A stationary computed tomography system with cylindrically distributed sources and detectors

Chen, Yi; Xi, Yan; Zhao, Jun

doi:10.3233/xst-140456

Cited by 11 publications

(16 citation statements)

References 32 publications

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“…To deal with this problem, the designed X-ray exit windows are located in the virtual edge of the cube to reduce the room occupied by the chambers as much as possible. Inspired by [ 23 ], the missing projection data can be compensated to a certain extent through linear interpolation. Third, because the detectors collect photons from different fixed focal spots in the MCCT, there is no antiscatter grid at the detectors.…”

Section: Discussionmentioning

confidence: 99%

“…This CT system uses linear CNT X-ray tubes to construct a stationary CT setup and the CNT-based X-ray source contains a dense array of independently controlled electron emission points. Zhao et al [ 23 ] proposed a helical interlaced-source-detector-array CT, which can provide ultrahigh temporal resolution without any mechanical motions. Approximately complete projections were acquired through interpolations.…”

Section: Introductionmentioning

confidence: 99%

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Design and Simulation Study of a CNT-Based Multisource Cubical CT System for Dynamic Objects

et al. 2018

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The purpose of this paper is to design and simulate a new computed tomography (CT) system with a high temporal resolution for dynamic objects. We propose a multisource cubical CT (MCCT) system with X-ray tubes and detectors installed on a cube. Carbon nanotube- (CNT-) based X-ray focal spots are distributed on the twelve edges of the cube. The distribution of X-ray focal spots and detectors completely avoids mechanical movements to scan an object under inspection. CNTs are excellent electron field emitters because the use of a “cold” cathode makes it possible to fabricate a cathode with multiple electron emission points, and the CNT-based X-ray focal spots possess little response time and programmable emission. The proposed rotation-free MCCT system can acquire a high scanning speed when using a high frame rate detector. A three-dimensional (3D) reconstruction algorithm with tensor framelet-based L0-norm (TF-L0) minimization is developed for the simulation study of the MCCT. Simulation experiment results demonstrate the feasibility of the MCCT system.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Design and Simulation Study of a CNT-Based Multisource Cubical CT System for Dynamic Objects

et al. 2018

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“…Schwoebel et al evaluated a prototype linear stationary source for tomosynthesis system, which is comprised of 10 x‐ray source elements . A helical interlaced‐source‐detector array CT architecture utilizing cylindrically distributed sources and detectors array was proposed to achieve fast CT scan . Recently, the feasibility of IGCT system comprised of a ring of source arrays was investigated to obtain better temporal resolution, while the detector array and collimator still need to rotate.…”

Section: Introductionmentioning

confidence: 99%

Stationary computed tomography with source and detector in linear symmetric geometry: Direct filtered backprojection reconstruction

