AIM: To compare 2-deoxy-2-(~(18)F)fluoro-D-glucose(~(18)FFDG) and ~(18)F-sodium(~(18)F-NaF) positron emission tomography/computed tomography(PET/CT) accuracy in breast cancer patients with clinically/radiologically suspected or known bone metastases.METHODS: A total of 45 consecutive patients with breast cancer and the presence or clinical/biochemical or radiological suspicion of bone metastatic disease underwent ~(18)F-FDG and ~(18)F-fluoride PET/CT. Imaging results were compared with histopathology when available, or clinical and radiological follow-up of at least 1 year. For each technique we calculated: Sensitivity(Se), specificity(Sp), overall accuracy, positive and negative predictive values, error rate, and Youden’s index. Mc Nemar’s χ~2 test was used to test the difference in sensitivity and specificity between the two diagnostic methods. All analyses were computed on a patient basis, and then on a lesion basis, with consideration ofthe density of independent lesions on the coregistered CT(sclerotic, lytic, mixed, no-lesions) and the divergent site of disease(skull, spine, ribs, extremities, pelvis). The impact of adding ~(18)F-Na F PET/CT to the work-up of patients was also measured in terms of change in their management due to ~(18)F-Na F PET/CT findings. RESULTS: The two imaging methods of ~(18)F-FDG and ~(18)F-fluoride PET/CT were significantly different at the patient-based analysis: Accuracy was 86.7% and 84.4%, respectively(Mc Nemar’s χ~2 = 6.23, df = 1, P = 0.01). Overall, 244 bone lesions were detected in our analysis. The overall accuracy of the two methods was significantly different at lesion-based analysis(Mc Nemar’s χ~2 = 93.4, df = 1, P < 0.0001). In the lesion density-based and site-based analysis, ~(18)F-FDG PET/CT provided more accurate results in the detection of CT-negative metastasis(P < 0.002) and vertebral localizations(P < 0.002); ~(18)F-Na F PET/CT was more accurate in detecting sclerotic(P < 0.005) and rib lesions(P < 0.04). ~(18)F-Na F PET/CT led to a change of management in 3 of the 45 patients(6.6%) by revealing findings that were not detected at ~(18)F-FDG PET/CT. CONCLUSION: ~(18)F-FDG PET/CT is a reliable imaging tool in the detection of bone metastasis in most cases, with a diagnostic accuracy that is slightly, but significantly, superior to that of ~(18)F-Na F PET/CT in the general population of breast cancer patients. However, the extremely high sensitivity of ~(18)F-fluoride PET/CT can exploit its diagnostic potential in specific clinical settings(i.e., small CT-evident sclerotic lesions, high clinical suspicious of relapse, and negative ~(18)F-FDG PET and conventional imaging). AIM: To compare 2-deoxy-2- (~ (18) F) fluoro-D-glucose and 18-18 F-NaF positron emission tomography / computed tomography (PET / CT) accuracy in breast cancer patients with clinically / radiologically suspected or known bone metastases. METHHODS: A total of 45 consecutive patients with breast cancer and the presence or clinical / biochemical or radiological suspicion of bone metastatic disease underwent ( 18) F-FDG and ~ (18) F-fluoride PET / CT. Imaging results were compared with histopathology when available, or clinical and radiological follow-up of at least 1 year. For each technique we calculated: Sensitivity (Se), specificity (Sp), overall accuracy, positive and negative predictive values, error rate, and Youden’s index. Mc Nemar’s χ ~ 2 test was used to test the difference in sensitivity and specificity between the two diagnostic methods. All analyzes were computed on a patient basis, and then on a lesion basis, with consideration of the density of independent lesions on the co The impact of adding ~ (18) F-Na F PET / CT to the work-on CT (sclerotic lytic, mixed, no- lesions) and the divergent site of disease (skull, spine, ribs, extremities, pelvis) up of patients was also measured in terms of change in their management due to ~ (18) F-Na F PET / CT findings. RESULTS: The two imaging methods of ~ (18) F-FDG and ~ Overall, 244 bone lesions were detected in our analysis (86%) and 84.4% (McNemar’s χ ~ 2 = 6.23, df = 1, P = . The overall accuracy of the two methods was significantly different at lesion-based analysis (McNemar’s χ ~ 2 = 93.4, df = 1, P <0.0001). In the lesion density- F-FDG PET / CT provided more accurate results in the detection of CT-negative metastasis (P <0.002) and vertebral localizations (P <0.002) P <0.005) and rib lesions (P <0.04) ) F-Na F PET / CT led to a change of management in 3 of the 45 patients (6.6%) by revealing findings that were not detected at ~ (18) F-FDG PET / CT. CONCLUSION: / CT is a reliable imaging tool in the detection of bone metastasis in most cases, with a diagnostic accuracy that is slightly, but significantly, superior to that of ~ (18) F-Na F PET / CT in the general population of breast cancer However, the extremely high sensitivity of ~ 18 F-fluoride PET / CT can exploit its diagnostic potential in specific clinical settings (ie, small CT-evident sclerotic lesions, high clinical suspicious of relapse, and negative ~ (18) F-FDG PET and conventional imaging).