基于X射线光栅相位衬度的小动物无损成像研究

发布时间：2018-11-11 11:01

【摘要】：近年来,X射线光栅相位衬度成像成为当前X射线成像学界的研究热点,因其与传统X光源的高度兼容性而被认为是未来临床医学无损诊断的关键技术。与现有的X射线吸收衬度成像技术相比,相位衬度成像技术在对软组织等轻元素样品成像时具有不可替代的分辨能力,能够同时获得动物和人体的骨骼、器官等硬组织和软组织的高衬度、大视场、免造影的三维结构成像。该技术在一次成像过程中,可以通过信息分离算法获得吸收衬度图像、相位衬度图像和散射衬度图像,三者各有特色,又相互补充,获取的信息量远超过传统医用X射线CT装置,因此在癌症早期防治、免造影诊断、动物无损研究等方面具有重要的科研价值和潜在的应用前景。本论文利用中国科学技术大学国家同步辐射实验室的一个基于几何投影的X射线光栅相位衬度成像实验平台,开展小动物的无损成像研究。基于该平台,本论文主要开展了以下两方面的工作:1.基于X射线光栅相位衬度的小鼠肺部无损成像研究肺癌是临床死亡率最高的恶性肿瘤之一,寻找更为有效的早期诊断手段成为治疗肺癌等恶性肿瘤的迫切要求。我们利用基于几何投影的X射线相位衬度成像技术,对植有黑色素瘤的小鼠肺部进行无损成像研究,在X射线相位衬度成像应用于肺癌早期诊断方面进行了有益的尝试。实验结果显示:在植有黑色素瘤癌变的小鼠肺部样品的相位衬度图像中,不但观察到了表面凸起的黑色素瘤,而且还展示了其内部癌变组织的丰富细节,并且其衬噪比高于正常肺部。上述研究证明了利用光栅相位衬度成像实现肺癌早期检测的可能性,在肺癌早期诊断方面具有成像快、清晰等独特优势。2.基于X射线光栅相位衬度的鲫鱼无损成像研究探究常用鱼类的结构对于确保食品安全和人体健康具有非常重要的意义。我们基于几何投影的X射线光栅相位衬度成像技术,无损研究活体鲫鱼的鱼体结构,利用福尔马林溶液处理样品,发现成像结果清楚地显示出鱼肠软组织的结构。这是第一次利用常规X射线光源的光栅相位衬度成像技术观察到鱼肠软组织。我们还发现,经福尔马林溶液处理鲫鱼样品的吸收衬度图像、相位衬度图像和散射衬度图像的衬噪比均优于新鲜鲫鱼样品,表明这种样品处理方法可以作为X射线光栅相位衬度成像无损检测实验样品处理方法的重要参考。
[Abstract]:In recent years, X-ray grating phase contrast imaging has become a hot spot in the field of X-ray imaging. Because of its high compatibility with the traditional X-ray light source, it is considered to be the key technology of nondestructive diagnosis in clinical medicine in the future. Compared with the existing X-ray absorption-contrast imaging technology, the phase contrast imaging technique has irreplaceable resolution in imaging light element samples, such as soft tissue, and can obtain both animal and human bones. High contrast, large field of view, and non-contrast three-dimensional structure imaging of hard tissue and soft tissue such as organs. In the first imaging process, the absorption contrast image, the phase contrast image and the scattering contrast image can be obtained by the information separation algorithm. The three images have their own characteristics and complement each other. The amount of information obtained is much higher than that of the traditional medical X-ray CT device, so it has important scientific research value and potential application prospect in early cancer prevention and treatment, non-angiographic diagnosis, animal nondestructive research and so on. In this paper, the experimental platform of X-ray grating phase contrast imaging based on geometric projection is used in the National Synchrotron radiation Laboratory of the University of Science and Technology of China to study the nondestructive imaging of small animals. Based on the platform, this paper mainly carried out the following two aspects of work: 1. Non-destructive imaging of lung in mice based on phase contrast X-ray grating is one of the most fatal malignant tumors in clinic. It is an urgent requirement to find more effective early diagnostic methods for lung cancer and other malignant tumors. We have studied the nondestructive imaging of the lungs of mice implanted with melanoma by using the technique of phase contrast X-ray imaging based on geometric projection. We have made a useful attempt in the application of phase contrast imaging in the early diagnosis of lung cancer. The results showed that in the phase contrast images of lung samples of mice with melanoma carcinogenesis, not only the protruding melanoma on the surface was observed, but also the rich details of the cancerous tissue inside the tumor were shown. The ratio of contrast to noise is higher than that of normal lung. These studies prove the possibility of using grating phase contrast imaging to realize early detection of lung cancer, which has the unique advantages of fast imaging and clarity in early diagnosis of lung cancer. 2. Non-destructive Imaging of Carassius auratus based on X-ray grating Phase contrast it is very important to explore the structure of common fish for ensuring food safety and human health. Based on the geometric projection of X-ray grating phase contrast imaging technique, we studied the fish structure of live crucian carp without damage. The samples were treated with formalin solution, and the structure of the soft tissue of fish intestines was clearly shown by the imaging results. This is the first time to observe the soft tissue of fish intestines using raster phase contrast imaging with conventional X-ray sources. We also find that the contrast ratio of the phase contrast image and the scattering contrast image is better than that of the fresh crucian carp sample treated with formalin solution. It is shown that this method can be used as an important reference for the experimental sample processing of X-ray grating phase contrast imaging nondestructive testing.
【学位授予单位】：中国科学技术大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：R814;O434.19

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