Figure 1.

Schematic structure of the theranostic probe LC-Pyro (long-circulating pyropheophorbide a), which is comprised of three building blocks: (1) a porphyrin photosensitizer capable of deep-red fluorescence imaging and ⁶⁴Cu chelation for PET imaging; (2) a 9-amino acid d- peptide sequence that imparts water-solubility and prolongs plasma circulation to promote tumor accumulation; and (3) a high-affinity urea-based small-molecule PSMA targeting ligand.