Wojcik A, Obe G, Lisowska H, Czub J, Nievaart V, Moss R, Huiskamp R, Sauerwein W
CRPR, GMT Department, Stockholm University, Sweden.
J Radiol Prot. 2012 Sep;32(3):261-75. doi: 10.1088/0952-4746/32/3/261. Epub 2012 Jul 19.
Cells exposed to thermal neutrons are simultaneously damaged by radiations with high and low linear energy transfer (LET). A question relevant for the assessment of risk of exposure to a mixed beam is whether the biological effect of both radiation types is additive or synergistic. The aim of the present investigation was to calculate whether the high and low LET components of a thermal neutron field interact when damaging cells. Human peripheral blood lymphocytes were exposed to neutrons from the HB11 beam at the Institute for Energy and Transport, Petten, Netherlands, in a 37 °C water phantom at varying depths, where the mix of high and low LET beam components differs. Chromosomal aberrations were analysed and the relative biological effectiveness (RBE) values as well as the expected contributions of protons and photons to the aberration yield were calculated based on a dose response of aberrations in lymphocytes exposed to (60)Co gamma radiation. The RBE for 10 dicentrics per 100 cells was 3 for mixed beam and 7.2 for protons. For 20 dicentrics per 100 cells the respective values were 2.4 and 5.8. Within the limitations of the experimental setup the results indicate that for this endpoint there is no synergism between the high and low LET radiations.
暴露于热中子的细胞会同时受到高、低传能线密度（LET）辐射的损伤。一个与评估混合束照射风险相关的问题是，这两种辐射类型的生物学效应是相加的还是协同的。本研究的目的是计算热中子场的高、低LET成分在损伤细胞时是否相互作用。在荷兰佩滕的能源与运输研究所，将人类外周血淋巴细胞置于37°C的水体模中，在不同深度处暴露于HB11束的中子，在这些深度处，高、低LET束成分的混合情况不同。分析染色体畸变，并根据暴露于（60）Coγ辐射的淋巴细胞中畸变的剂量反应，计算相对生物效能（RBE）值以及质子和光子对畸变产额的预期贡献。每100个细胞中有10个双着丝粒时，混合束的RBE为3，质子的RBE为7.2。每100个细胞中有20个双着丝粒时，相应的值分别为2.4和5.8。在实验设置的限制范围内，结果表明，对于这个终点，高、低LET辐射之间没有协同作用。