et al. 2020

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Purpose: Inverse-geometry computed tomography (IGCT) could have great potential in medical applications and security inspections, and has been actively investigated in recent years. In this work, we explore a special architecture of IGCT in a stationary configuration: symmetric-geometry computed tomography (SGCT), where the x-ray source and detector are linearly distributed in a symmetric design. A direct filtered backprojection (FBP)-type algorithm is developed to analytically reconstruct images from the SGCT projections. Methods: In our proposed SGCT system, a big number of x-ray source points equally distributed along a straight-line trajectory will sequentially fire in an ultra-fast manner in one side, and an equispaced detector whose total length is comparable to that of the source will continuously collect data in the opposite side, as the object to be scanned moves into the imaging plane. We firstly present the overall design of SGCT. An FBP-type reconstruction algorithm is then derived for this unique imaging configuration. With finite length of x-ray source and detector arrays, projection data from one segment of SGCT scan are insufficient for an exact reconstruction. As a result, in practical applications, dual-SGCT scan whose detector segments are placed perpendicular to each other, is of particular interest and is proposed. Two segments of SGCT together can make sure that the passing rays cover at least 180 degrees for each and every point if carefully designed. In general, however, there exists a data redundancy problem for a dual-SGCT. So a weighting strategy is developed to maximize the use of projection data collected while avoid image artifacts. In addition, we further extend the fan-beam SGCT to cone beam and obtain a Feldkamp-Davis-Kress (FDK)-type reconstruction algorithm. Finally, we conduct a set of experimental studies both in simulation and on a prototype SGCT system and validate our proposed methods. Results: A simulation study using the Shepp-Logan head phantom confirms that CT images can be exactly reconstructed from dual-SGCT scan and that our proposed weighting strategy is able to handle the data redundancy properly. Compared with the rebinning-to-parallel-beam method using the forward projection of an abdominal CT dataset, our proposed method is seen to be less sensitive to data truncation. Our algorithm can achieve 10.64 lp/cm of spatial resolution at 50% modulation transfer functions point, higher than that of the rebinning method which can only reach at 9.42 lp/cm even with extremely fine interpolation. Real experiments of a cylindrical object on a prototype SGCT further prove the effectiveness and practicability of the direct FBP method proposed, with similar level of noise performance to rebinning algorithm. Conclusions: A new concept of SGCT with linearly distributed source and detector is investigated in this work, in which spinning of sources and detectors is no longer needed during data acquisition, simplifying its system design, development, and manufacturing. A direct FBP-...

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“…Besides, there are missing projection data that is at the region of placing X-ray source devices in the source-detector plate, which will result in artifacts in the reconstructed image [14], [15]. Due to the width of the X-ray source device is in millimeter level, which is much higher than the pixel size of the detector, the conventional artifact deduction methods, such as interpolation [16], [17], regularization in iterative reconstruction [18] cannot handle it well. In this regard, we propose a data completion method to compensate the lost projection.…”

Section: Introductionmentioning

confidence: 99%

A Novel Stationary CT Scheme Based on High-Density X-Ray Sources Device

et al. 2020

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With the introduction of cold electron sources such as nanotubes, X-ray sources became small in size so that many sources are installed in array to form stationary CT, which brings benefits of simplicity in mechanism and fast response. However, the nanotube-based X-ray source is still singly packaged and hence density of X-ray sources is limited, which introduces severe sparse-view artifacts and could not be used in practice. With the invention of X-ray sources device based on ZnO nanowires as cold electron emitters, a large amount of X-ray sources is first integrated in a flat panel device. In this study, we design a stationary CT architecture using high-density sources devices, called HD-SCT, and develop corresponding reconstruction algorithm. Specifically, several flat panel detectors and X-ray sources devices are spliced together to form a source-detector plate. Multiple source-detector plates are organized as a polygon that encloses object to complete CT scanning. In HD-SCT, X-ray sources are close to object which can significantly decrease CT device volume. The X-ray beam emitted by each source just cover part of object and the spot sources alternately light to completely scan object. Simultaneously, we propose a reconstruction method for the specific configuration which adopts an iterative algorithm to resolve the reconstruction based on alterative part projections, as well as a novel correction process of projection completion for the shadowed area of placing X-ray source devices. To validate the design of the proposed HD-SCT, we execute a series of simulation experiments, which show that the proposed HD-SCT and corresponding reconstruction method effectively remove the artifacts caused by the embed X-ray source device. The results also disclose that with the increase of density of X-ray sources, the resolution of reconstruction has been dramatically improved, which demonstrates the practical value of introducing high-density X-ray sources device into stationary CT design. INDEX TERMS Stationary CT scheme, high-density X-ray sources devices, source-detector plate, iterative reconstruction.

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A stationary computed tomography system with cylindrically distributed sources and detectors

Cited by 11 publications

References 32 publications

Design and Simulation Study of a CNT-Based Multisource Cubical CT System for Dynamic Objects

Design and Simulation Study of a CNT-Based Multisource Cubical CT System for Dynamic Objects

Stationary computed tomography with source and detector in linear symmetric geometry: Direct filtered backprojection reconstruction

A Novel Stationary CT Scheme Based on High-Density X-Ray Sources Device

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