NK224 is a peptide-based radiotracer targeting human PD-L1, designed for dual radionuclide labeling compatibility using a NOTA chelator with both [68Ga and 18F]. It exhibits high binding affinity to PD-L1, with an IC50 value of 2.45 nM. NK224 enables visualization of tumor heterogeneity in patients and dynamic monitoring of PD-L1 target occupancy during immunotherapy. It is applicable to non-small cell lung cancer (NSCLC) research.