e14608 Background: Identifying predictive markers for toxicity could decrease the number of patients experiencing dose-limiting toxicity. The study aims to investigate whether 18F-Alfatide positron emission tomography (PET) can predict the antiangiogenic drugs toxicity. Methods: A549 xenografted mice underwent 18F-Alfatide PET at baseline when tumor volume reached 100-200 mm3 and after treatment with apatinib (100mg/kg once daily), bevacizumab (20mg/kg every four days), endostar (20mg/kg once daily) or vehicle. Tumor growth and body weight were monitored every two days. The changed rate of tumor volume (TV) and organ uptake (OU) after therapy were calculated using the formula: [mean value(negative control) – each value(experimental)]/mean value(negative control)×100%, and [each value(experimental) – mean value(negative control)]/mean value(negative control)×100% for pathological injury degree of organs (PID) after therapy. We compared the antiangiogenic response and organs PID among three groups. Then, linear correlation was analyzed between mean OU and mean TV or mean PID, and between organ uptakes before treatment and PIDs in all model group. Results: TVs treated by endostar was lower than that of bevacizumab, both of which were lower than that of apatinib (mean IR±SD: endostar (13.56±11.78)%, bevacizumab (37.19±12.50)% and apatinib (48.43±8.71)%, respectively, P > 0.05 for the three groups, but P < 0.05 for the comparison of endastar and apatinib groups). The same is true for the PIDs (mean PID±SD for livers: endostar (32.58±11.81) %, bevacizumab (36.12±11.01)% and apatinib (41.12±9.99)%, P > 0.05; mean PID±SD for kidneys: endostar (39.54±4.80)%, bevacizumab (43.24±5.46)% and apatinib (52.90±8.75)%, P > 0.05). There was an excellent linear relationship between mean OU and mean PID (Liver: R2= 0.93, P > 0.05 for OUSUVmean; R2= 0.80, P > 0.05 for OUSUVmax; Kidney: R2= 0.85, P > 0.05 for OUSUVmean; R2= 0.97, P > 0.05 for OUSUVmax) and an excellent linear relationship between mean OU and mean IR (Liver: R2= 0.99, P < 0.05 for OUSUVmean; R2 = 0.97, P > 0.05 for OUSUVmax; Kidney: R2= 0.99, P < 0.05 for OUSUVmean; R2= 0.93, P > 0.05 for OUSUVmax). There was a significantly moderate linear association between the uptakes of organs prior to treatment and the PIDs (Liver: R2= 0.49, P < 0.001 for OUSUVmean; R2= 0.45, P < 0.001 for OUSUVmax; Kidney: R2= 0.57, P < 0.0001 for OUSUVmean; R2= 0.53, P < 0.001 for OUSUVmax). Conclusions: 18F-Alfatide PET may be a useful molecular imaging tool for individual selection with toxicity before antiangiogenic therapy.