ADRB2 and neoplasm: Fig. 5A showed that SNAPf-ADRβ2 expressing tumor could be visualized by BG-800 at 24 h post injection. The higher fluorescence signal in Tm-S was revealed more clearly by ex vivo imaging after tissue dissection (Fig. 5A, inset). The ratios of Tm-S/Tm-C and Tm-S/muscle were 3.31±0.43 and 12.3±2.9, respectively. However, it was noticed that the background fluorescence signal was high. This high background signal might be caused by accumulation of BG-800 in the skin, as demonstrated by ex vivo imaging analysis (Fig. 5B).