FOLH1 and neoplasm: The NB fluorescence ratio (quantification of fluorescence ratio from total bubbles fluorescence/vessels fluorescence and total bubbles fluorescence/cells fluorescence per field) in PSMA-targeted NBs group was significantly higher than that in non-targeted NBs group (Fig. 6b1,b2), which confirmed that PSMA-targeted NBs not only can extravasate into the tumor but also can be trapped within the tumor.