In order to select the most promising Tzs, we plotted the in vitro Cor/Cer ratio against the in vivo peak/AUC ratio (Figure ). None of these ligands appeared to be ideal, i.e., neither had the highest rank in both categories simultaneously. Consequently, we decided to test the three most promising Tzs identified in this plot, namely, [ 18 F]12, [ 18 F]10 and [ 18 F]14 as well as two low ranking Tzs in order to verify that our model holds and can predict the in vivo performance of these structures.