FOLH1 and prostate carcinoma: However, there are certain limitations that are becoming increasingly apparent: (i) authorized generators are expensive and have a limited production capacity (the maximum number of patient doses per synthesis is 2–3, depending on the age of the generator), and (ii) access to gallium-68 is increasingly limited because another 68Ga-labeled tracer ([68Ga]Ga-PSMA-11, where PSMA = prostate specific membrane antigen) has also received FDA/EMA approval for PET imaging of prostate cancer and is in broad clinical use.