An iterative image reconstruction algorithm combined with forward and backward diffusion filtering for in-line X-ray phase-contrast computed tomography

In-line X-ray phase-contrast computed tomography (IL-PCCT) can reveal fine inner structures for low-Z materials (e.g. biological soft tissues), and shows high potential to become clinically applicable. Typically, IL-PCCT utilizes filtered back-projection (FBP) as the standard reconstruction algorithm. However, the FBP algorithm requires a large amount of projection data, and subsequently a large radiation dose is needed to reconstruct a high-quality image, which hampers its clinical application in IL-PCCT. In this study, an iterative reconstruction algorithm for IL-PCCT was proposed by combining the simultaneous algebraic reconstruction technique (SART) with eight-neighbour forward and backward (FAB8) diffusion filtering, and the reconstruction was performed using the Shepp–Logan phantom simulation and a real synchrotron IL-PCCT experiment. The results showed that the proposed algorithm was able to produce high-quality computed tomography images from few-view projections while improving the convergence rate of the computed tomography reconstruction, indicating that the proposed algorithm is an effective method of dose reduction for IL-PCCT.

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Level-set reconstruction algorithm for ultrafast limited-angle X-ray computed tomography of two-phase flows

Philosophical Transactions of The Royal Society A Mathematical Physical and Engineering Sciences ◽

10.1098/rsta.2014.0395 ◽

2015 ◽

Vol 373 (2043) ◽

pp. 20140395 ◽

Cited By ~ 3

Author(s):

M. Bieberle ◽

U. Hampel

Keyword(s):

Computed Tomography ◽

Level Set ◽

Reconstruction Algorithm ◽

Projection Data ◽

Reconstruction Technique ◽

Two Phase Flows ◽

Two Phase ◽

X Ray ◽

X Ray Computed ◽

Limited Angle

Tomographic image reconstruction is based on recovering an object distribution from its projections, which have been acquired from all angular views around the object. If the angular range is limited to less than 180° of parallel projections, typical reconstruction artefacts arise when using standard algorithms. To compensate for this, specialized algorithms using a priori information about the object need to be applied. The application behind this work is ultrafast limited-angle X-ray computed tomography of two-phase flows. Here, only a binary distribution of the two phases needs to be reconstructed, which reduces the complexity of the inverse problem. To solve it, a new reconstruction algorithm (LSR) based on the level-set method is proposed. It includes one force function term accounting for matching the projection data and one incorporating a curvature-dependent smoothing of the phase boundary. The algorithm has been validated using simulated as well as measured projections of known structures, and its performance has been compared to the algebraic reconstruction technique and a binary derivative of it. The validation as well as the application of the level-set reconstruction on a dynamic two-phase flow demonstrated its applicability and its advantages over other reconstruction algorithms.

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A new in-line X-ray phase-contrast computed tomography reconstruction algorithm based on adaptive-weighted anisotropic TpV regularization for insufficient data

Journal of Synchrotron Radiation ◽

10.1107/s1600577519005095 ◽

2019 ◽

Vol 26 (4) ◽

pp. 1330-1342

Author(s):

Yuqing Zhao ◽

Dongjiang Ji ◽

Yingpin Chen ◽

Jianbo Jian ◽

Xinyan Zhao ◽

...

Keyword(s):

Computed Tomography ◽

Radiation Dose ◽

Phase Contrast ◽

Convex Sets ◽

Soft Tissues ◽

Reconstruction Algorithm ◽

Insufficient Data ◽

Ct Reconstruction ◽

X Ray ◽

Image Gradients

In-line X-ray phase-contrast computed tomography (IL-PCCT) is a valuable tool for revealing the internal detailed structures in weakly absorbing objects (e.g. biological soft tissues), and has a great potential to become clinically applicable. However, the long scanning time for IL-PCCT will result in a high radiation dose to biological samples, and thus impede the wider use of IL-PCCT in clinical and biomedical imaging. To alleviate this problem, a new iterative CT reconstruction algorithm is presented that aims to decrease the radiation dose by reducing the projection views, while maintaining the high quality of reconstructed images. The proposed algorithm combines the adaptive-weighted anisotropic total p-variation (AwaTpV, 0 < p < 1) regularization technique with projection onto convex sets (POCS) strategy. Noteworthy, the AwaTpV regularization term not only contains the horizontal and vertical image gradients but also adds the diagonal image gradients in order to enforce the directional continuity in the gradient domain. To evaluate the effectiveness and ability of the proposed algorithm, experiments with a numerical phantom and synchrotron IL-PCCT were performed, respectively. The results demonstrated that the proposed algorithm had the ability to significantly reduce the artefacts caused by insufficient data and effectively preserved the edge details under noise-free and noisy conditions, and thus could be used as an effective approach to decrease the radiation dose for IL-PCCT.

