Comparison of four C-labeled PET ligands to quantify translocator protein 18 kDa (TSPO) in human brain: (R)-PK11195, PBR28, DPA-713, and ER176-based on recent publications that measured specific-to-non-displaceable ratios.

Translocator protein (TSPO) is a biomarker for detecting neuroinflammation by PET. C-(R)-PK11195 has been used to image TSPO since the 1980s. Here, we compared the utility of four C-labeled ligands-(R)-PK11195, PBR28, DPA-713, and ER176-to quantify TSPO in healthy humans.