光子学报, 2019, 48 (1): 0111003, 网络出版: 2019-01-27
基于级联光栅的X射线相衬成像实验研究
Experimental Study of X-ray Phase Contrast Imaging Based on Cascaded Grating
X射线成像 相位衬度 泰伯-劳干涉仪 逆泰伯-劳干涉仪 灵敏度 X-ray imaging Phase contrast Talbot-Lau interferometer Inverse Talbot-Lau interferometer Sensitivity
摘要
为避免小周期高宽比吸收光栅的制作, 提出了由泰伯-劳干涉仪和逆泰伯-劳干涉仪组成的级联光栅X射线相衬成像装置, 该装置利用泰伯-劳干涉仪的自成像作为逆泰伯-劳干涉仪的源.通过实验验证了该方法的有效性, 得到了成像系统的莫尔条纹和强度振荡曲线.条纹最高对比度为17.4%, 随着吸收光栅偏离零点位置, 条纹对比度逐渐降低, 但是在其位置跨越从-17 mm到12 mm的范围内, 条纹对比度仍保持在10%以上.实验讨论了样品位置对成像灵敏度的影响, 结果表明当样品位置靠近相位光栅两侧时, 其成像灵敏度最高.本文的研究可应用于生物医学成像的大视场X射线相衬成像系统的设计.
Abstract
A cascade interferometer for X-ray phase-contrast imaging composed by a Talbot-Lau interferometer and an inverse Talbot-Lau interferometer was implemented, which the self-image of Talbot-Lau interferometer being used as the source of the inverse Talbot-Lau interferometer, with the purpose to avoid the fabrication of small-period high aspect-ratio absorption gratings. Experiments validated the method,while moire fringes and intensity oscillation curves of the imaging system are obtained. The maximum visibility of the fringes was 17.4%. With the absorption grating deviating from the zero position, the visibility of the fringes decreased gradually. But it remained above 10%, when the position of the absorption grating spaned from -17 mm to 12 mm. And the angular sensitivity as a function of the sample position was discussed. Results show that the highest sensitivity is obtained, when the investigated object is close to the phase grating. This will be useful for designing an X-ray phase-contrast imaging system for applications of biomedical imaging in large field of view.
李冀, 黄建衡, 雷耀虎, 刘鑫, 赵志刚. 基于级联光栅的X射线相衬成像实验研究[J]. 光子学报, 2019, 48(1): 0111003. LI Ji, HUANG Jian-heng, LEI Yao-hu, LIU Xin, ZHAO Zhi-gang. Experimental Study of X-ray Phase Contrast Imaging Based on Cascaded Grating[J]. ACTA PHOTONICA SINICA, 2019, 48(1): 0111003.