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Visualization Ability of Phase-Contrast Synchrotron-Based X-Ray Imaging Using an X-Ray Interferometer in Soft Tissue Tumors

Technology in Cancer Research & Treatment ◽

10.1177/15330338211010121 ◽

2021 ◽

Vol 20 ◽

pp. 153303382110101

Author(s):

Thet-Thet Lwin ◽

Akio Yoneyama ◽

Hiroko Maruyama ◽

Tohoru Takeda

Keyword(s):

Computed Tomography ◽

Soft Tissue ◽

Spatial Resolution ◽

Phase Contrast ◽

Soft Tissue Tumors ◽

X Ray ◽

3 Dimensional ◽

Computed Tomography Images ◽

X Ray Imaging ◽

X Ray Computed

Phase-contrast synchrotron-based X-ray imaging using an X-ray interferometer provides high sensitivity and high spatial resolution, and it has the ability to depict the fine morphological structures of biological soft tissues, including tumors. In this study, we quantitatively compared phase-contrast synchrotron-based X-ray computed tomography images and images of histopathological hematoxylin-eosin-stained sections of spontaneously occurring rat testicular tumors that contained different types of cells. The absolute densities measured on the phase-contrast synchrotron-based X-ray computed tomography images correlated well with the densities of the nuclear chromatin in the histological images, thereby demonstrating the ability of phase-contrast synchrotron-based X-ray imaging using an X-ray interferometer to reliably identify the characteristics of cancer cells within solid soft tissue tumors. In addition, 3-dimensional synchrotron-based phase-contrast X-ray computed tomography enables screening for different structures within tumors, such as solid, cystic, and fibrous tissues, and blood clots, from any direction and with a spatial resolution down to 26 μm. Thus, phase-contrast synchrotron-based X-ray imaging using an X-ray interferometer shows potential for being useful in preclinical cancer research by providing the ability to depict the characteristics of tumor cells and by offering 3-dimensional information capabilities.

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Visualization of microvasculature and thrombi by X-ray phase-contrast computed tomography in hepatocellular carcinoma

Journal of Synchrotron Radiation ◽

10.1107/s1600577516001016 ◽

2016 ◽

Vol 23 (2) ◽

pp. 600-605 ◽

Cited By ~ 8

Author(s):

Jianbo Jian ◽

Hao Yang ◽

Xinyan Zhao ◽

Ruijiao Xuan ◽

Yujie Zhang ◽

...

Keyword(s):

Computed Tomography ◽

Hepatocellular Carcinoma ◽

Phase Contrast ◽

Soft Tissues ◽

Three Dimensional ◽

X Ray ◽

Density Distributions ◽

Fine Structures ◽

Tumor Growth And Metastasis ◽

Micrometer Scale

Visualization of the microvascular network and thrombi in the microvasculature is a key step to evaluating the development of tumor growth and metastasis, and influences treatment selection. X-ray phase-contrast computed tomography (PCCT) is a new imaging technique that can detect minute changes of density and reveal soft tissues discrimination at micrometer-scale resolution. In this study, six human resected hepatocellular carcinoma (HCC) tissues were investigated with PCCT. A histological stain was added to estimate the accuracy of PCCT. The results showed that the fine structures of the microvasculature (measuring 30–100 µm) and thrombi in tiny blood vessels were displayed clearly on imaging the HCC tissues by PCCT. Moreover, density distributions of the thrombi were obtained, which could be reliably used to distinguish malignant from benign thrombi in HCC. In conclusion, PCCT can clearly show the three-dimensional subtle structures of HCC that cannot be detected by conventional absorption-based computed tomography and provides a new method for the imageology of HCC.

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