Monte Carlo track-structure for the radionuclide Copper-64: characterization of S-values, nanodosimetry and quantification of direct damage to DNA.
Monte Carlo track-structure for the radionuclide Copper-64: characterization of S-values, nanodosimetry and quantification of direct damage to DNA.
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DOI：
10.1088/1361-6560/ab8aaa
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发表时间：
2020-07-27
影响因子：
3.5
通讯作者：
Ávila-Rodríguez MA
中科院分区：
文献类型：
--
作者：
Carrasco-Hernández J;Ramos-Méndez J;Faddegon B;Jalilian AR;Moranchel M;Ávila-Rodríguez MA
TOPAS-nBio 用于模拟 64Cu 衰变显式模拟过程中产生的电子在水中的碰撞到碰撞的完整轨迹。计算代表半径分别为 5 μm 和 4 μm 的同心球的细胞 (C) 和细胞核 (N) 的 S 值和对 DNA 的直接损伤。考虑的“靶”←“源”构型，包括细胞表面 (Cs) 和细胞质 (Cy)，为：C←C、C←Cs、N←N、N←Cy 和 N←Cs。还计算了浸入水中的圆柱体中的电离簇尺寸分布，该圆柱体对应于长度为 10 个碱基对的 DNA 片段（直径 2.3 nm，长度 3.4 nm），模拟从圆柱体中心轴移动到边缘的放射性点源。为此，获得了圆柱体积中具有 2 个或更多电离团簇大小的一阶矩 (M1) 和累积概率 (F2)。最后，通过使用聚类算法 DBSCAN 量化双链断裂 (DSB) 来估计对 DNA 的直接损伤。 64Cu 的 TOPAS-nBio 获得的 S 值为 7.879×10−4±5×10−7、4.351×10−4±6×10−7、1.442×10−3±1×10−6、2.596×10−4±8×10−7、1.127×10−4±4×10−7 Gy/Bq-s 分别对应构型 C←C、C←Cs、N←N、N←Cy 和 N←Cs。与之前报道的使用代码 MNCP 和软件 MIRDCell 的 64Cu 的 S 值相比，这些值的差异对于 N←N 和 N←Cs 的配置分别为 -4% 到 -25%。另一方面，光源位于圆柱体中心时，F2 最大，为 0.373±0.001，并单调下降，直到在 2.3 nm 处达到 0.058±0.001 的值。 M1 也观察到相同的行为，其值范围为 2.188±0.004 至 0.242±0.002。最后，DBSCAN 算法显示，对于 N←N、N←Cs 和 N←Cy 配置，每次衰变的 DNA DSB 平均数量分别为 0.187±0.001、0.0317±0.0005 和 0.0125±0.0002 DSB-(Bq-s)−1。总之，S 值的结果表明，吸收剂量很大程度上取决于细胞中放射性核素的分布，当 64Cu 内化到细胞核中时，剂量更高，纳米剂量研究通过 64Cu 衰变过程中发射的俄歇电子产生的 DNA DSB 的存在强化了这一点。
TOPAS-nBio was used to simulate, collision-to-collision, the complete trajectories of electrons in water generated during the explicit simulation of 64Cu decay. S-values and direct damage to the DNA were calculated representing the cell (C) and the cell nucleus (N) with concentric spheres of 5 μm and 4 μm in radius, respectively. The considered “target”←“source” configurations, including the cell surface (Cs) and cytoplasm (Cy), were: C←C, C←Cs, N←N, N←Cy and N←Cs. Ionization cluster size distributions were also calculated in a cylinder immersed in water corresponding to a DNA segment of 10 base-pairs in length (diameter 2.3 nm, length 3.4 nm), modeling a radioactive point source moving from the central axis to the edge of the cylinder. For that, the first moment (M1) and cumulative probability of having a cluster size of 2 or more ionizations in the cylindrical volume (F2) were obtained. Finally, the direct damage to the DNA was estimated by quantifying double-strand breaks (DSBs) using the clustering algorithm DBSCAN. The S-values obtained with TOPAS-nBio for 64Cu were 7.879×10−4±5×10−7, 4.351×10−4±6×10−7, 1.442×10−3±1×10−6, 2.596×10−4±8×10−7, 1.127×10−4±4×10−7 Gy/Bq-s for the configurations C←C, C←Cs, N←N, N←Cy and N←Cs, respectively. The difference of these values, compared with previously reported S-values for 64Cu with the code MNCP and software MIRDCell, ranged from −4% to −25% for the configurations N←N and N←Cs, respectively. On the other hand, F2 was maximum with the source at the center of the cylinder 0.373±0.001, and monotonically decreased until reaching a value of 0.058±0.001 at 2.3 nm. The same behavior was observed for M1 with values ranging from 2.188±0.004 to 0.242±0.002. Finally, the DBSCAN algorithm showed that the mean number of DNA DSBs per decay were 0.187±0.001, 0.0317±0.0005, and 0.0125±0.0002 DSB-(Bq-s)−1 for the configurations N←N, N←Cs, and N←Cy, respectively. In conclusion, the results of the S-values show that the absorbed dose strongly depends on the distribution of the radionuclide in the cell, the dose being higher when 64Cu is internalized in the cell nucleus, which is reinforced by the nanodosimetric study by the presence of DNA DSBs attributable to the Auger electrons emitted during the decay of 64Cu.
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DOI：
10.3390/antiox5030025
发表时间：
2016-07-27
期刊：
Antioxidants (Basel, Switzerland)
影响因子：
--
作者：
Hatori Y;Lutsenko S
通讯作者：
Lutsenko S
影响因子：
3.4
作者：
Bodei, L;Kassis, AI;Mariani, G
通讯作者：
Mariani, G
影响因子：
3
作者：
Beaino, Wissam;Guo, Yunjun;Anderson, Carolyn J.
通讯作者：
Anderson, Carolyn J.
影响因子：
4.6
作者：
Guerreiro, Joana Fernandes;Alves, Vitor;Mendes, Filipa
通讯作者：
Mendes, Filipa
影响因子：
1.8
作者：
Hauf, Steffen;Kuster, Markus;Zoglauer, Andreas
通讯作者：
Zoglauer, Andreas