Given that [ 18 F]2 can assess ALDH activity in SKOV3-ip1 and SKOV3-TRip2 cells with high sensitivity and specificity, we next explored [ 18 F]2's ability to detect ALDH activity in tumour-bearing mice. Dynamic [ 18 F]2 PET/CT imaging was performed at low and high MAs to understand the effect of radiotracer metabolism on its pharmacokinetics and tumour retention. [ 18 F]2 was characterised by rapid extraction from the blood and excretion through the urinary tract (Fig. ). At early time points, high [ 18 F]2 uptake was evident in the lung and liver, with liver uptake peaking at 3 and 5 min for low and high MAs, respectively (18.2 ± 2.9% ID/mL and 19.8 ± 2.4% ID/mL; Fig. ).