Gallium 68- ligand- PSMA PET/CT and PET/MRI in the diagnostic work-up of Prostate Cancer

Introduction: Prostate cancer is the most common non-cutaneous cancer in men, and accounts for almost 10% of cancer-related deaths in males. Gallium 68 (⁶⁸Ga)- ligand-prostate specific membrane antigen (PSMA) is a new radiotracer with great diagnostic potential in patients with prostate cancer. Although there is physiological expression of this transmembrane protein (PSMA) in various organs, it is overexpressed one hundred-fold to one thousand-fold in 95% of prostate cancer cells. The imaging is usually perfomed using PET/CT, and when available with PET/MRI systems. These novel molecular imaging systems may play a major role in the clinical work-up of prostate cancer. The aims of this educational abstract are to: I. Briefly explain the molecular structure of ⁶⁸Ga - ligand PSMA and its uptake mechanism by prostate cancer cells, its normal biodistribution, and the sites of physiologic uptake. II. Review the current literature on the diagnostic performance of ⁶⁸Ga - ligand- PSMA PET/CT and PET/MRI for the evaluation of primary disease, recurrent disease, treatment response monitoring, and biopsy guidance in patients with prostate cancer. III. Discuss the potential pitfalls, including false positive and false negative findings, of ⁶⁸Ga - ligand- PSMA PET/CT and PET/MRI. IV. Evaluate the role of ⁶⁸Ga -PSMA PET/CT and PET/MRI in the selection of patients, who may benefit from targeted systemic radionuclide therapies, such as Lutetium-177 PSMA and Actinium-225 PSMA.