辐射生物效应中微剂量学细胞模型初步研究

发布时间：2018-10-26 10:36

【摘要】：人体辐射健康危害取决于辐射能量在人体的沉积分布及后续复杂的生物学过程。依据辐射损伤机制经典学说--靶学说，DNA分子是辐射损伤最重要的靶，辐射能量在其内的沉积特点对辐射生物效应的解释具有重要意义。考虑到细胞是人体的基本功能单元且DNA分子受损后的各种生物学响应均与细胞环境有关，因此，在细胞水平开展辐射剂量学研究对辐射损伤机制的深入了解及其在辐射防护和放射治疗等方面的实用化具有重要意义。目的：单细胞模型是辐射能量在细胞水平上沉积特点和规律获取的重要平台。本文旨在得到合理可行的单细胞模型建立方法，并据此建立更加接近真实细胞的Monte Carlo计算模型。材料与方法：采用具有肿瘤细胞代表性的人口腔上皮癌细胞作为研究对象，基于生物学手段和计算机图形技术摸索模型的建立方法，并结合GEANT4蒙特卡罗模拟软件进行辐射照射下细胞内能量沉积规律的获取。结果：成功建立了单细胞模型，并针对该模型进行了适用性和实用性的测试。在此基础上进行了剂量学计算，结果表明，在综合考虑计算时间和计算精度的情况下对7组数据进行分析，最终将图像分辨率设为0.3-0.4μm范围内，用200个3MeV的α粒子对单细胞模型进行照射，，得到细胞核内单个粒子击中细胞的平均比能均值为0.209Gy；细胞质内单个粒子击中细胞的平均比能均值为0.044Gy。本文得到的计算结果与已公布数据吻合，建立单细胞体素模型的方法切实可行且通用性强；细胞核的密度与细胞形态对模型计算结果有重要影响，建立不同细胞系的细胞库是对于放射生物学的研究非常有必要的。
[Abstract]:Radiation health hazard depends on the deposition and distribution of radiation energy in human body and subsequent complex biological processes. According to the classical theory of radiation damage mechanism, target theory, DNA molecule is the most important target of radiation damage. Considering that cells are the basic functional units of the human body and that the various biological responses of damaged DNA molecules are related to the cellular environment, Radiation dosimetry at the cellular level is of great significance in understanding the mechanism of radiation damage and in radiation protection and radiation therapy. Objective: single cell model is an important platform for obtaining the characteristics and regularity of radiation energy deposition at cell level. The purpose of this paper is to obtain a reasonable and feasible method for establishing a single cell model, and then to establish a Monte Carlo calculation model which is closer to the real cell. Materials and methods: human oral epithelial cancer cells, which are representative of tumor cells, were used as research objects. GEANT4 Monte Carlo simulation software was used to obtain the intracellular energy deposition under radiation irradiation. Results: a single cell model was successfully established, and the applicability and practicability of the model were tested. On this basis, dosimetric calculations are carried out. The results show that seven groups of data are analyzed under the consideration of calculation time and accuracy, and the image resolution is set to 0.3-0.4 渭 m. The single cell model was irradiated with 200 伪 particles of 3MeV, and the average specific energy of a single particle in the nucleus was 0.209 Gy. The average specific energy of a single particle in the cytoplasm was 0.044 GY. The results obtained in this paper are in agreement with the published data. The method of establishing a single cell voxel model is feasible and universal. Nuclear density and cell morphology have important influence on the results of the model. It is necessary to establish cell banks of different cell lines for the study of radiobiology.
【学位授予单位】：苏州大学
【学位级别】：硕士
【学位授予年份】：2013
【分类号】：R144.1

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