Comparison of Ga-68-DOTA-Siglec-9 and F-18-Fluorodeoxyribose-Siglec-9: Inflammation Imaging and Radiation Dosimetry

Abstract

Sialic acid-binding immunoglobulin-like lectin 9 (Siglec-9) is a ligand of inflammation-inducible vascular adhesion protein-1 (VAP1). We compared Ga-68-DOTA-and F-18-fluorodeoxyribose-(FDR) labeled Siglec-9motif peptides for PET imaging of inflammation. Methods. Firstly, we examined Ga-68-DOTA-Siglec-9 and F-18-FDR-Siglec-9 in rats with skin/muscle inflammation. We then studied F-18-FDR-Siglec-9 for the detection of inflamed atherosclerotic plaques in mice and compared it with previous Ga-68-DOTA-Siglec-9 results. Lastly, we estimated human radiation dosimetry fromthe rat data. Results. In rats, Ga-68-DOTA-Siglec-9 (SUV, 0.88 +/- 0.087) and F-18-FDR-Siglec-9 (SUV, 0.77 +/- 0.22) showed comparable (P = 0.29) imaging of inflammation. In atherosclerotic mice, 18 FFDR- Siglec-9 detected inflamed plaques with a target-to-background ratio (1.6 1/8 0.078) similar to previously tested Ga-68-DOTASiglec- 9 (P = 0.35). Humaneffectivedose estimates for Ga-68-DOTA-Siglec-9 and (18) F-FDR-Siglec-9were 0.024 and 0.022 mSv/MBq, respectively. Conclusion. Both tracers are suitable for PET imaging of inflammation. The easier production and lower cost of (68)GaDOTA-Siglec-9 present advantages over F-18-FDR-Siglec-9, indicating it as a primary choice for clinical studies.