Koehler Thomas, Daerr Heiner, Martens Gerhard, Kuhn Norbert, Löscher Stefan, van Stevendaal Udo, Roessl Ewald
Philips Research Laboratories, Roentgenstrasse 24-26, Hamburg D-22335, Germany.
Med Phys. 2015 Apr;42(4):1959-65. doi: 10.1118/1.4914420.
The purpose of this work is to investigate the feasibility of grating-based, differential phase-contrast, full-field digital mammography (FFDM) in terms of the requirements for field-of-view (FOV), mechanical stability, and scan time.
A rigid, actuator-free Talbot interferometric unit was designed and integrated into a state-of-the-art x-ray slit-scanning mammography system, namely, the Philips MicroDose L30 FFDM system. A dedicated phase-acquisition and phase retrieval method was developed and implemented that exploits the redundancy of the data acquisition inherent to the slit-scanning approach to image generation of the system. No modifications to the scan arm motion control were implemented.
The authors achieve a FOV of 160 × 196 mm consisting of two disjoint areas measuring 77 × 196 mm with a gap of 6 mm between them. Typical scanning times vary between 10 and 15 s and dose levels are lower than typical FFDM doses for conventional scans with identical acquisition parameters due to the presence of the source-grating G0. Only minor to moderate artifacts are observed in the three reconstructed images, indicating that mechanical vibrations induced by other system components do not prevent the use of the platform for phase contrast imaging.
To the best of our knowledge, this is the first attempt to integrate x-ray gratings hardware into a clinical mammography unit. The results demonstrate that a scanning differential phase contrast FFDM system that meets the requirements of FOV, stability, scan time, and dose can be build.
本研究旨在根据视野（FOV）、机械稳定性和扫描时间等要求，探讨基于光栅的差分相衬全场数字化乳腺摄影（FFDM）的可行性。
设计了一种无致动器的刚性塔尔博特干涉仪单元，并将其集成到最先进的X射线狭缝扫描乳腺摄影系统，即飞利浦MicroDose L30 FFDM系统中。开发并实施了一种专用的相位采集和相位恢复方法，该方法利用了狭缝扫描方法在系统图像生成中固有的数据采集冗余性。未对扫描臂运动控制进行修改。
作者获得了一个160×196mm的视野，由两个不相交的区域组成，每个区域尺寸为77×196mm，两者之间有6mm的间隙。典型扫描时间在10到15秒之间，由于源光栅G0的存在，与具有相同采集参数的传统扫描相比，剂量水平低于典型的FFDM剂量。在三张重建图像中仅观察到轻微至中度的伪影，这表明其他系统组件引起的机械振动并不妨碍该平台用于相衬成像。
据我们所知，这是首次尝试将X射线光栅硬件集成到临床乳腺摄影设备中。结果表明，可以构建一个满足视野、稳定性、扫描时间和剂量要求的扫描差分相衬FFDM系统。
