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  • 国产高剂量率近距离治疗Ir-192源剂量学参数模拟研究

    分类: 化学 >> 核化学 提交时间: 2024-06-07

    摘要: 背景 Ir-192近距治疗源是一种高剂量率γ射线放射源,其具有中心剂量率高且边缘剂量迅速下降的特性。在临床治疗过程中,这种剂量分布特性使得Ir-192放射源能够有效地保护肿瘤周围的正常组织和器官。目的 参考美国医学物理师协会(AAPM)在TG43-U1中推荐的Ir-192源的剂量学参数,基于蒙特卡罗模拟软件,建立国产高剂量率近距离治疗Ir-192放射源的精细结构模型,进行模拟计算。方法 使用蒙特卡罗软件建立国产高剂量率近距离治疗Ir-192放射源的精细结构模型,模拟计算剂量学参数,其中包括:剂量率常数Λ、单位活度空气比释动能强度、径向剂量函数以及各向异性函数。结果 模拟计算得到的剂量率常数为1.105 cGy·h-1·U-1,与文献报告的差异在1.2%以内;单位活度空气比释动能率为9.788×10-8 UBq-1,与文献报道结果的差异为0.23%。在放射源中垂线0.5至20厘米范围内得到了径向剂量函数,并拟合得到经验公式。结论 基于蒙特卡罗软件建立的国产Ir-192放射源模型,在剂量学参数上与文献报告的数据具有较好一致性,表明该模型可以用于国产Ir-192源的临床实践应用,具有一定的指导意义。

  • 18F标记HER2模拟肽显像剂的microPET显像及生物分布

    分类: 化学 >> 核化学 提交时间: 2024-05-02

    摘要: 背景:人表皮生长因子受体2(HER2)广泛存在于多种恶性肿瘤,且与预后不良有关。尤其在乳腺癌中,但HER2表达存在异质性,目前常用免疫组织化学和荧光原位杂交在评估HER2状态存在明显局限性。HER2受体显像有明显优势。放射性标记的模拟肽是检测HER2阳性病变的潜在选择。目的:制备一种18F标记的人表皮生长因子受体2(HER2)模拟肽显像剂18F-NFP-B2-S22-AFA(以下简称为18F-NFP-TP1296),探讨其microPET显像及生物分布。方法 采用一步法标记18F-NFP-TP1296被应用于HER2乳腺癌异种移植小鼠的PET-CT成像。在SKBR-3乳腺癌模型中进行了体外研究和MicroPET成像。结果18F-NFP-TP1296制备过程大约30分钟内完成,总标记率为1.5%,放化纯>95%。MicroPET成像显示,SKBR-3异种肿瘤清晰可见,注射30、60和120min后,SKBR-3移植瘤摄取值分别为5.63±0.14%ID/g、6.26±0.27%ID/g和5.83±0.44%ID/g。30、60和120min肿瘤与血液和肿瘤与肌肉的比率分别为3.21±0.32、4.08±0.73和1.69±0.18;1.55±0.11、1.84±0.12和3.10±0.30。另外肺转移瘤注射后30、60和120min肿瘤的摄取值2.2%ID/g、2.5%ID/g及2.1%ID/g。结论:18F-NFP-B2-S22-AFA具有合成简便、药代动力学良好等优点,有望成为体内检测HER2状态的示踪剂,对肿瘤的鉴别诊断、分子靶向治疗及预后判断有一定的参考价值。

  • 基于排放总量控制的核医学衰变池容量及最小暂存时间计算

    分类: 化学 >> 核化学 提交时间: 2024-04-09

    摘要: 近年来,在核医学科建设加速发展过程中,含碘-131放射性废水暂存时间、衰变池建设等成为医院、环评机构、生态环境监管部门等十分关心的问题。《电离辐射防护与辐射源安全基本标准》(GB 18871)、《核医学辐射防护与安全要求》(HJ 1188)、《关于核医学标准相关条款咨询问题的回函》规定了衰变池中放射性废水(主要核素为碘-131)的合规排放方式。本文通过理论推导,给出了在满负荷情况下、衰变池存满时碘-131活度的理论计算公式;证明了含碘-131放射性废水三种合规的排放方式中,按GB 18871规定的排放方式排放对医院核医学科运营最为有利;提出了RJ方程组,解决了含碘-131放射性废水最小暂存时间和衰变池容量应如何确定的问题。4家医院的实际监测数据结果表明,含碘-131放射性废水暂存时间达到RJ方程组计算出的最小暂存时间后,总的碘-131排放量符合国家生态环境标准要求。以上可对医院核医学科衰变池建设、废水排放管理以及监管部门的监督检查提供明确、具体的指导。

