for preclinical molecular imaging applications.