作为 X 射线相衬成像的方法之一,衍射增强成像方法由于能获得较高的信噪比及分辨率而引起了人们的研究兴趣。北京同步辐射装置(BSRF)形貌学实验站也开展了该方法的探索研究。此前的衍射增强成像方法中,当白光 X 射线光束横截面尺寸为 20...作为 X 射线相衬成像的方法之一,衍射增强成像方法由于能获得较高的信噪比及分辨率而引起了人们的研究兴趣。北京同步辐射装置(BSRF)形貌学实验站也开展了该方法的探索研究。此前的衍射增强成像方法中,当白光 X 射线光束横截面尺寸为 20 mm×10 mm 时,经过双晶单色器后最大只能获得横截面尺寸为20 mm×4 mm 的均匀单色 X 射线,从而造成成像区域减小。在对通常衍射增强成像光路排列分析的基础上,提出了一种新的光学排列几何并进行了衍射增强实验。应用新光学排列几何首次获得了与入射白光 X 射线尺寸相当的、大的成像光斑均匀区域,因而新光学排列几何更适合于大尺寸样品的研究工作。同时,该光学排列几何成像分辨率可以达到微米量级并且更方便于实验操作。展开更多
Two algorithms for the phase retrieval of hard X-ray in-line phase contrast imaging are presented. One is referred to as Iterative Angular Spectrum Algorithm (IASA) and the other is a hybrid algorithm that combines IA...Two algorithms for the phase retrieval of hard X-ray in-line phase contrast imaging are presented. One is referred to as Iterative Angular Spectrum Algorithm (IASA) and the other is a hybrid algorithm that combines IASA with TIE (transport of intensity equation). The calculations of the algorithms are based on free space propagation of the angular spectrum. The new approaches are demonstrated with numerical simulations. Comparisons with other phase retrieval algorithms are also performed. It is shown that the phase retrieval method combining the IASA and TIE is a promising technique for the application of hard X-ray phase contrast imaging.展开更多
Imaging blood vessels is of importance for determining the vascular distribution of organs and tumors.Phase-contrast X-ray imaging can reveal the vessels in much more detail than conventional X-ray absorption method.V...Imaging blood vessels is of importance for determining the vascular distribution of organs and tumors.Phase-contrast X-ray imaging can reveal the vessels in much more detail than conventional X-ray absorption method.Visualizing murine liver microvasculature ex vivo with phase-contrast X-ray imaging was performed at Shanghai Synchrotron Radiation Facility.Barium sulfate and physiological saline were used as contrast agents for the blood vessels.Blood vessels of <Φ20μm could be detected by replacing resident blood with physiological saline or barium sulfate.An entire branch of the portal vein (from the main axial portal vein to the ninth generation of branching) could be captured in a single phase-contrast image.It is demonstrated that selective angiography based on phase contrast X-ray imaging,with a physiological material of low Z elements (such as saline) being the contrast agent,is a viable imaging strategy.Further efforts will be focused on using the technique to image tumor angiogenesis.展开更多
文摘作为 X 射线相衬成像的方法之一,衍射增强成像方法由于能获得较高的信噪比及分辨率而引起了人们的研究兴趣。北京同步辐射装置(BSRF)形貌学实验站也开展了该方法的探索研究。此前的衍射增强成像方法中,当白光 X 射线光束横截面尺寸为 20 mm×10 mm 时,经过双晶单色器后最大只能获得横截面尺寸为20 mm×4 mm 的均匀单色 X 射线,从而造成成像区域减小。在对通常衍射增强成像光路排列分析的基础上,提出了一种新的光学排列几何并进行了衍射增强实验。应用新光学排列几何首次获得了与入射白光 X 射线尺寸相当的、大的成像光斑均匀区域,因而新光学排列几何更适合于大尺寸样品的研究工作。同时,该光学排列几何成像分辨率可以达到微米量级并且更方便于实验操作。
基金supported by the National Natural Science Foundation of China(Grant No.60472107)the Natural Science Foundation of Guangdong Province(Grant Nos.04300862 and 04300864)Shenzhen Bureau of Science,Technology&Information(Grant No.200426).
文摘Two algorithms for the phase retrieval of hard X-ray in-line phase contrast imaging are presented. One is referred to as Iterative Angular Spectrum Algorithm (IASA) and the other is a hybrid algorithm that combines IASA with TIE (transport of intensity equation). The calculations of the algorithms are based on free space propagation of the angular spectrum. The new approaches are demonstrated with numerical simulations. Comparisons with other phase retrieval algorithms are also performed. It is shown that the phase retrieval method combining the IASA and TIE is a promising technique for the application of hard X-ray phase contrast imaging.
基金Supported by National Basic Research Program of China (973 Program Grant No.2010CB834305)
文摘Imaging blood vessels is of importance for determining the vascular distribution of organs and tumors.Phase-contrast X-ray imaging can reveal the vessels in much more detail than conventional X-ray absorption method.Visualizing murine liver microvasculature ex vivo with phase-contrast X-ray imaging was performed at Shanghai Synchrotron Radiation Facility.Barium sulfate and physiological saline were used as contrast agents for the blood vessels.Blood vessels of <Φ20μm could be detected by replacing resident blood with physiological saline or barium sulfate.An entire branch of the portal vein (from the main axial portal vein to the ninth generation of branching) could be captured in a single phase-contrast image.It is demonstrated that selective angiography based on phase contrast X-ray imaging,with a physiological material of low Z elements (such as saline) being the contrast agent,is a viable imaging strategy.Further efforts will be focused on using the technique to image tumor angiogenesis.