  • Branched Fibrous Amidoxime Adsorbent with Ultrafast Adsorption Rate and High Amidoxime Utilization for Uranium Extraction from Seawater

    分类: 化学 >> 核化学 提交时间: 2023-06-13

    摘要: Objective: We herein fabricated a branched structure containing AO groups on polypropylene/polyethylene spun-laced nonwoven (PP/PE SNW) fibers using grafting polymerization induced by radiation (RIGP) to improve AO utilization. Methods: The chemical structures, thermal properties, and surface morphologies of the raw and treated PP/PE SNW fibers were studied. The adsorption properties were investigated using batch adsorption experiments in simulated seawater with an initial uranium concentration of 500 gL-1 (pH 4, 25℃). Results: The maximum adsorption capacity of the adsorbent material was 137.3 mgg-1 within 24 h; moreover, the uranyl removal reached 96% within 240 min. Limitations: Only simulated seawater adsorption experiments have been conducted, and real seawater adsorption experiments are yet to be conducted. Conclusions: The adsorbent had an AO utilization rate of 1/3.5 and was stable over a pH range of 410, with good selectivity and reusability, demonstrating its potential for seawater uranium extraction.

  • Effect of radiolysis of TODGA on the extraction of TODGA/n-dodecane toward Eu(III): An experimental and DFT study

    分类: 化学 >> 核化学 提交时间: 2023-06-06

    摘要: N,N,N,N-Tetraoctyl diglycolamide (TODGA) is one of the most promising extractants tailored for high-level liquid radioactive waste treatment during nuclear fuel reprocessing. The -radiolysis of TODGA (0.2 mol/L) in n-dodecane (nDD) solution with and without pre-equilibrated 3.0 mol/L HNO3 was investigated using HPLC and UPLC-QTOF-MS and compared with the -radiolysis of neat TODGA in this study. With increased absorbed doses, the concentration of TODGA decreased exponentially for the studied systems. Moreover, pre-equilibration with HNO3 (3.0 mol/L) slightly influenced the -radiolysis of TODGA in nDD. Seven radiolytic products generated from the rupture of the C C, C O, and C N bonds in TODGA were identified in the studied extraction system. The influence of -radiation on TODGA/nDD for the extraction of Eu(III) was evaluated using the first combination of extraction experiments and density functional theory (DFT) calculations, in which the complexations of Eu(III) with TODGA and its radiolytic products were systematically compared. Based on the radiolysis kinetic model of TODGA, the slope curve of the distribution ratio of Eu(III) (DEu ) and the absorbed dose, and fluorescence titration analysis, the empirical equation of the absorbed dose and DEu was obtained successfully. Below 300 kGy, the experimental DEu agreed well with the obtained empirical equation for TODGA/nDD. Conversely, at a high absorbed dose, the experimental DEu was higher than the theoretical DEu based on the empirical equation because the radiolytic products of TODGA with similar coordination structures still possessed partial complexation toward Eu(III), which was confirmed by DFT calculations. This work provides a method to predict the extraction distribution ratio of an irradiated extractant system and to understand the complex extraction process.

  • Efficient extraction of U(VI) ions from solutions

    分类: 化学 >> 核化学 提交时间: 2023-05-31

    摘要: The rapid development of advanced techniques for selective and efficient U(VI) extraction from aqueous solutions is essential for addressing U(VI) environmental pollution and energy issues. Here, we share recent progress in U(VI) extraction from aqueous solutions, especially the most frequently applied techniques such as adsorption, catalysis (photocatalysis, piezocatalysis, and electrocatalysis), chemical deposition, and reduction by zero-valent metal particles. We attempt toelucidate the strategies and various mechanisms that contribute to the enhancement of selective U(VI) extraction. At the end of our review, we highlight the outlook, challenges, and prospects for the development of this field.

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