The patient motion can damage the quality of computed tomography images, which are typically acquired in cone-beam geometry. The rigid patient motion is characterized by six geometric parameters and are more challenging to correct than in fan-beam geometry. We extend our previous rigid patient motion correction method based on the principle of locally linear embedding (LLE) from fan-beam to cone-beam geometry and accelerate the computational procedure with the graphics processing unit (GPU)-based all scale tomographic reconstruction Antwerp toolbox. The major merit of our method is that we need neither fiducial markers nor motion-tracking devices. The numerical and experimental studies show that the LLE-based patient motion correction is capable of calibrating the six parameters of the patient motion simultaneously, reducing patient motion artifacts significantly.
X-ray tensor tomography is a promising imaging modality for probing the micro structure of a sample by reconstructing
small-angle scattering densities in different scattering directions. However, the current x-ray grating technique still faces
an obstacle when a divergent x-ray beam from a point x-ray source propagates through a large object and reaches large
planar gratings. In this situation, tensor interior tomography is essential to perform the image reconstruction over a
region of interest (ROI) in the object. Therefore, we propose interior tensor tomography with 2D gratings to extract dark
field images isotropically. Our numerical results demonstrate that the proposed methods are promising for reconstruction
of local images from truncated dark field projection data.
Recent advances in X-ray imaging technologies have paved the way for use of energy-discriminating photon-counting
detector arrays. These detectors show promise in clinical and preclinical applications. Multi-energy or spectral CT images
can be visualized in multi-colors. Despite the advantages offered by the spectral dimension of acquired data, higher image
resolution is still desirable, especially in challenging tasks such as on-site studies of resected pathological tissues. Here we
propose to enhance image resolution of a spectral X-ray imaging system by partially blocking each detector element with
an absorption grating (for reduced aperture), commonly used for Talbot-Lau interferometry. After acquiring X-ray data at
an initial grating-detector configuration, the grating is shifted to expose previously blocked portions so that each
measurement contains new information. All the acquired data are then combined into an augmented system matrix and
subsequently reconstructed using an iterative algorithm. Our proof of concept simulations are performed with MCNP6.1
code and the experiment was performed using a Hamamatsu microfocus X-ray source, an absorption grating, and an Xray
camera. Our results demonstrate that the gratings commonly used for x-ray phase-contrast imaging have a utility for
super-resolution imaging performance.
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