Suman Shubhankar, Datta Kamal, Trani Daniela, Laiakis Evagelia C, Strawn Steven J, Fornace Albert J
Department of Biochemistry and Molecular & Cell Biology, Lombardi Comprehensive Cancer Center, Georgetown University, Room E504 Research Building, 3970 Reservoir Rd., NW, Washington, DC 20057-1468, USA.
Radiat Environ Biophys. 2012 Aug;51(3):303-9. doi: 10.1007/s00411-012-0418-9. Epub 2012 May 5.
Study of heavy ion radiation-induced effects on mice could provide insight into the human health risks of space radiation exposure. The purpose of the present study is to assess the relative biological effectiveness (RBE) of (12)C and (28)Si ion radiation, which has not been reported previously in the literature. Female C57BL/6J mice (n = 15) were irradiated using 4-8 Gy of (28)Si (300 MeV/nucleon energy; LET 70 keV/μm) and 5-8 Gy of (12)C (290 MeV/nucleon energy; LET 13 keV/μm) ions. Post-exposure, mice were monitored regularly, and their survival observed for 30 days. The LD(50/30) dose (the dose at which 50 % lethality occurred by 30-day post-exposure) was calculated from the survival curve and was used to determine the RBE of (28)Si and (12)C in relation to γ radiation. The LD(50/30) for (28)Si and (12)C ion is 5.17 and 7.34 Gy, respectively, and the RBE in relation to γ radiation (LD(50/30)-7.25 Gy) is 1.4 for (28)Si and 0.99 for (12)C. Determination of RBE of (28)Si and (12)C for survival in mice is not only important for space radiation risk estimate studies, but it also has implications for HZE radiation in cancer therapy.
对小鼠重离子辐射诱导效应的研究有助于深入了解太空辐射暴露对人类健康的风险。本研究的目的是评估¹²C和²⁸Si离子辐射的相对生物效应（RBE），此前文献中尚未有相关报道。使用4 - 8 Gy的²⁸Si（300 MeV/核子能量；传能线密度70 keV/μm）和5 - 8 Gy的¹²C（290 MeV/核子能量；传能线密度13 keV/μm）离子对15只雌性C57BL/6J小鼠进行辐照。辐照后，定期监测小鼠情况，并观察其30天的存活情况。根据存活曲线计算LD(50/30)剂量（辐照后30天出现50%致死率的剂量），并用于确定²⁸Si和¹²C相对于γ辐射的RBE。²⁸Si和¹²C离子的LD(50/30)分别为5.17 Gy和7.34 Gy，相对于γ辐射（LD(50/30) - 7.25 Gy）的RBE，²⁸Si为1.4，¹²C为0.99。确定²⁸Si和¹²C对小鼠存活的RBE不仅对太空辐射风险评估研究很重要，对癌症治疗中的高电荷态重离子（HZE）辐射也有影响。
