FAPI-based MR targeted imaging contrast agent and preparation method thereof

The invention discloses an FAPI-based MR targeted imaging contrast agent, which comprises the following components: nanoparticles, a ligand and a targeting agent, the ligand and the targeting agent are sequentially solidified on the surface of the nanoparticles from inside to outside, and the targeting agent is specifically a combination of an MR contrast agent with a paramagnetic effect and a targeting substance FAPI; the preparation method comprises the following steps: carrying out pore-forming treatment on the nanoparticles to form pores, and modifying the whole pores to form a plurality of layers of rough surfaces; soaking the ligand in the medicine solution to prepare a primary product; forming a new rough surface on the surface of the combination of each layer of nanoparticles and the primary product until the rough surface with the specified layer number is completed, and curing; and mixing the cured combination with a targeting agent, fully soaking, and curing to prepare the FAPI-based MR targeting i