Can 99mTc-PSMA SPECT/CT Presenting Mirror Image of 68Ga-PSMA PET/CT Be Used for Response Assessment to 177Lu-PSMA in Metastatic Castration-Resistant Prostate Cancer?

A 69-year-old man, with a known case of metastatic castration-resistant prostate cancer (mCRPC) underwent 68Ga-PSMA PET/CT and 99mTc-PSMA for evaluation of disease burden and response assessment to 177Lu-PSMA therapy. 99mTc-PSMA provided a mirror image of 68Ga-PSMA. This suggests the potential of 99mTc-PSMA SPECT/CT for disease evaluation and response assessment to PSMA-based radioligand therapies in advanced-stage mCRPC patients, especially when 68Ga-PSMA PET/CT is not available.