Figure 5.

Non-invasive PET imaging of ⁶⁸Ga-DOTA-A2B1 with/without a blocking dose of c(DGEAyK) peptide and ¹⁸F-FDG in integrin α2β1-positive A549 and CL1-5 xenograft mouse models. (A) Decay-corrected whole-body planar coronal PET images of the A549 (or CL1-5) tumor-bearing animal model at 10 min post-injection of 7-8 MBq of ⁶⁸Ga-DOTA-A2B1 or 11.1 MBq¹⁸F-FDG tracer (p.i. 60 min). The blocking group was injected with a high dose of the non-radiolabeled c(DGEAyK) peptide (10 mg/kg), and all images are coronal views. The tumors are indicated with arrows. (B) Region of interest (ROI) analysis of the PET images showing ⁶⁸Ga-DOTA-A2B1 and ¹⁸F-FDG uptake values in the tumor and major organs, such as the heart, lung, kidneys, liver and muscle; values are presented as the % ID/g ± SD (n = 5). The quantified PET imaging data (Figure 5B) indicated the binding specificity and favorable biodistribution pattern of integrin tracers. The tumor/muscle ratios of the ⁶⁸Ga-DOTA-A2B1 A549 (n = 5) and CL1-5 (n = 5) groups were significantly better (*p) than that of the ¹⁸F-FDG group (n = 5), in which the A549 tumor was barely visible (p < 0.05). High integrin tracer retention occurred in the urogenital tract due to predominant renal clearance, and intermediate uptake was found in the liver. *p < 0.05; *** p < 0.001.