铋光栅X射线相衬成像条纹对比度的定量计算

发布时间：2019-05-17 06:02

【摘要】：吸收光栅是X射线相衬成像系统的关键器件,铋吸收光栅由于其制作成本低廉且适于在普通实验室开展制作而受到青睐。提出了一种针对铋光栅X射线相衬成像条纹对比度的定量计算方法,通过建立模型,数值计算了不同铋层厚度的吸收光栅所对应的叠栅条纹对比度,并比较了π和π/2相位光栅两种情形下的结果。结果显示,随着吸收光栅铋层厚度的增加,条纹对比度逐渐增加,当源光栅和分析光栅的铋层厚度分别达到150μm和110μm时,利用π相位光栅在40kV管电压下其条纹对比度可达48%,60kV管电压下其条纹对比度只能达到22%。而在两个吸收光栅铋层厚度相同的情况下,采用π/2相位光栅所得条纹对比度略优于π相位光栅的结果。对铋光栅X射线相衬成像条纹对比度的计算分析,可作为X射线相衬成像系统设计的参考依据,推动该成像技术走向实用化。
[Abstract]:Absorption grating is the key device of X-ray phase contrast imaging system. Bismuth absorption grating is favored because of its low cost and suitable for fabrication in ordinary laboratory. A quantitative method for calculating the contrast of X-ray phase contrast imaging stripes of bismuth gratings is presented. by establishing a model, the contrast of stacked fringes corresponding to absorption gratings with different bismuth layer thickness is calculated. The results of 蟺 and 蟺 / 2 phase gratings are compared. The results show that with the increase of bismuth layer thickness of absorption grating, the stripe contrast increases gradually. When the bismuth layer thickness of source grating and analytical grating reaches 150 渭 m and 110 渭 m, respectively, the stripe contrast of 蟺 phase grating can reach 48% at 40kV tube voltage. Under the voltage of 60kV tube, the contrast of stripes can only reach 22%. When the thickness of bismuth layer of two absorption gratings is the same, the contrast of stripes obtained by 蟺 / 2 phase gratings is slightly better than that of 蟺 phase gratings. The calculation and analysis of the contrast of X-ray phase contrast imaging stripes of bismuth gratings can be used as a reference for the design of X-ray phase contrast imaging system and promote the practical application of this imaging technology.
【作者单位】：深圳大学光电工程学院广东省/教育部光电子器件与系统重点实验室;深圳大学信息工程学院;
【基金】：国家重大科研仪器设备研制专项(61227802) 国家自然科学基金青年基金(61605119,61405120,11404221) 中国博士后科学基金面上项目(2016M592529)
【分类号】：O434.19

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