Kaminaga Kiichi, Fukunaga Hisanori, Hirose Eri, Watanabe Ritsuko, Suzuki Keiji, Prise Kevin M, Yokoya Akinari
Institute for Quantum Life Science, National Institutes for Quantum Science and Technology, 4-9-1 Anagawa, Inage, Chiba 263-8555, Japan.
Faculty of Health Sciences, Hokkaido University, N12 W5 Kita-ku, Sapporo 060-0812, Japan.
J Radiat Res. 2025 May 23;66(3):318-328. doi: 10.1093/jrr/rraf020.
Due to the limited number of accelerator-based X-ray facilities worldwide that provide beams with an adjustable size, their application for radiobiological research purposes has been restricted. Thus, the development of alternative methods is of technical importance for investigating cell/tissue responses in spatially non-uniform radiation fields. In this study, we performed mini beam irradiation of cells using a lead (Pb) sub-milli-collimator as an alternative method to sub-millimeter beams. Also, we employed human cervical carcinoma HeLa cells and hTERT-immortalized fibroblast BJ-1 cells that express fluorescence ubiquitination-based cell-cycle indicators (FUCCI). Time-lapse imaging revealed differences in the behavior of HeLa and BJ-1 cells in spatially heterogeneous radiation fields; in the case of HeLa cells, G2/M phase-arrested cells in the cell population were clearly observed, distinguishing irradiated from non-irradiated cells at the sub-millimeter scale level. Our findings indicate that FUCCI can be useful as a biological dose indicator, depending on cell type, and Pb sub-milli-collimators show potential as a possible alternative to accelerator-based X-ray sub-millimeter beams for radiobiological research. The use of the collimators, unlike beamtime experiments in synchrotron facilities with the approval of the committee, is highly versatile and may be beneficial in preliminary studies in a normal laboratory environment.
由于全球范围内基于加速器的X射线设施数量有限，这些设施提供的光束尺寸可调，其在放射生物学研究中的应用受到了限制。因此，开发替代方法对于研究空间非均匀辐射场中的细胞/组织反应具有重要的技术意义。在本研究中，我们使用铅（Pb）亚毫米准直器对细胞进行微束照射，作为亚毫米光束的替代方法。此外，我们使用了表达基于荧光泛素化的细胞周期指示剂（FUCCI）的人宫颈癌HeLa细胞和hTERT永生化成纤维细胞BJ-1细胞。延时成像揭示了HeLa细胞和BJ-1细胞在空间异质辐射场中的行为差异；在HeLa细胞的情况下，在细胞群体中清楚地观察到G2/M期停滞的细胞，在亚毫米尺度水平上区分了照射细胞和未照射细胞。我们的研究结果表明，根据细胞类型，FUCCI可作为一种生物剂量指示剂，并且铅亚毫米准直器显示出作为基于加速器的X射线亚毫米光束用于放射生物学研究的可能替代方案的潜力。与需要委员会批准的同步加速器设施中的束流时间实验不同，准直器的使用具有高度的通用性，可能有利于在正常实验室环境中的初步研究。
