Department of Medical Physics, University of Wisconsin-Madison, Madison, Wisconsin 53705, USA.
Med Phys. 2011 Feb;38(2):584-8. doi: 10.1118/1.3533718.
The noise variance versus spatial resolution relationship in differential phase contrast (DPC) projection imaging and computed tomography (CT) are derived and compared to conventional absorption-based x-ray projection imaging and CT.
The scaling law for DPC-CT is theoretically derived and subsequently validated with phantom results from an experimental Talbot-Lau interferometer system.
For the DPC imaging method, the noise variance in the differential projection images follows the same inverse-square law with spatial resolution as in conventional absorption-based x-ray imaging projections. However, both in theory and experimental results, in DPC-CT the noise variance scales with spatial resolution following an inverse linear relationship with fixed slice thickness.
The scaling law in DPC-CT implies a lesser noise, and therefore dose, penalty for moving to higher spatial resolutions when compared to conventional absorption-based CT in order to maintain the same contrast-to-noise ratio.
推导并比较了差分相衬（DPC）投影成像和计算机断层扫描（CT）中的噪声方差与空间分辨率之间的关系，与传统的基于吸收的 X 射线投影成像和 CT 进行了比较。
从理论上推导出 DPC-CT 的标度定律，并随后通过实验 Talbot-Lau 干涉仪系统的体模结果进行验证。
对于 DPC 成像方法，差分投影图像中的噪声方差随空间分辨率的变化遵循与传统基于吸收的 X 射线成像投影相同的平方反比定律。然而，无论是在理论上还是实验结果中，在 DPC-CT 中，噪声方差随空间分辨率的变化遵循与固定切片厚度的线性反比关系。
与传统的基于吸收的 CT 相比，DPC-CT 的标度定律意味着在为了保持相同的对比噪声比而移动到更高的空间分辨率时，噪声（因此剂量）的惩罚较小。
