[Primary investigation of dose-effect relationship of 153Sm-EDTMP in treating multiple bone metastases].
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.
Fan
Wei
W
State Key Laboratory of Oncology in South China, Guangzhou, Guangdong, 510060, P. R. China. jimfanwei@163.com
Chen
Li-Xin
LX
Liu
Xiao-Wei
XW
Tang
Qiang
Q
Wang
Guo-Hui
GH
Zhi
Sheng-Fang
SF
Zeng
Zong-Yuan
ZY
D000328:Adult; D018712:Analgesics, Non-Narcotic / Q000008:administration & dosage; D001859:Bone Neoplasms / Q000532:radiotherapy / Q000556:secondary*; D001943:Breast Neoplasms / Q000473:pathology*; D004307:Dose-Response Relationship, Radiation; D005260:Female; D006801:Humans; D008875:Middle Aged; D009010:Monte Carlo Method; D009303:Nasopharyngeal Neoplasms / Q000473:pathology*; D009942:Organometallic Compounds / Q000008:administration & dosage* / Q000627:therapeutic use; D009943:Organophosphorus Compounds / Q000008:administration & dosage* / Q000627:therapeutic use; D010146:Pain / Q000209:etiology / Q000532:radiotherapy*; D010147:Pain Measurement; D011868:Radioisotopes / Q000008:administration & dosage; D012493:Samarium / Q000008:administration & dosage
D018712:Analgesics, Non-Narcotic; D009942:Organometallic Compounds; D009943:Organophosphorus Compounds; D011868:Radioisotopes; D012493:Samarium; C061972:samarium Sm-153 lexidronam