Inclusion Criteria:  Males with 40-85 years of age and life expectancy more than 3 months Patient was diagnosed as mCRPC, and meet the standard criteria of using 223Ra-dichloride (symptomatic bone metastasis, at least two bone metastasis sites, no visceral organ metastasis) Willing to sign the informed consent ECOG performance status Grade 0-2  Exclusion Criteria:  Unable to tolerate the PET/CT scan, such as those with claustrophobia, unable to lie still, consciousness unclear, vital sign unstable. With renal impairment (glomerular filtration rate lower than 30 ml/min/1.73 m2), and allergy to medium contrast. Significant abnormal lab data (AST or ALT more than three times of normal value), and high risk to conduct examination after evaluations of PI. Patient had previous other malignancy history Patient experiences grade 3-4 neutropenia (neutrophil counts less than 1000/uL) or thrombocytopenia (platelet counts less than 50x103/uL) lasting > 14 days