Relative biological effectiveness of 290 MeV/u carbon ions for the growth delay of a radioresistant murine fibrosarcoma.
Relative biological effectiveness of 290 MeV/u carbon ions for the growth delay of a radioresistant murine fibrosarcoma.
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290 MeV/u 碳离子对抗辐射鼠纤维肉瘤生长延迟的相对生物有效性。
DOI：
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发表时间：
2002
影响因子：
2
通讯作者：
H. Majima
中科院分区：
文献类型：
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作者：
S. Koike;K. Ando;C. Oohira;T. Fukawa;Ryonfa Lee;N. Takai;M. Monobe;Y. Furusawa;M. Aoki;S. Yamada;W. Shimizu;K. Nojima;H. Majima
本文研究了290 MeV/u碳离子分次剂量治疗动物肿瘤的相对生物学效应。研究了不同剂量的碳离子和铯γ射线对小鼠NFSa纤维肉瘤生长的延迟作用，并测定了RBE。用不同LET（线性能量转移）的碳离子在6 cm SOBP（展开布拉格峰）中照射动物肿瘤，并研究了等效剂量，即诱导肿瘤生长延迟15天所需的剂量。14和20 keV/microm的碳离子的等效应剂量随着馏分数的增加而增加，最多可达4个馏分。对于44 keV/microm的碳离子，等效应剂量随分数的增加很小，而对于74 keV/microm则没有观察到。用Fe-plot分析法计算辐射剂量-细胞存活关系的线性二次模型的α和β值。α值随LET的增加而线性增加，而β值与LET无关。γ射线的α/β比为129 +/- 10戈伊，并且随着LET的增加而增加，对于74 keV/microm碳离子达到475 +/- 168戈伊。碳离子相对于Cs-137 γ射线的RBE随LET的增加而增加。14和20 keV/microm的碳离子的RBE值为1.4和独立的馏分的数量，而那些为44和74 keV/microm的分别从1.8增加到2.3和从2.4增加到3.0，当馏分的数量从1增加到4。将分数的数量从4进一步增加到6与RBE的增加无关。这些结果与我们早期对皮肤反应的研究一起支持在80 keV/microm碳束的临床试验中使用RBE为3.0。还考虑了低剂量碳束的RBE值。
The relative biological effectiveness (RBE) for animal tumors treated with fractionated doses of 290 MeV/u carbon ions was studied. The growth delay of NFSa fibrosarcoma in mice was investigated following various daily doses given with carbon ions or those given with cesium gamma-rays, and the RBE was determined. Animal tumors were irradiated with carbon ions of various LET (linear energy transfer) in a 6-cm SOBP (spread-out Bragg peak), and the isoeffect doses; i.e. the dose necessary to induce a tumor growth delay of 15 days were studied. The iso-effect dose for carbon ions of 14 and 20 keV/microm increased with an increase in the number of fractions up to 4 fractions. The increase in the isoeffect dose with the fraction number was small for carbon ions of 44 keV/microm, and was not observed for 74 keV/microm. The alpha and beta values of the linear-quadratic model for the radiation dose-cell survival relationship were calculated by the Fe-plot analysis method. The alpha values increased linearly with an increase in the LET, while the beta values were independent of the LET. The alpha/beta ratio was 129 +/- 10 Gy for gamma-rays, and increased with an increase in the LET, reaching 475 +/- 168 Gy for 74 keV/microm carbon ions. The RBE for carbon ions relative to Cs-137 gamma-rays increased with the LET. The RBE values for 14 and 20 keV/microm carbon ions were 1.4 and independent of the number of fractions, while those for 44 and 74 keV/microm increased from 1.8 to 2.3 and from 2.4 to 3.0, respectively, when the number of fractions increased from 1 to 4. Increasing the number of fractions further from 4 to 6 was not associated with an increase in the RBE. These results together with our earlier study on the skin reaction support the use of an RBE of 3.0 in clinical trials of 80 keV/microm carbon beams. The RBE values for low doses of carbon beams were also considered.