Strontium chloride [89Sr] is a therapeutic agent for metastatic cancer bone pain, mainly used for the relief of bone pain caused by bone metastases secondary to advanced malignant tumors such as prostate cancer and breast cancer, and is a therapy for pain relief of metastatic cancer bone pain. Principle】89Sr has a long half-life and is osteophilic. Osteogenic bone metastases can take in more radiopharmaceuticals and continuously emit β-rays, which can provide pain relief and even inhibit the growth of bone metastases or make bone metastases shrink. Indications】 1. Pain caused by multiple bone metastases. 2.Bone metastases are radiologically distributed and concentrated, and the pain site is consistent with this site. Contraindications】 1.Pregnancy and lactation. 2.White blood cell WBC＜3.5×109/L, platelet＜80×109/L. 3.Severe liver and kidney function impairment. Efficacy testing】 1.Check blood routine, liver and kidney function every month after treatment. 2.Record the change of pain every month after treatment. 3.Compare the changes of metastases with whole body bone imaging every 3 months after treatment. Precautions】 1.This method is palliative treatment and cannot guarantee the effectiveness of every patient. 2. This method can only inhibit the growth of metastases, but cannot completely cure the cancer.