Comparison of Ga-DOTA-Siglec-9 and F-Fluorodeoxyribose-Siglec-9: Inflammation Imaging and Radiation Dosimetry.

Sialic acid-binding immunoglobulin-like lectin 9 (Siglec-9) is a ligand of inflammation-inducible vascular adhesion protein-1 (VAP-1). We compared Ga-DOTA- and F-fluorodeoxyribose- (FDR-) labeled Siglec-9 motif peptides for PET imaging of inflammation. . Firstly, we examined Ga-DOTA-Siglec-9 and F-FDR-Siglec-9 in rats with skin/muscle inflammation. We then studied F-FDR-Siglec-9 for the detection of inflamed atherosclerotic plaques in mice and compared it with previous Ga-DOTA-Siglec-9 results. Lastly, we estimated human radiation dosimetry from the rat data. . In rats, Ga-DOTA-Siglec-9 (SUV, 0.88 ± 0.087) and F-FDR-Siglec-9 (SUV, 0.77 ± 0.22) showed comparable ( = 0.29) imaging of inflammation. In atherosclerotic mice, F-FDR-Siglec-9 detected inflamed plaques with a target-to-background ratio (1.6 ± 0.078) similar to previously tested Ga-DOTA-Siglec-9 ( = 0.35). Human effective dose estimates for Ga-DOTA-Siglec-9 and F-FDR-Siglec-9 were 0.024 and 0.022 mSv/MBq, respectively. . Both tracers are suitable for PET imaging of inflammation. The easier production and lower cost of Ga-DOTA-Siglec-9 present advantages over F-FDR-Siglec-9, indicating it as a primary choice for clinical studies.