Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201204, China.
Opt Lett. 2011 May 1;36(9):1719-21. doi: 10.1364/OL.36.001719.
Phase retrieval extracts quantitative phase information from x-ray propagation-based phase-contrast images. Notwithstanding inherent approximations, phase retrieval using a single sample-to-detector distance (SDD) is very attractive, because it imposes no setup complications or additional radiation dose compared to absorption-based imaging. Considering the phase-attenuation duality (ε=δ/β, where ε is constant), a simple absorption correction factor is proposed for the modified Bronnikov algorithm in x-ray propagation-based phase-contrast computed tomography (PPCT). Moreover, a practical method for calculating the optimal ε value is proposed, which requires no prior knowledge of the sample. Tests performed on simulation and experimental data successfully distinguished different materials in a quasihomogeneous and weakly absorbing sample from a single SDD-PPCT data point.
相衬恢复从基于 X 射线传播的相衬图像中提取定量相位信息。尽管存在固有近似，但是使用单个样品到探测器距离（SDD）的相衬恢复非常有吸引力，因为与基于吸收的成像相比，它不会增加设置复杂性或额外的辐射剂量。考虑到相位衰减对偶性（ε=δ/β，其中ε是常数），针对基于 X 射线传播的相衬计算机断层扫描（PPCT）中的修改后的 Bronnikov 算法，提出了一个简单的吸收校正因子。此外，还提出了一种计算最佳ε值的实用方法，该方法不需要样品的先验知识。在模拟和实验数据上的测试成功地从单个 SDD-PPCT 数据点区分了具有相同准均匀和弱吸收的不同材料。
