硬X射线纯相位衬度图像的实验获取(英文)

Hard X-ray pure phase-contrast image obtained directly by experiment

基于自由空间传播的硬X射线相位衬度成像在生物学、医学诊断和材料科学等领域具有重要的应用.该演示实验证明,硬X射线的纯相位图像可以直接利用微焦斑X射线源获得.实验选择聚乙烯材料样品作为测试物体,样品表面划有刻痕,使用4 mm的铝片对X射线进行硬化处理,工作电压选择60 kVp.结果表明,随着放大倍数的增加,刻痕的纯相位图像越来越尖锐,而在同样条件下传统方法采集的吸收图像中,观察不到刻痕.该实验有助于理解基于传播的X射线相位衬度成像的物理机制,且验证了从双衬度图像中恢复纯相位图像方法的有效性.

Phase contrast imaging of hard X-rays based on the principle of phase propagation in free space has shown its potential prospects in the fields such as biology, medical and material science, etc. In this paper, we demonstrate that pure phase contrast image of hard X-rays can be obtained directly with a microfocus X-ray tube. A polyethylene sample is chosen as a test object and the X-rays are hardened by a 4 mm aluminum filter. The X-ray tube is operated at 60 kVp. The experimental findings are that the edge visibility of the pure phase image increases in sharpness with the increase of magnification from 2. These results not only help to comprehensively understand the X-ray phase propagation imaging but also validate the phase retrieval approaches from dual-contrast images.