Single-Exposure, Single-Mask, Edge-Illumination X-ray Phase-Contrast Imaging Using a 7.8-µm Pixel Pitch Direct Conversion X-ray Detector

Abstract

Double-mask edge-illumination is a well-reported technique for phase-contrast x-ray imaging. Although phase retrieval using this technique is comparably easier than propagation-based phase-contrast x-ray imaging, edge-illumination can be inefficient in terms of dose efficiency and imaging time when it comes to computed tomography scanning. The illumination curve, which describes the beamlets’ intensity profile impinging upon the detector, is a key parameter that contributes to retrieving phase and absorption information. To obtain the illumination curve, multiple exposures are typically required which decreases x-ray dose efficiency and, more importantly, increases imaging time. Moreover, sample motion can negatively impact the image and information retrieval process. In this research, we employ a single mask in conjunction with a 7.8-µm pixel pitch amorphous selenium-CMOS hybrid direct conversion x-ray detector to obtain the beamlets’ intensity profile with only a single exposure. We demonstrate how using an ultra-high spatial resolution x-ray detector with a single-mask edge-illumination technique can potentially increase both dose efficiency and imaging time by at least a factor of 1.5X. Moreover, the resulting system using our approach is more compact with a source-to-detector distance of less than 30 cm. Single-exposure imaging can also help mitigate the impact of motion artifacts in the final image.