GPC3 and hepatocellular carcinoma: Although the peak CNR was comparable between ET58-DOTA-Gd and DOTA-Gd, ET58-DOTA-Gd maintained a higher CNR for a prolonged period of time, even after that of DOTA-Gd had declined after 120 min, suggesting prolonged retention of ET58-DOTA-Gd in GPC3-expressing HCC cells.