153Sm-EDTMP治疗多发骨转移瘤的剂量效应关系初步观察

背景与目的:核素内照射治疗的剂量计算一直是核医学研究的热点和难点之一,用蒙特卡罗法(MonteCarlo,MC)计算153Sm-乙二胺四甲撑膦酸(Samarium-153ethylenediaminetetramethylenephosphonicacid,153Sm-EDTMP)治疗多发性骨转移患者骨转移灶、骨髓等靶器官的吸收剂量,初步探讨病灶吸收剂量与153Sm-EDTMP止痛疗效的关系。方法:选择鼻咽癌、乳腺癌伴全身多发骨转移患者4例,患者骨痛剧烈,骨痛评分Ⅳ级,按0.65×37MBq/kg药量静脉注射,行153Sm-EDTMP内照射治疗。基于患者的时序性SPECT/CT扫描和累积尿液的放射性强度测定,确定患者的药物代谢动力学特点,利用MCEGS4程序计算骨转移灶和其它靶器官的吸收剂量及其分布。观察骨痛症状的缓解状况和生活质量的改善情况。结果:153Sm-EDTMP治疗后,患者骨痛明显减轻,骨痛评分达Ⅱ级,持续3～4周。骨转移灶和其它靶器官的三维吸收剂量分布图显示:病灶内剂量分布不均匀。骨转移灶的最高吸收剂量约为4.9～5.9Gy,病灶边缘的吸收剂量为2.0Gy左右,以病灶区最高剂量为参考点,则骨髓剂量为0.48～1.1Gy,骨皮质剂量为0.51～0.85Gy;病灶周围软组织的吸收剂量为0.01～0.14Gy。结论:按常规单次153Sm-EDTMP治疗,骨转移病灶远未达到30Gy姑息剂量水平,虽有一定的止痛结果,但止痛持续时间短,疗效有限,与临床观察结果一致。

Primary investigation of dose-effect relationship of 153Sm-EDTMP in treating multiple bone metastases

BACKGROUND & OBJECTIVE: Dose calculation of radionuclide internal irradiation is a hot topic and difficulty of nuclear medical researches. This study was to calculate the focus absorption dose of 153Sm-EDTMP with the Monte Carlo EGS4 method for treatment of bone metastases from nasopharyngeal carcinoma or breast cancer, and investigate the relationship between the focus absorption dose and painkilling effect of 153Sm-EDTMP. METHODS: Four patients with multiple bone metastases from nasopharyngeal or breast carcinoma and suffered from grade IV bone pain were treated with radionuclide internal irradiation of 153Sm-EDTMP. The absorption dose and dose distribution of bone metastases and other targeted organs were calculated with MC EGS4 program based on the time-order SPECT/CT scanning and the measurement of the radioactivity in the urine accumulation. The release of bone pain and the improvement of life quality were observed. RESULTS: Bone pain of the patients was significantly alleviated to grade II for 3-4 weeks after internal 153Sm-EDTMP irradiation. The 3-dimensional absorption dose distribution image of bone metastases and targeted organs showed that the dose distribution in bone metastases was not asymmetrical. After injection of 0.65x37 MBq/kg 153Sm-EDTMP, the highest absorption dose in bone lesions was about 4.9-5.9 Gy, and the dose in the lesion margin was about 2.0 Gy. Use the highest dose as reference dose point, the relative absorption dose values of bone marrow, bone cortex, and soft tissue near lesions were 0.48-1.1 Gy, 0.51-0.85 Gy, and 0.01-0.14 Gy, respectively. CONCLUSIONS: The absorption dose of bone metastases is significantly lower than treatment dose of 30 Gy after single irradiation of 153Sm-EDTMP. The painkilling effect is limited and in accordance with clinical observation.