100 MeV质子束流品质诊断及剂量测量准确性评估方法研究

质子辐射生物学效应是太空放射生物学和质子束放疗研究的重要基础，可为空间环境下人员的危险性评估以及质子治疗优化设计提供科学依据。依托加速器建立相应的生物样本辐照技术是开展此类研究的前提条件。中国原子能科学研究院最近建立的100 MeV强流质子回旋加速器提供的中能质子束流为目前国内能量最高，特别适合用于太空放射生物学和质子治疗相关研究。本研究中，利用在束和离线等多种手段建立了中能质子束流诊断和剂量测量方法，对加速器引出的100 MeV质子照射野大小、均匀性等束流品质以及剂量测量系统准确性进行了分析和评估。结果表明，对光子剂量响应好的LiF(Mg, Ti)热释光探测器，对90 MeV质子同样具有良好的剂量响应关系，可作为中能质子剂量准确性评估的手段之一。在5.0 cm×5.0 cm照射野范围内，加速器引出的100 MeV质子束流的均匀性好于90%，在线剂量测量系统准确性好于93%，束流品质和剂量测量条件基本满足辐射生物学的要求，可为质子辐射生物学效应研究的开展提供可靠保障。     

不同LET辐射致DNA集簇性损伤的研究

利用辐照质粒DNA构象变化的分子模型,以DNA糖苷酶Fpg和AP核酸内切酶EndoIII识别并切割辐射所致DNA碱基损伤,将其转换为DNA断裂损伤,通过电泳分析DNA分子构象变化,研究比较γ射线、质子和7Li离子诱发DNA集簇性损伤。50Gy以上高剂量γ辐射对质粒DNA的损伤主要表现为单链断裂(SSB)和很少比例的双链断裂(DSB),并能产生一定水平的集簇性损伤。相比之下,高能质子束和高LET的7Li离子直接所致DNA的断裂损伤以及所产生的集簇性碱基损伤比γ射线的要严重,质子10Gy照射就可诱发明显的集簇损伤。     

Supplementary Material: A Dynamic Model of Heavy Ion ~7Li Irradiation Mutagenesis Based on Maize Inbred Line Nutrition Difference

正Text A:Irradiation mutagenesis Heavy ion ~7Li radiation mutagenesis was performed by the HI-13 tandem accelerator at the China Institute of Atomic Energy.The radiation procedure was configured as previously described,with a     

α-Si1-xCx:H薄膜材料的弹性反冲探测分析

介绍在中国原子能科学研究院HI-13串列加速器上，对α-Si1-xCx:H薄膜样品进行弹性反冲探测分析的方法和结果．用该加速器提供的高品质^127Ⅰ束流轰击α-Si1-xCx:H薄膜材料样品，用△E(gas)一E(PSD)望远镜探测器，在前角区(30。角)测量从该样品中反冲的各元素的能谱．然后用离子束分析(IBA)程序SIMNRA对能谱进行拟合，得到样品中H，C和Si的比分及深度分布．Elastic recoil detection analysis of α-Si_(1-x)C_(x)∶H foils has been performed at the HI-13 tandem accelerator of CIAE. High quality~(127)I beam bombards the target of α -Si_(1-x)C_(x)∶H_( ) thin film. A ΔE(gas)-(E(PSD)) telescope was used to measure the energy spectra of all elements recoiled from the samples at the angle of 30° in laboratory system. Components of H, C and Si and the profiles were obtained by simulation of the energy spectra using the program SIMNRA calculation.     

Atomic Force Microscopy Measurement of DNA Fragment Induced by Heavy Ions

Choosing ^7 Li and ^12C heavy ions respectively with different linear energy transfer (LET) values, purified plasmid DNA samples in aqueous solution are irradiated with various doses. The atomic force microscopy (AFM) is used for analysis of DNA fragments induced by both the kinds of heavy ions. There is a change of three forms of DNA, i.e. supercoiled, open circular and linear form, as the dose is observed. The distribution function of DNA fragment length is obtained for the first time and fitted with the Tsallis entropy statistical theory. The result indicates that AFM is a useful tool for analysis of the short fragment of DNA, high-LET heavy ion radiation induces DNA double strand breaks (DSBs) more effectively, and the distributions of the DSBs are more local and dense in comparison with low-LET radiation.     

