Pictorial essay: normal variants, lesions, and pitfalls in Ga-68-PSMA PET imaging of prostate cancer.

Prostate-specific membrane antigen (PSMA) is a type II transmembrane protein with glutamate carboxypeptidase/folate hydrolase activity. PSMA is physiologically expressed in most prostate cancer (PCa) cells. Gallium-based [68 Ga]–PSMA–HBED (or PSMA 11) is the most widely employed radiopharmaceutical worldwide. Gallium-based [68 Ga]–PSMA–HBED (or PSMA 11) has been recently introduced in the clinical practice, and therefore, it has created the need for a precise knowledge of its normal distribution over time, requiring familiarity with its physiological or benign variants and, most importantly, with the most common causes of pitfalls. In this short essay, we have tried to summarize the most commonly observed 68 Ga–PSMA–HBED PET/CT findings which may potentially fall within this category and, therefore, be a source of misinterpretation.