Fig. 3
![Fig. 3](http://media.springernature.com/full/springer-static/image/art%3A10.1186%2Fs12951-022-01355-3/MediaObjects/12951_2022_1355_Fig3_HTML.png)
In vivo MR contrast properties of FeCO3 NPs. A in vivo (n = 3) T2-weighted MR images of lung tumors pre and post-1 h, 3 h, 5 h injection of PBS and FeCO3 NPs (dose of NPs; 10 mg Fe ion/kg, i.v injection, MRI scans were performed on a 9.4 T MRI scanner, circle/pseudo color indicates the tumor region). B Kinetic plot of in vivo contrast ability of PBS and FeCO3 NPs, data is represented as mean ± SD; ***P ≤ 0. 001. C Schematic representation of in vivo MR imaging of lung tumors using FeCO3 NPs on a 9.4 T MRI scanner