A 68-year-old man with metastatic castration-resistant prostate cancer undergoes Ga-68 PSMA PET-CT, which shows intense PSMA uptake in pelvic lymph nodes and vertebral metastases. He is planned for targeted radionuclide therapy. Which radiopharmaceutical is the most appropriate therapeutic agent?
- A I-131 MIBG
- B Lu-177 PSMA-617 ✓
- C Y-90 microspheres
- D Ra-223 dichloride
Correct answer: B. Lu-177 PSMA-617
Explanation
Lu-177 PSMA-617 is a beta-emitting radioligand that binds to prostate-specific membrane antigen, delivering targeted radiation to PSMA-expressing metastases. It is the therapeutic component of the Ga-68 PSMA/Lu-177 PSMA theranostic pair. Ra-223 dichloride is an alpha emitter for osteoblastic bone metastases but does not target PSMA. I-131 MIBG is used for neuroendocrine tumours such as pheochromocytoma. Y-90 microspheres are used for intra-arterial radioembolisation of liver tumours.
Reference: Harrison's Principles of Internal Medicine, 21st ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.