The meaning of interior tomography

Wang, Ge

doi:10.1109/icassp.2011.5947670

Cited by 19 publications

(31 citation statements)

References 136 publications

(262 reference statements)

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“…This inherently impedes the clinical workflow and elevates the imaging dose, greatly limiting its clinical use; (2) the overall image quality (e.g., signal-to-noise ratio, SNR) of 4D-CBCT is still inferior to that of a standard 3D-CBCT (referred as 1-min scan hereafter), let alone the planning CT; (3) 4D-CBCT usually adopts a full-fan mode to maximize the angular sampling. Nonetheless, the associated small field-of-view (FOV) (e.g., 25 cm in diameter) usually cannot cover the whole thorax/abdomen, leading to truncation problem, 17,18 and the truncated 4D-CBCT images cannot serve the purpose of dose calculations due to missing anatomies outside the FOV; and (4) the HU of 4D-CBCT images is inaccurate due to scatter contaminations. The factors mentioned here are usually coupled together.…”

Section: Introductionmentioning

confidence: 99%

A hybrid reconstruction algorithm for fast and accurate 4D cone-beam CT imaging

et al. 2014

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Purpose: 4D cone beam CT (4D-CBCT) has been utilized in radiation therapy to provide 4D image guidance in lung and upper abdomen area. However, clinical application of 4D-CBCT is currently limited due to the long scan time and low image quality. The purpose of this paper is to develop a new 4D-CBCT reconstruction method that restores volumetric images based on the 1-min scan data acquired with a standard 3D-CBCT protocol. Methods: The model optimizes a deformation vector field that deforms a patient-specific planning CT (p-CT), so that the calculated 4D-CBCT projections match measurements. A forward-backward splitting (FBS) method is invented to solve the optimization problem. It splits the original problem into two well-studied subproblems, i.e., image reconstruction and deformable image registration. By iteratively solving the two subproblems, FBS gradually yields correct deformation information, while maintaining high image quality. The whole workflow is implemented on a graphic-processing-unit to improve efficiency. Comprehensive evaluations have been conducted on a moving phantom and three real patient cases regarding the accuracy and quality of the reconstructed images, as well as the algorithm robustness and efficiency. Results: The proposed algorithm reconstructs 4D-CBCT images from highly under-sampled projection data acquired with 1-min scans. Regarding the anatomical structure location accuracy, 0.204 mm average differences and 0.484 mm maximum difference are found for the phantom case, and the maximum differences of 0.3-0.5 mm for patients 1-3 are observed. As for the image quality, intensity errors below 5 and 20 HU compared to the planning CT are achieved for the phantom and the patient cases, respectively. Signal-noise-ratio values are improved by 12.74 and 5.12 times compared to results from FDK algorithm using the 1-min data and 4-min data, respectively. The computation time of the algorithm on a NVIDIA GTX590 card is 1-1.5 min per phase. Conclusions: High-quality 4D-CBCT imaging based on the clinically standard 1-min 3D CBCT scanning protocol is feasible via the proposed hybrid reconstruction algorithm.

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Section: Introductionmentioning

confidence: 99%

A hybrid reconstruction algorithm for fast and accurate 4D cone-beam CT imaging

et al. 2014

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“…We consider the general problem of recovering a function on a region of interest Ω µ ⊂ R d using information from the local Radon transform. In the two-dimensional setting, this corresponds to the interior tomography problem, where one assumes that line integrals passing through the region of interest are known, while the others are unknown [17]. Our reconstruction method is based on the identities…”

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confidence: 99%

“…For the reconstruction of an image I from its Radon transform RI, we use the differentiated backprojection [7,15,17,19,23]. The reconstruction formulas are given in the introduction, where the backprojection operator…”

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confidence: 99%

Interior Tomography Using 1D Generalized Total Variation. Part I: Mathematical Foundation

Ward¹,

Lee²,

Ye³

et al. 2015

SIAM J. Imaging Sci.

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Abstract. Motivated by the interior tomography problem, we propose a method for exact reconstruction of a region of interest of a function from its local Radon transform in any number of dimensions. Our aim is to verify the feasibility of a one-dimensional reconstruction procedure that can provide the foundation for an efficient algorithm. For a broad class of functions, including piecewise polynomials and generalized splines, we prove that an exact reconstruction is possible by minimizing a generalized total variation seminorm along lines. The main difference with previous works is that our approach is inherently one-dimensional and that it imposes less constraints on the class of admissible signals.Within this formulation, we derive unique reconstruction results using properties of the Hilbert transform, and we present numerical examples of the reconstruction.

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“…This may help improve image quality in some systems. Another option to improve resolution is to combine conventional tomography with known-subregion-based interior tomography (Wang and Yu 2013). Mathematically speaking, tomography produces the reconstruction of a function F from a large number of line integrals of F. Conventional tomography is a global procedure because the standard convolution formulae for reconstruction at a given point require the integrals over all lines within the plane containing that point.…”

Section: Discussionmentioning

confidence: 99%

Imaging in 3D under pressure: a decade of high-pressure X-ray microtomography development at GSECARS

Wang

Rivers

2016

Prog. in Earth and Planet. Sci.

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The high-pressure X-ray microtomography (HPXMT) apparatus has been operating at the GeoSoilEnviroCARS (GSECARS) bending magnet beamline at the Advanced Photon Source since 2005. By combining the powerful synchrotron X-ray source and fast switching between white (for X-ray diffraction) and monochromatic (for absorption imaging) modes, this technique provides the high-pressure community with a unique opportunity to image the three-dimensional volume, texture, and microstructure of materials under high pressure and temperature. The ability to shear the sample with unlimited strain by twisting the two opposed anvils in the apparatus allows shear deformation studies under extreme pressure and temperature to be performed. HPXMT is a powerful tool for studying the physical properties of both crystalline and non-crystalline materials under high pressure and high temperature. Over the past 10 years, continuous effort has been put into technical development, modifications to improve the overall performance, and additional probing techniques to meet users' needs. Here, we present an up-to-date report on the HPXMT system, a brief review of some of its many exciting scientific applications, and a discussion of future developments.

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The meaning of interior tomography

Cited by 19 publications

References 136 publications

A hybrid reconstruction algorithm for fast and accurate 4D cone-beam CT imaging

A hybrid reconstruction algorithm for fast and accurate 4D cone-beam CT imaging

Interior Tomography Using 1D Generalized Total Variation. Part I: Mathematical Foundation

Imaging in 3D under pressure: a decade of high-pressure X-ray microtomography development at GSECARS

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