Figure 2. Tumor-targeted radionuclide therapy.

A: PET scans of somatostatin receptor-targeted ⁶⁸Ga-DOTATOC in a patient with atypical lung carcinoids before and after peptide receptor-based radionuclide therapy (2 cycles ⁹⁰Y-DOTATOC and 1 cycle ¹⁷⁷Lu-DOTATATE). B: PET scans obtained using ⁶⁸Ga-PSMA-11 in a patient with metastatic castration-resistant prostate cancer prior to and after 4 cycles of radiopharmaceutical therapy with ¹⁷⁷Lu-PSMA-617. C: PET scans obtained using cancer-associated fibroblast-targeted ⁶⁸Ga-FAPI exemplify probe enrichment in various different tumor types. D: Biodistribution and target site localization of the ⁸⁹Zr-labeled and HER2-specific antibody trastuzumab at 5 days after i.v. administration in breast cancer patients with brain and bone metastases. E: Biodistribution and tumor accumulation of HER2-specific nanobodies labeled with ⁶⁸Ga at 90 minutes after i.v. injection in patients with high (1) and medium (2) HER2 expression in breast tumors. F: Pretargeting approaches based on the initial injection of trans-cyclooctyne-modified antibodies (anti-TAG72; left) or nanoparticles (Peptobrushes; right), followed by a waiting time and then injection of tetrazine-based chelators labeled with ¹¹¹In. Images reproduced with permission from refs ^26,28–33