Theoretical studies of the physical and chemical aspects of primary processes in fundamental radiobiology

基础放射生物学中初级过程的物理和化学方面的理论研究

• 批准号: RGPIN-2022-03972
• 负责人: JayGerin, JeanPaul
• 金额: $ 2.04万
• 依托单位: Université de Sherbrooke
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2022
• 资助国家: 加拿大
• 起止时间: 2022-01-01 至 2023-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=760618
• 关键词: Theoretical; studies; physical; chemical; aspects

Understanding radiation-induced processes in water is of crucial importance to many areas of basic/applied radiobiological physics and chemistry, medicine, and a variety of technological/industrial applications, including the nuclear industry. Despite decades of efforts to better understand the basic phenomena underlying the radiation chemistry of water, certain quantitative aspects of this radiolysis remain unresolved. This is especially true for ultrafast processes that link chemistry and physics following the initial energy deposition. Since water is by far the most abundant component of biological cells, understanding the interface between radiation physics and radiation chemistry of water is of obvious relevance to fundamental radiobiology. In fact, a detailed knowledge of the early physical and chemical stages of radiation action (e.g., "breaking the picosecond barrier") is of utmost importance for a reliable description of the chemical nature and the highly nonhomogeneous spatial distribution of all reactive species that are created on the (sub-) picosecond timescale and are involved as precursors to radiobiological damage     Theoretical in nature, this project, therefore, focuses primarily on the characterization of the "physicochemical stage" of radiation action. There are, in particular, three open questions that we wish to investigate over the next five years under an NSERC Discovery Grant: (i) the physical behavior of the numerous low-energy (<30 eV) electrons, generated as the radiation passes through, and their pivotal role as precursors of hydrated electrons on the transient subsequent chemistry in the radiation track development; (ii) high-dose-rate effects in the face of the considerable challenges in finding the mechanisms of the "FLASH effect", a new revolutionary modality in radiotherapy; and (iii) the fact that the aqueous medium itself is not continuous at the molecular level (all track physics programs have so far viewed water as a continuum). For this, we will attempt to generate a track in a way that recognizes the molecular nature of the target medium.     Taken together, the proposed research program will use state-of-the-art Monte Carlo methods and molecular dynamics calculations in combination with the findings from current experimental efforts to design experiment-and-theory based models to advance our knowledge of the radiolysis of (dilute and concentrated) aqueous systems. We strongly believe that early-time characterization of the underlying chemistry at the molecular level is crucial to get a complete and accurate picture of this radiolysis. It is, without a doubt, part of a major challenge in fundamental radiobiology with the long-term goal of gaining a global understanding of the effects of radiation in biological systems and using this knowledge to increase the therapeutic and diagnostic efficiency of radiation.

了解水中辐射诱导的过程对于基础/应用放射生物学物理和化学、医学以及包括核工业在内的各种技术/工业应用的许多领域都至关重要。尽管几十年来一直在努力更好地了解水的辐射化学的基本现象，但这种辐射分解的某些定量方面仍然没有得到解决。在初始能量沉积之后，将化学和物理联系起来的超快过程尤其如此。由于水是生物细胞中最丰富的成分，了解水的辐射物理和辐射化学之间的界面对基础放射生物学具有明显的相关性。事实上，详细了解辐射作用的早期物理和化学阶段(例如，“突破皮秒屏障”)对于可靠地描述在(亚)皮秒时间尺度上产生的、作为辐射生物损害前兆的所有活性物质的化学性质和高度不均匀的空间分布是极其重要的。尤其是，我们希望在未来五年内根据NSERC发现补助金研究三个悬而未决的问题：(I)在辐射通过时产生的大量低能(30 EV)电子的物理行为，以及它们作为水合电子的前体在辐射径迹发展中的瞬时后续化学中的关键作用；(Ii)面对在寻找“闪光效应”的机制方面的相当大的挑战，高剂量率效应，这是放射治疗中的一种新的革命性方式；以及(Iii)水介质本身在分子水平上不连续的事实(到目前为止，所有径迹物理项目都将水视为一个连续体)。为此，我们将尝试以一种识别目标介质的分子性质的方式生成轨迹。综上所述，拟议的研究计划将使用最先进的蒙特卡罗方法和分子动力学计算，结合当前实验工作的结果来设计基于实验和理论的模型，以提高我们对(稀释和浓缩)水体系辐射分解的了解。我们坚信，在分子水平上对潜在化学的早期表征对于获得这种辐射分解的完整和准确的图像是至关重要的。毫无疑问，这是基础放射生物学面临的重大挑战的一部分，其长期目标是全面了解辐射对生物系统的影响，并利用这一知识提高辐射的治疗和诊断效率。