Single-Shot X-Ray Phase-Contrast Computed Tomography with Nonmicrofocal Laboratory Sources

Abstract

We present a method that enables performing x-ray phase-contrast imaging (XPCI) computed tomography with a laboratory setup using a single image per projection angle, eliminating the need to move optical elements during acquisition. Theoretical derivation of the method is presented, and its validity conditions are provided. The object is assumed to be quasihomogeneous, i.e., to feature a ratio between the refractive index and the linear attenuation coefficient that is approximately constant across the field of view. The method is experimentally demonstrated on a plastics phantom and on biological samples using a continuous rotation acquisition scheme achieving scan times of a few minutes. Moreover, we show that such acquisition times can be further reduced with the use of a high-efficiency photon-counting detector. Thanks to its ability to substantially simplify the image-acquisition procedure and greatly reduce collection times, we believe this method represents a very important step towards the application of XPCI to real-world problems.

Laboratory-based x-ray phase contrast CT technology for clinical intra-operative specimen imaging

“…Single image phase retrieval has been used for all data resulting in CT scans. 30 Examples of the results achievable with the proposed system on breast samples are shown in Fig.6. 2D phase contrast radiography is acquired within few seconds (see Fig.6a).…”

“…To overcome this limitation, phase retrieval approaches based on the acquisition of a single image have been developed. 29,30 The acquisition of a single image allows to continuously rotate the sample, thus decreasing scanning time and making tomography compatible with the requirements of intra-operative imaging.…”

A Preliminary Investigation into the Use of Edge Illumination X-ray Phase Contrast Micro-CT for Preclinical Imaging

“…For example, separate attenuation and phase images can be retrieved, or, like in grating interferometry, a third, ultrasmall-angle scattering channel can be accessed when the method is operated in dark field mode [18]. Alternatively, the refraction-based edge signal can be converted into area signal and merged with the attenuation contrast, enabling the reconstruction of hybrid (i.e., combined phase and attenuation) images [19]. As a second flexible aspect, the spatial resolution can be adjusted via the acquisition parameters [20].…”

“…The reconstruction of hybrid images, in which attenuation and phase contrast are combined, was enabled by a singleframe phase retrieval method [19]. This requires that frames are collected at only one working point per rotation angle.…”

Implementation of a double-grating interferometer for phase-contrast computed tomography in a conventional system nanotom® m

“…13 Several research teams have built computed tomography systems working in the phasecontrast mode. [16][17][18][19] Grating interferometry is a phase-contrast imaging technique especially powerful with regard to its quantitativeness and distinctive contrast, even if polychromatic sources are used. 20 As the pixel sizes of commercially available detectors are generally too large to resolve the interference pattern directly, as required for a single-grating set-up, 21 grating interferometry is preferentially performed in two-and three-grating configurations.…”