Abstract

Purpose

The objective of this research was to explore the dose-effect relationships of dicentric plus ring (dic + r), micronucleus (MN) and nucleoplasmic bridges (NPB) induced by carbon ions in human lymphocytes.

Materials and methods

Venous blood samples were collected from three healthy donors. ¹²C⁶⁺ ions beam was used to irradiate the blood samples at the energy of 330 MeV and linear energy transfer (LET) of 50 keV/μm with a dose rate of 1 Gy/min in the spread-out Bragg peak. The irradiated doses were 0 (sham irradiation), 1, 2, 3, 4, 5 and 6 Gy. Dic + r chromosomes aberrations were scored in metaphases. The cytokinesis-block micronucleus cytome (CBMN) was conducted to analyze MN and NPB. The maximum low-dose relative biological effectiveness (RBE_M) values of the induction of dic + r, MN and NPB in human lymphocytes for ¹²C⁶⁺ ions irradiation was calculated relative to ⁶⁰Co γ-rays.

Results

The frequencies of dic + r, MN and NPB showed significantly increases in a dose-depended manner after exposure to ¹²C⁶⁺ ions. The distributions of dic + r and MN exhibited overdispersion, while the distribution of NPB agreed with Poisson distribution at all doses. Linear-quadratic equations were established based on the frequencies of dic + r and MN. The dose-response curves of NPB frequencies followed a linear model. The derived RBE_M values for dic + r, MN and NPB in human lymphocytes irradiated with ¹²C⁶⁺ ions were 8.07 ± 2.73, 2.69 ± 0.20 and 4.00 ± 2.69 in comparison with ⁶⁰Co γ-rays.

Conclusion

The dose-response curves of carbon ions-induced dic + r, MN and NPB were constructed. These results could be helpful to improve radiation risk assessment and dose estimation after exposed to carbon ions irradiation.

中文翻译：

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12C6+离子诱导的体外人淋巴细胞双着丝粒加环染色体、微核和核质桥的量效关系

摘要

目的

本研究的目的是探讨碳离子在人淋巴细胞中诱导的双着丝粒加环 (dic + r)、微核 (MN) 和核质桥 (NPB) 的剂量效应关系。

材料和方法

从三名健康供体收集静脉血样本。¹² C ⁶⁺离子束用于以330 MeV的能量和50 keV/μm的线性能量转移(LET)以1 Gy/min的剂量率在展开的布拉格峰照射血样。照射剂量为 0（假照射）、1、2、3、4、5 和 6 Gy。Dic + r 染色体畸变在中期评分。进行胞质分裂阻断微核细胞组 (CBMN) 以分析 MN 和 NPB。相对于⁶⁰ Co γ 射线，计算了¹² C ⁶⁺离子照射在人淋巴细胞中诱导 dic + r、MN 和 NPB的最大低剂量相对生物有效性 (RBE _M ) 值。

结果

dic + r、MN 和 NPB 的频率在暴露于¹² C ⁶⁺离子后以剂量依赖性方式显着增加。dic + r 和 MN 的分布表现出过度分散，而 NPB 的分布与所有剂量下的泊松分布一致。基于dic+r和MN的频率建立线性二次方程。NPB 频率的剂量反应曲线遵循线性模型。与⁶⁰ Co γ 射线相比，用¹² C ⁶⁺离子照射的人淋巴细胞中 dic + r、MN 和 NPB的衍生 RBE _M值为8.07 ± 2.73、2.69 ± 0.20 和 4.00 ± 2.69 。

结论

构建了碳离子诱导的dic+r、MN和NPB的剂量反应曲线。这些结果可能有助于改善暴露于碳离子辐照后的辐射风险评估和剂量估计。