Abstract: THE CLINICAL COMPARISION OF TWO DOSAGES OF 153SmEDTMP AS PALLIATION OF PAINFUL BONE METASTASES Tian Jiahe① Zhang Jiming① Hou Qingtian② Ouyang Qiaohong③ Chuan Ling④ He Yijie① (①The Chinese PLA General Hospital,100853)\ (②Hangang General Hospital,Handan 056001) (③Yuyuantan Hospital, Beijing 100039)\ (④Navy General Hospital,Beijing 100037) ABSTRACT Different dosages of 153SmEDTMP are injected intravenously into 80 patients of bone pain caused by metastases. The patients are selected according to IAEA creteria and received 153SmEDTMP in dosage of 37 GBq/g or 18.5 GBq/g. The efficacy and the sideeffects are evaluated in the following 16 weeks. Improvement of symptom, general condition and change of analgestic concumption are carefully recorded, so are the Lab findings. Seven patients died before the end of the study. In the rest 73 cases, 63 cases show the evidence of palliation, the total response rate after single dose of 153Sm EDTMP is 86.3%. The effect persisted for 8.2±4.5 weeks. Nearly 50% of the cases have blood count drops, 10 cases have the evidence of liver damage. All sideeffects disappeared after 6-8 weeks. 9 of 10 nonresponding cases are male, 6 of them suffer from lung cancer. In conclusion, single injection of  153SmEDTMP is effective in treating painful bone metastases, the efficacy and sideeffects are both dosageindependents; male or lung cancer might bear higher risk of being not responding to the therapy. A deeply insighted study is justified for further verification of 153SmEDTMP palliative therapy. Key words\ 153 Sm EDTMP\ metastases\ bone pain\ efficacy