使用辐射自显影胶片对重离子治癌的剂量学验证研究

发布时间：2018-07-08 08:55

本文选题：重离子治癌 + 辐射自显影胶片　；参考：《清华大学》2013年硕士论文

【摘要】：本课题的主要目的是寻找一个重离子束治癌时剂量的验证方法。经过前期的考察，选择使用EBT2胶片，可能会使验证程序更为简便、结果更为准确。经过分析EBT2胶片的一系列特性，从而确定其用于剂量验证的可行性。课题首先研究了EBT2胶片的一些特性，这些特性包括感光特性、扫描特性等。基于这些特性，建立了由EBT2胶片和EPSON10000XL平板扫描仪组成的一套剂量验证系统，并对该系统的使用方法做了更详细的研究。分别研究了该系统的组成、校准、扫描胶片的操作方法、以及扫描后图像的存储、图像的分析，，像素值的提取、转换为绝对剂量等。通过以上研究我们明确了该系统的使用方法及流程，得到了操作规范，为之后的研究奠定了基础。其次利用上述系统对EBT2胶片对重离子束的响应特性做了深入的研究，主要研究EBT2胶片的能量响应特性和剂量响应特性。选取3种不同能量的重离子束照射EBT2胶片后发现，响应曲线大约成指数关系，用一个经验公式的最小二乘法拟合曲线，得到曲线特性参数，结果发现EBT2胶片对重离子束的能量响应没有差异。通过严格的标定胶片的净光密度值和绝对剂量，得到EBT2胶片对重离子束的剂量响应特性，发现净光密度与绝对剂量不是成线性关系，用一个3次多项式即可很好地拟合这个曲线。由拟合曲线即可很方便的将拍摄到的胶片的光密度值转换为绝对剂量。通过研究我们发现，使用EBT2胶片配合EPSON10000XL平板扫描仪组成的剂量验证系统，来对重离子治癌的剂量验证是可行的，并且操作便捷、结果精确。
[Abstract]:The main purpose of this project is to find a method to verify the dose of a heavy ion beam for cancer treatment. After a preliminary investigation, the selection of EBT2 film may make the verification program more convenient and more accurate. After analyzing a series of characteristics of EBT2 film, the feasibility of its dose verification is determined.
Firstly, some characteristics of EBT2 film are studied. These characteristics include photosensitive and scanning characteristics. Based on these characteristics, a set of dose verification system composed of EBT2 film and EPSON10000XL plate scanner is established, and the use method of the system is studied in more detail. The composition, calibration and scanning of the system are studied respectively. The operation method of the film, the storage of the image after scanning, the analysis of the image, the extraction of the pixel value, and the conversion to the absolute dose. Through the above study, we have made clear the method and process of the system, and got the operation specification, which laid the foundation for the later research.
Secondly, the response characteristics of the heavy ion beam on EBT2 film are deeply studied by using the above system. The energy response characteristics and the dose response characteristics of the EBT2 film are mainly studied. The response curves of 3 kinds of heavy ion beams with different energy are selected and the response curve is about exponential relation, and the least square method of an empirical formula is used to fit the curve. It is found that the energy response of the EBT2 film has no difference to the heavy ion beam. By strictly calibrating the net light density and absolute dose of the film, the dose response characteristic of the EBT2 film to the heavy ion beam is obtained. It is found that the net light density is not linear with the absolute dose, and the 3 polynomial can be good. Fitting the curve, it is easy to convert the optical density of photographic film to absolute dose by fitting curve.
Through the study, we found that the dose verification system composed of EBT2 film and EPSON10000XL plate scanner is feasible for the dose verification of heavy ion cancer treatment, and the operation is convenient and the result is accurate.
【学位授予单位】：清华大学
【学位级别】：硕士
【学位授予年份】：2013
【分类号】：R730.55

【参考文献】