Quantitative [(99m)Tc]Tc-MDP SPECT/CT correlated with [(18)F]NaF PET/CT for bone metastases in patients with prostate cancer

BACKGROUND: The purpose of the present study was to elucidate the correlation between standardized uptake value (SUV) and volume-based parameters measured by quantitative [(99m)Tc]Tc-methylene diphosphonate (MDP) single photon emission computed tomography (SPECT)/CT and [(18)F]-sodium fluoride ([(18)F]NaF) positron emission tomography (PET)/CT in the assessment of bone metastases in patients with prostate cancer. METHODS: The study included 26 male prostate cancer patients with confirmed or suspected bone metastases who underwent both [(99m)Tc]Tc-MDP SPECT/CT and [(18)F]NaF PET/CT studies. Skeletal lesions visible on both SPECT/CT and PET/CT were classified as benign or metastases. The maximum SUV (SUVmax), peak SUV (SUVpeak), mean SUV (SUVmean), metabolic bone volume (MBV), and total bone uptake (TBU) were calculated for every lesion showing abnormal uptake. RESULTS: A total of 202 skeletal lesions (147 benign and 55 metastases) were detected in the 26 patients. Strong significant correlations were noted between SPECT/CT and PET/CT for the SUV- and volume-based parameters (all P < 0.001). The SUVmax, SUVpeak, SUVmean, and TBU values obtained with SPECT/CT were significantly lower than the corresponding values obtained with PET/CT (all P < 0.001). The MBV in SPECT/CT was significantly higher than that in PET/CT (P < 0.001). All SUV- and volume-based parameters obtained with both SPECT/CT and PET/CT for metastatic lesions were significantly higher than the corresponding parameters for benign lesions (P values from 0.036 to < 0.001). CONCLUSIONS: These preliminary results demonstrate that the SUV- and volume-based parameters for bone uptake obtained with quantitative SPECT/CT and PET/CT are strongly correlated in patients with prostate cancer. The SUV parameters obtained with SPECT/CT were significantly lower than those obtained with PET/CT, whereas the uptake volume obtained with SPECT/CT was significantly higher than that obtained with PET/CT.