Reduction of scattering artifact in multislice CT

Sabo-Napadensky, I.; Amir, O.

doi:10.1117/12.594885

Cited by 8 publications

(3 citation statements)

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“…For each experiment, four reconstructions are calculated: an uncorrected reconstruction, a reconstruction of a narrow scan, a scatter‐corrected reconstruction using a constant scatter estimate, and a reconstruction using the proposed C‐arm iPMSE method. The constant scatter correction method has a parameter C , which is set to 0.5.…”

Section: Methodsmentioning

confidence: 99%

Scatter correction using a primary modulator on a clinical angiography C‐arm CT system

et al. 2017

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Purpose: Cone beam computed tomography (CBCT) suffers from a large amount of scatter, resulting in severe scatter artifacts in the reconstructions. Recently, a new scatter correction approach, called improved primary modulator scatter estimation (iPMSE), was introduced. That approach utilizes a primary modulator that is inserted between the X-ray source and the object. This modulation enables estimation of the scatter in the projection domain by optimizing an objective function with respect to the scatter estimate. Up to now the approach has not been implemented on a clinical angiography C-arm CT system. Methods: In our work, the iPMSE method is transferred to a clinical C-arm CBCT. Additional processing steps are added in order to compensate for the C-arm scanner motion and the automatic X-ray tube current modulation. These challenges were overcome by establishing a reference modulator database and a block-matching algorithm. Experiments with phantom and experimental in vivo data were performed to evaluate the method. Results: We show that scatter correction using primary modulation is possible on a clinical C-arm CBCT. Scatter artifacts in the reconstructions are reduced with the newly extended method. Compared to a scan with a narrow collimation, our approach showed superior results with an improvement of the contrast and the contrast-to-noise ratio for the phantom experiments. In vivo data are evaluated by comparing the results with a scan with a narrow collimation and with a constant scatter correction approach. Conclusions: Scatter correction using primary modulation is possible on a clinical CBCT by compensating for the scanner motion and the tube current modulation. Scatter artifacts could be reduced in the reconstructions of phantom scans and in experimental in vivo data.

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Section: Methodsmentioning

confidence: 99%

Scatter correction using a primary modulator on a clinical angiography C‐arm CT system

et al. 2017

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“…The milliamps or microamps (intensity) are the number of photons emitted per second on a given surface area. For a large fossil sample obtained from a medical XCT, it is recommended to use the maximum power (120-140 kV) and an average intensity to reduce the contribution of a diffusion effect in recorded images called Compton scattering (Glover, 1982;Sabo-Napadensky and Amir, 2005;Johnson, 2012;Ravanfar-Haghighi et al, 2014). Two acquisitions of our sample were collected with a kV greater than 400: the skulls of Ursus arctos and of Ursus maritimus, using the laboratory XCT system of the University of Texas (see Supplementary Data).…”

Section: X-ray Computed Tomography Acquisitionmentioning

confidence: 99%

Toward an “Ancient” Virtual World: Improvement Methods on X-ray CT Data Processing and Virtual Reconstruction of Fossil Skulls

Pérez‐Ramos

Figueirido

2020

Front. Earth Sci.

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This article focuses on new virtual advances to solve technical problems usually encountered by paleontologists when using X-ray computed tomography (XCT), such as (i) the limited scanning envelope (i.e., field of view of CT systems/machines) to acquire data on large structures; (ii) the use in the same study of biological objects acquired with different types of computed tomography systems (medical and laboratory XCTs and laboratory high-resolution XµCT) and therefore different resolutions; and (iii) matrix removal within the fossil (e.g., cranial cavities, intratrabecular cavities, among other cavities). All these problems are very common in paleontology, and therefore, solving them is important to save effort and the time invested in data processing. In this article, we propose various solutions to tackle these issues, based on new technical advances focused on improving and processing the images obtained from XCT. Other aspects include image filtering and histogram calibration to remove background noise and artifacts. Such artifacts can result from dense mineral inclusion occurring during the fossilization process or derived from anthropogenic restoration of the sample. Accordingly, here, we provide a protocol to acquire data on samples with size that exceed the scanning envelope of the X-ray tomography machine, joining the parts with enough accuracy, and we propose the use of the interpolation "bicubic" method. Moreover, using this method, it is possible to use medical/laboratory XCT data together with XµCT data and therefore opening new ways to manipulate the acquired data within the image stack. Another advantage is the use of plugins for quantitative analysis, which require data with isometric voxels, such as the plugin BoneJ of the software ImageJ. We also deal with the problem of removing the exogenous material that usually fills the internal cavities of fossils by means of using filters based on edge detection by gradient. Applying this method, it is possible to segment the non-bony matrix parts more quickly and efficiently. All of this is exemplified using five fossil skulls belonging to the cave bear group (Ursus spelaeus sensu lato), an iconic fossil species from the Pleistocene of Eurasia.

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“…In conventional x-ray CT this problem is mostly dealt with hardware solutions such as high Z materials anti-scatter grids which are part of the detecting system, preventing the scattered photons from reaching the detector. There are also numerous attempts to solve the issue by using software corrections [1][2][3]. Both are complicated, do not solve the problem completely and may eventually induce new artifacts.…”

Section: Scattermentioning

confidence: 99%

Research and development of a dedicated collimator for 14.2 MeV fast neutrons for imaging using a D-T generator

Sabo-Napadensky¹,

Weiss-Babai²,

Gayer³

et al. 2012

J. Inst.

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One of the main problems in neutron imaging is the scattered radiation that accompanies the direct neutrons that reach the imaging detectors and affect the image quality. We have developed a dedicated collimator for 14.2 MeV fast neutrons. The collimator optimizes the amount of scattered radiation to primary neutrons that arrive at the imaging plane. We have used different materials within the collimator in order to lower the scattered radiation that arrives at the scanned object. The image quality and the signal to noise ratios that are measured show that a mixture of BORAX (Na 2 B 4 O 7 •10H 2 O) and water in the experimental beam collimator give the best results. We have used GEANT4 to simulate the collimator performance, the simulations predict the optimized material looking on the ratios of the scattered to primary neutrons that contribute in the detector. We present our experimental setup, report the results of the experimental and related simulation studies with neutrons beam generated by a 14.2 MeV D-T neutron generator.

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Reduction of scattering artifact in multislice CT

Cited by 8 publications

References 0 publications

Scatter correction using a primary modulator on a clinical angiography C‐arm CT system

Scatter correction using a primary modulator on a clinical angiography C‐arm CT system

Toward an “Ancient” Virtual World: Improvement Methods on X-ray CT Data Processing and Virtual Reconstruction of Fossil Skulls

Research and development of a dedicated collimator for 14.2 MeV fast neutrons for imaging using a D-T generator

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