质子照射小鼠组织病理损伤的初步观察

利用HI-13串列加速器提供的19 MeV 质子照射麻醉小鼠2, 4, 8和16 Gy ， 照射后不同时间麻醉处死小鼠进行病理组织学观察。 结果显示， 照射后各组小鼠腰背部开始环状脱毛， 病理改变为表皮细胞坏死、 脱落， 皮下水肿， 心、 肝出现小灶性坏死或伴出血， 肝细胞明显再生， 肺组织可出现充血及肺泡间隔明显增厚， 肾小球出现明显固缩、 坏死及消失。 这些病理改变在大剂量照射组尤为明显。 通过观察质子照射小鼠组织病理损伤效应， 为质子损伤的防治研究提供参考依据。Space radiation come from galactic cosmic rays and solar particle events which contain considerable protons is an invisible killer to astronauts. Furthermore， many wounded persons were injured by proton and other heavy ion radiation in a nuclear warhead or nuclear terrorism attack. However， the damage effect of proton radiation is known little in our country. In this study， the proton induced histopathologic changes of mice were observed primarily. naesthetic mice were irradiated with the 19 MeV protons dili vered by HI 13 tandem accelerator at CIAE in different doses(2， 4， 8， 16 Gy). In order to observe the da mage effect， mice were killed by anaesthetic at different time point after radiation， and the tissue sections were analyzed by a histopathologic method. The results show that all of the mice’s backs began displaying ringed depilation at post irradiation day 7. Many epidermal cells necrosis and exfoliation happened， and subcutaneous dropsy was observed. There were some focal necrosis or even followed with bleeding in heart and liver. Hepatocyte evidently regenerated. A hyperaemia was seen in lung tissue and alveolar septum was obviously thickening. Acinus renis represented notable pyknosis， necrosis and disappearance. Especially， these pathologic alteration clearly displayed in high dose groups. In conclusion， proton radiation can induce different grade injury to skin， heart， liver， lung， kidney and other organs. Further studies should be made to deeply understand the mechanism about the proton radiation damage.     

7Li和12C离子致DNA链断裂的研究

选用HI-13串列加速器产生的不同传能线密度的⁷Li和¹²C重离子,以不同的剂量对纯化的质粒DNA水溶液进行了辐照.利用原子力显微镜对这两种重离子诱发的DNA损伤进行了纳米水平的结构分析,并用ScionImage分析软件完成了DNA碎片长度的测量.得到了DNA分子超螺旋、开环和线性三种形态随剂量的变化情况以及DNA碎片长度的分布函数,并用Tsallis熵统计理论对实验结果进行了拟合.     

α-Si_(1-x)C_x∶H薄膜材料的弹性反冲探测分析

介绍在中国原子能科学研究院HI 13串列加速器上,对α Si1-xCx∶H薄膜样品进行弹性反冲探测分析的方法和结果.用该加速器提供的高品质127I束流轰击α Si1-xCx∶H薄膜材料样品,用ΔE(gas) E(PSD)望远镜探测器,在前角区(30°角)测量从该样品中反冲的各元素的能谱.然后用离子束分析(IBA)程序SIMNRA对能谱进行拟合,得到样品中H,C和Si的比分及深度分布.     

重离子辐照玉米种子M1代诱变效应研究

用重离子^7Li和^12C以及^60Co的γ射线分别辐照玉米种子胚，研究重离子束辐照玉米种子M1代的生物学效应．结果表明:^60Co的丫射线使种子的发芽势和发芽率降低，重离子^7Li和^12C对发芽势和发芽率的抑制作用不明显；重离子辐照后，单株之间光合速率差异增大；M1代植株在雄性育性、叶片颜色及株高等方面发生了多种变化，并产生了一株双胚苗．应用随机多态性DNA分析技术，发现双胚苗的大、小苗之间及其与亲本自交系478在随机多态性DNA指纹上存在的差异，从分子水平上初步证实了双胚苗为自交系478的变异类型．In order to study M_(1) biological effects of heavy ion irradiation on maize seeds, the embryos of dry maize seeds are irradiated with~(7)Li ions and~(12)C ions as well as ~( 60)Co gamma rays. The results are as follows: ~( 60)Co gamma rays decrease germination impetus and germination rate of maize seeds, while the inhibitory effects of germination impetus and germination rate induced by the heavy ions~(7)Li and~(12)C are not significant. The difference of photosynthetic rates among the plants irradiate...     

γ射线诱导DNA损伤中DNA浓度和剂量率的影响

在进行辐射致DNA损伤中, DNA浓度和剂量率是两个重要的因素。 利用γ射线在不同的剂量率下对不同浓度的质粒DNA pUC19水溶液进行了辐照， 利用凝胶电泳对辐照后的样品进行分析。 结果表明， 在同一剂量下被辐照的DNA样品， 随浓度的降低DNA损伤越来越严重； 通过分析软件和理论公式得到的每个DNA上的双链断裂数随着DNA浓度的变化呈现为非线性趋势。 As two factors， the changes of concentration of DNA and dose rate are of significance in the study of DNA damage induced by irradiation. The influence of DNA damage induced by γ ray at different concentration of DNA under different dose rate was investigated. The result of gel electrophoresis indicate that DNA molecules were damaged severely as the concentration of DNA decreasing. The number of double strand breakages per DNA were obtained by the software of Alpha Innotech and theoretical analysis. It shows that the numbers of double strand breakages per DNA presented nonlinear feature as the concentration of DNA decreasing, and the dose rate had little influence on DNA damage.