In the largest pre-operative series reported, our group found bone metastases in 13/130 patients pre-operatively; 2 of the 13 patients had bone metastases that had not been detected previously by conventional imaging (Fig. 2) [3]. The results of the study showed that FCH PET/CT would result in a therapy change for 15% of patients overall, and an upstaging change in 20% of high-risk patients. In evaluating 70 men with PCa, our group noted sensitivity, specificity and accuracy of 79%, 97% and 84%, respectively, for FCH PET/CT compared with a consensus definition of bone metastases based on conventional imaging and clinical endpoints [8]. In another prospective series of 38 patients with high-risk PCa [9], we compared the performance of FCH PET/CT with that of [¹⁸F]fluoride PET/CT (Table 1). FCH PET/CT showed significantly higher specificity than [¹⁸F]fluoride PET/CT and comparable sensitivity. However superior performance in the detection of bone marrow metastases was seen using FCH PET imaging. In those studies, discordant findings were noticed in a relatively small subset of patients with densely sclerotic lesions on CT that were negative in FCH PET and positive in [¹⁸F]fluoride PET scans (Fig. 3).