Institute of Modern Physics, Fudan University, Shanghai 200433, China.
Key Laboratory of Nuclear Physics and Ion-beam Application (MOE), Fudan University, Shanghai 200433, China.
J Radiat Res. 2024 Sep 24;65(5):591-602. doi: 10.1093/jrr/rrae046.
A Monte Carlo simulation was used to assess the performance of a collimated hollow X-ray microbeam for subcellular cytoplasm irradiation. A high-Z coaxial collimation structure with an inner core for nucleus shielding was investigated. Two key performances, the extraction efficiency (cytoplasm dose per unit incident fluence) and the dose contrast (cytoplasm-to-nucleus dose ratio), were evaluated regarding the influences of the material, geometry and physical arrangements of the collimator, target dish and incident beam source. Simulation results demonstrate that a gold coaxial structure with a practical collimation geometry of a 1-mm length, 10-μm inner diameter and 200-μm outer diameter, with the top exit closely attached (with a minimized air gap) to the bottom of a cell dish with a 3-μm thick Mylar film is recommended for cytoplasm irradiation of adherent mammalian cells. For a synchrotron source in the energy range < 10 keV, a dose contrast of approximately 100 can be achieved. For a bremsstrahlung source <30-kV tube voltage, a dose contrast of approximately 50-100 can still be achieved. General principles are summarized with further explanations of the performance of the hollow X-ray microbeam.
采用蒙特卡罗模拟方法评估了用于亚细胞细胞质辐照的准直中空 X 射线微束的性能。研究了一种带有用于屏蔽核的内芯的高 Z 同轴准直结构。针对准直器、靶盘和入射束源的材料、几何形状和物理布置的影响，评估了两个关键性能，即提取效率（单位入射通量的细胞质剂量）和剂量对比度（细胞质与细胞核的剂量比）。模拟结果表明，对于贴壁哺乳动物细胞的细胞质辐照，推荐使用具有实际准直几何形状（长度为 1 毫米、内径为 10 微米、外径为 200 微米）的金同轴结构，其顶部出口与具有 3 微米厚聚酯薄膜的细胞盘的底部紧密贴合（最小化空气间隙）。对于能量范围 <10 keV 的同步加速器源，可以实现约 100 的剂量对比度。对于 <30 kV 管电压的韧致辐射源，仍可以实现约 50-100 的剂量对比度。总结了一般原则，并进一步解释了中空 X 射线微束的性能。
