Comparison of Ga-FAPI-04 and Ga-PSMA in a Case of Interstitial Lung Disease.

We present the Ga-prostate-specific membrane antigen (PSMA) and Ga-fibroblast activation protein inhibitor (FAPI)-04 positron emission tomography/computed tomography (PET/CT) findings comparatively of a 76-year-old man with a history of progressive dyspnea and evidence of interstitial lung disease (ILD) abnormalities on high-resolution CT. Moderate PSMA uptake was observed in areas with ILD abnormalities on Ga-PSMA PET/CT. Ga-FAPI-04 PET/CT showed relatively higher FAPI-04 uptake in these regions. These findings offer the potential to assess disease activity at the cellular and molecular levels. This approach may provide valuable insight into the pathophysiology of ILD beyond the structural changes captured by traditional imaging methods.