节点文献
同步辐射X射线肿瘤新生血管成像及相衬成像理论研究
【作者】 刘晓霞；
【作者基本信息】 上海交通大学 ， 生物医学工程， 2010， 硕士
【摘要】 肿瘤新生血管对于肿瘤的生长、转移具有重要作用,其直径约为几十微米甚至更小。但目前传统影像技术只能分辨直径大于200微米的血管。同步辐射相衬成像技术对生物软组织如血管、肿瘤等的成像具有巨大的优势,空间分辨率可达1微米。本研究初步尝试了利用上海同步辐射光源观察正常小鼠和Lewis肺癌鼠的胸部结构和血管。利用同步辐射类同轴相衬成像技术,可以很好的区分Lewis肺癌鼠肺部的正常区域和肿瘤区域;同时,在使用硫酸钡造影剂的情况下,观察到了沿肿瘤边缘区域的肿瘤新生血管。此外,建立了小鼠4T1乳腺癌脊皮视窗模型,探索了在不使用造影剂的情况下对小鼠乳腺癌肿瘤新生血管的形态与结构进行观察。结果表明,利用同步辐射相衬成像能够在不使用造影剂的情况下观察到直径小于30微米的肿瘤新生血管。此外,根据同步辐射类同轴相衬成像原理,利用计算机模拟研究能量,成像距离和样品厚度对成像质量的影响。结果表明,在医学影像成像的能量范围内,能量增高,会降低图像衬度;样品厚度对图像衬度的影响不明显;图像衬度随着成像距离的增加刚开始增强,距离进一步拉大,图像反而变模糊。模拟计算结果与实际实验结果能够较好的吻合,对下一步的实验具有一定的指导意义。研究结果表明利用同步辐射光源观察肿瘤微血管的实验方法具有可行性。在今后的研究中,我们将通过建立肿瘤模型进一步研究它们的发病机理以及诊断治疗的方法。
【Abstract】 Angiogenesis plays an important role in tumor growth and metastasis. However, only vessels lager than 200μm in diameter can be observed using conventional medical imaging system. Synchrotron radiation (SR) phase contrast imaging, whose spatial resolution can reach 1μm, as the highest, has great advantages in imaging soft tissue structure, such as blood vessels and tumors.In this study, BALB/c nude mouse with Lewis lung cancer implanted was studied using Shanghai Synchrotron Radiation Facility. The images clearly showed the differences between the tumor tissue and the normal lung tissue. The effect of the object-detector distance and energy level on the phase contrast difference was investigated, in good agreement with the theory of in-line phase contrast imaging. Moreover, 3D tumor angiogenesis of lung cancer was obtained for the first time through reconstruction and using contrast agent, demonstrating the feasibility of micro-angiography with synchrotron radiation for imaging tumor angiogenesis deep inside the body. Meanwhile, angiogenesis in tumor chamber was imaged using SR in-line phase contrast imaging without contrast agent, showing that vessels less than 30μm in diameter can be observed.On the other hand, computer simulation of in line phase contrast imaging was adopted to study the influences of energy level, imaging distance and thickness of sample on the image quality. The simulation results, in good accordance with the experiment results, showed that image contrast decreased when energy increased and the thickness of sample did not obviously affect the image quality and the image contrast first increased along with the distance then decreased in a longer distance.The above results showed the feasibility of observation of micro-vessels in tumor using synchrotron radiation in line phase contrast imaging. Further study on the pathogenesis, diagnosis and treatment of tumor by establishing animal models will be investigated.
【Key words】 synchrotron radiation； phase contrast imaging； lung cancer； angiogenesis；