In a specific application of pH in medical science, for instance, when labelling Prostate-specific membrane antigen (PSMA) peptide with lutetium-177 (Lu-177) or actinium-225 (Ac-225) in the radiopharmaceutical treatment of prostate cancer, the pH of the radioactive lutetium or actinium must be at pH = 9 to allow for complete binding of the peptide. This evidence concerns the gene FOLH1 and prostate cancer.