In multicenter, phase 3 #MITNEC-A1 study, 18F-sodium fluoride PET–CT was compared to 99mTc bone scintigraphy with SPECT in patients with #prostate cancer or #breast cancer at high risk for skeletal metastases and without previously documented bone involvement. 18F-sodium fluoride #PET–CT was found to be significantly more accurate in the detection of bone metastases than 99mTc #bone_scintigraphy with SPECT (84·3% vs 77·4%; p=0·016). This proves that 18F-NaF would displace 99mTc-MDP as the bone imaging radiopharmaceutical of choice in patients with high-risk prostate or breast cancer.