TSPO and rheumatoid arthritis: Bruijnen et al. [148] studied the relatively less lipophilic O-[18F]fluoroethylated DPA-TSPO tracer [18F]DPA-714 (Figure 2) (ClogP 3.3) and its O-[11C]methylated analog [11C]DPA-713 (ClogP 3.1) in RA patients.