Prostate-specific membrane antigen (PSMA) overexpression on prostate cancer cells finally led to the FDA approval of the therapeutic use of 177Lu-PSMA-617 in metastatic castrate-resistant prostate cancer. However, PSMA is also expressed in the neovasculature of other solid tumors, such as lung and renal cancer, making the theranostic potential of 177Lu-PSMA-617 worth exploring in this setting. Here is such a case of an 83-year-old man with advanced non-small cell lung cancer where the theranostic potential of 177Lu-PSMA-617 was explored using dosimetric analysis.