C-arm CT is movable and plays an important role in clinical surgical treatment. This paper proposes a new image reconstruction method for C-arm computed tomography (CT) using the advantages of backprojection filtratio...
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C-arm CT is movable and plays an important role in clinical surgical treatment. This paper proposes a new image reconstruction method for C-arm computed tomography (CT) using the advantages of backprojection filtration (bpf) algorithm. It first collects the projection data in a short scan, then rearranges the collected projection data into parallel projection data, and finally achieves the 3D image reconstruction in C-arm CT based on the two-step Hilbert transform method. At the same projection data acquisition frequency, compared with the commonly used FDK algorithm in C-arm CT, the advantage of the proposed method is that it only requires the projection data within a short scan, reducing radiation dose by nearly half. In addition, unlike the original bpf algorithm, the scanning angle integration interval in the backprojection of the proposed method is fixed, which improves the reconstruction efficiency and parallelism. Its reconstruction efficiency is nearly twice that of the FDK algorithm. The results of simulation and real data experiments have demonstrated the effectiveness of this proposed method.
作者:
Zou, JingChen, HaoZhang, QiyangYankangXia, DanTianjin Univ
State Key Lab Precis Measurement Technol & Instru Tianjin 300072 Peoples R China Northeastern Univ
Sino Dutch Biomed & Informat Engn Sch Shenyang 110004 Peoples R China Chinese Acad Sci
Shenzhen Inst Adv Technol Inst Biomed & Hlth Engn Paul Lauterbur Ctr Biomed Imaging Res Shenzhen 518055 Peoples R China
Multi-GPUs accelerated bpf algorithm is developed for improving computational efficiency. Three major acceleration techniques are introduced: (1) dividing reconstructed volume into subsets vertically which reduces the...
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Multi-GPUs accelerated bpf algorithm is developed for improving computational efficiency. Three major acceleration techniques are introduced: (1) dividing reconstructed volume into subsets vertically which reduces the computational cost on the boundary term between parallel chords;(2) transposed method is used to avoid low efficiency of access in global memory which is caused by different chords selection;(3) optimized memory allocation scheme is adopted. Experimental data are used to evaluate the image quality and reconstruction time. It takes only 4.118 s to reconstruct a volume image of 512 x 512 x 512 with 360 projection data of 512 x 512 on dual NVIDIA Tesla C2070 cards. Added the time consuming on data read, transfer and storage part, the complete reconstruction process could be finished in less than 9 s. In particular, bpf-based ROI-reconstruction for cone beam Ortho-CT shows promising application prospect.
A mathematical derivation was conducted to illustrate that exact 3D image reconstruction could be achieved for z-homogeneous phantoms from data acquired with 2D general trajectories using the back projection filtratio...
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A mathematical derivation was conducted to illustrate that exact 3D image reconstruction could be achieved for z-homogeneous phantoms from data acquired with 2D general trajectories using the back projection filtration (bpf) algorithm. The conclusion was verified by computer simulation and experimental result with a circular scanning trajectory. Furthermore, the effect of the non-uniform degree along z-axis of the phantoms on the accuracy of the 3D reconstruction by bpf algorithm was investigated by numerical simulation with a gradual-phantom and a disk-phantom. The preliminary result showed that the performance of bpf algorithm improved with the z-axis homogeneity of the scanned object.
In many applications of circular cone-beam computed tomography (CT), it is common that the reconstructed specimens are plate-like. In this paper, a novel method is presented to reconstruct plate-like specimens in a su...
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In many applications of circular cone-beam computed tomography (CT), it is common that the reconstructed specimens are plate-like. In this paper, a novel method is presented to reconstruct plate-like specimens in a super-short scan, thus reducing imaging time and increasing practical CT system throughput. The algorithm of the proposed method is an improved backprojection-filtration (bpf) algorithm using an integral operator with a fixed integral interval. The results of numerical simulation and real data reconstructions show that the proposed method is a good choice for reconstructions of plate-like specimens, because not only can it yield images with a quality comparable to those obtained with existing algorithms, but it can also reduce imaging time and increase CT system throughput.
To reduce the radiation dose in dental computed tomography (CT), backprojection-filtration (bpf) algorithm is the preferred choice as it can reconstruct images from truncated data within limited scanning angle, thereb...
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To reduce the radiation dose in dental computed tomography (CT), backprojection-filtration (bpf) algorithm is the preferred choice as it can reconstruct images from truncated data within limited scanning angle, thereby reducing radiation dose and avoiding irradiation to the brain. However, the integral interval of backprojection is variable for every PI-line which causes the calculation efficiency and parallel performance to be low. In this paper, the tent bpf method (T-bpf) was developed, which was performed by firstly rearranging the cone-beam data to tent-like parallel-beam data, and then applying the proposed bpf-type algorithm to reconstruct images from the rearranged data. T-bpf turns the variable integral interval of backprojection into fixed integral interval, which means the reconstruction efficiency and the parallel performance of T-bpf are improvements over those of the original bpf algorithm. The experiments of numerical simulation and real data reconstruction show that the reconstruction efficiency of T-bpf is faster than the original bpf algorithm and the FDK algorithm in the case of comparable reconstruction quality. The results demonstrate that the proposed T-bpf is good at achieving fast low-dose reconstruction from truncated projection data in dental CT.
In various applications of circular cone-beam computed tomography (CT), it is common that the reconstructed object is big and cannot be covered by the field of view (FOV) due to the restriction of the width of the X-r...
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In various applications of circular cone-beam computed tomography (CT), it is common that the reconstructed object is big and cannot be covered by the field of view (FOV) due to the restriction of the width of the X-ray beam and the size of the detector. Thus, we consider a scanning configuration in which the X-ray beams only cover half of the object and the cone-beam projection data are acquired from an asymmetrically positioned half-sized detector. The acquired cone-beam projection data are truncated at every view angle, which does not satisfy the conventional reconstruction condition that the projection data cannot be transversely truncated. If an explicit data rebinning process is not invoked, this data acquisition configuration will play havoc with many known cone-beam image reconstruction algorithms. In this paper, we apply a recently-developed back projection filtration (bpf) algorithm in circular cone-beam CT and an observation that a correct back projection image can be formed by combining the projection data from different view angles, and then develop an algorithm to reconstruct 3D images for the half-covered scanning configuration. Numerical simulations and real data reconstruction experiments are conducted to validate the proposed reconstruction algorithm.
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