Prostate cancer represents the most common cancer in men and accounts for the third most common cancer death in men. Up to 50% of all patients undergoing radical prostatectomy or radiotherapy for primary treatment of prostate cancer develop biochemical recurrence. Early detection of primary diseases and recurrence is crucial for patient counseling and management. Conventional imaging modalities such as computed tomography (CT) or magnetic resonance imaging (MRI) are limited because they focus on morphologic information such as lymph node size and tissue structure.