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

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.

Figure 1

(a) Schematic diagram of the EI table-top setup (not to scale). (b) Example of illumination curve measured experimentally in our laboratory setup and normalized to 1.

Figure 2

Reconstructed axial slices of the plastic phantom obtained (a) with the conventional EI retrieval algorithm and (b) with the single-image-retrieval algorithm. The objects inside the phantom are (1) a hollow plastic cylinder, (2) a plastic rod, (3) a second, smaller hollow plastic cylinder, (4) rolled plastic paraffin film, and (5) chalk inside a plastic container.

Figure 3

Ground beetle: (a) axial slice reconstructed using the single-image method and (b) a vertical section through the volume. Rat heart: (c) axial slice reconstructed using the single-image method, (d) a vertical section through the volume, (e) corresponding preliminary result obtained using the single-photon-counting Pixirad detector.