Multiple imaging modalities are available to evaluate recurrent prostate cancer following primary treatment with RP, RT, or cryo-surgery. These tests must be used in close conjunction with clinical parameters, such as the characteristics of the tumor itself (grade, stage) as well as specific PSA characteristics that can help predict the sites of probable recurrence. Figure 19 represents an algorithm of how patients can be monitored for recurrence according to their mode of primary treatment. As more treatments become available for recurrent prostate cancer, it will be necessary to monitor disease response with many of the imaging modalities discussed in this article.