一种用于细胞实验的新型α粒子照射装置的建造和验证

The building and validation of a novel α-irradiation equipment used for cultured cell study

整个装置由α粒子源、源支架和盖玻片盘等构成。根据理论推导可计算出样品中每个细胞接受到的α粒子数。利用Geant4程序包作为构建模型和模拟粒子输运的工具,还计算了盖玻片上细胞的剂量率分布,得出了盖玻片上离圆心不同距离处的剂量率分布图。最后,本研究还利用正常人皮肤成纤维细胞WS1,检测了用本照射仪照射细胞后30 min时的DNA双链断裂标记物-53BP1 foci的形成和照射后细胞的克隆生存曲线。结果显示,在盖玻片上不同位置处的细胞受照剂量存在差异,α粒子的剂量率与细胞与盖玻片圆心处的距离成反相关。与X-射线相比,α粒子造成的细胞死亡更严重,在SF为0.5时,其相对生物学效应RBE等于1.71。综合以上结果,本研究设计并建造的α粒子照射仪是一个制作成本较低、使用方便、剂量精确的照射装置,满足放射生物学中在细胞及分子水平上研究α粒子的生物学效应的需要。

The aim is to build a user-friendly α-irradiation equipment used for cultured cell study, and to validate its dosimetry and biological efficiency as well. The equipment is composed of α-particle source（241Am）, a holder for 241 Am, a holder plate for coverslips on which cells grow, and other essential parts. The theoretical average α-particle traversal per cell was calculated based on ideal assumptions. The Geant4 software package was used for modeling and simulating particle traversal. And the dose rate distribution in cells on coverslip was calculated and plotted versus the distance from the center of coverslip. Moreover, the induction of 53BP1 foci, a surrogate marker of DNA double strand breaks and colony formation in WS1 normal human skin fibroblasts irradiated with the α-irradiation equipment were determined. The results showed the disconformity of α-irradiation dose on the coverslip, with the farther the distance from the center of the coverslip, the lower the dose rate. The relative biological efficiency of α-irradiation（RBE） was 1.71 at a SF of 0.5. In conclusion, we have built a user-friendly α-irradiation equipment with a good automation system for cultured cell study, providing better accuracy of exposure time and dose.