Theragnostic agents in PET combine which capabilities?

• A. Diagnostic only
• B. Imaging only
• C. Both diagnostic and therapeutic
• D. Therapeutic only

Answer: (C)

Theragnostic agents in PET fuse diagnostic imaging with targeted therapy in a single concept. They use a molecular target on tumor cells so that a diagnostic radiopharmaceutical can image and quantify how much target is present, guiding patient selection and treatment planning. The same or a closely related agent then carries a therapeutic radionuclide to deliver cytotoxic radiation to the tumor, providing treatment. Classic examples include imaging with Ga-68 DOTATATE to assess somatostatin receptor expression and treating with Lu-177 DOTATATE, and similar PSMA-targeted pairs for prostate cancer. So, these agents combine diagnostic and therapeutic capabilities.