WE‐G‐204‐06: Grid‐Line Artifact Minimization for High Resolution Detectors Using Iterative Residual Scatter Correction

Rana, R; Bednarek, Daniel R.; Rudin, Stephen

doi:10.1118/1.4926090

Cited by 3 publications

(4 citation statements)

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“…Compared with contemporary commercial grids with strip‐frequencies from 40 to 80 lines cm −1 , the N35r8h1.7 grid has a low strip frequency. When this grid would be used in stationary with digital image receptors, grid‐line‐removing techniques 3,5–9 might be an optional solution to remove interference of grid‐line artifacts on making diagnosis.…”

Section: Discussionmentioning

confidence: 99%

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The determination of the optimal strip‐thickness of anti‐scatter grids for a given grid ratio and strip height

Zhou

Yin

Tan

et al. 2020

Int J Imaging Syst Tech

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In X‐ray imaging, anti‐scatter grids are used to reduce scatter radiation reaching image receptors, hence improving image quality. Optimization of grid performance is essential for improving image diagnostic quality and minimizing radiation doses to patients. This work investigated the performance of a series of grid designs modeled from the design of typically focused grid with grid ratio 8:1 (r8) and strip height 1.7 mm (h1.7) for high‐energy radiographic applications. Monte Carlo simulation was used to evaluate designs (r8h1.7) which had the strip thickness changed from 6 to 150 μm in 2 μm increments and the interspace distance fixed at 214 μm. The transmissions of radiation in grid materials were modeled by using a regression with radial‐basis‐function‐networks (RBFNS). KSNR was then determined from RBFNS models of radiation transmissions. The optimal strip‐thickness was obtained at the maximum signal‐to‐noise ratio (SNR) improvement factor (KSNR). For high‐energy applications at 100 peak‐kilo‐voltage (kVp) and 30 cm PMMA thickness, the optimal lead‐strip‐thickness was found approximately 74 μm resulting in a strip‐frequency approximately 35 per cm (N35). Using the optimal thickness for imaging condition at 100 kVp and 30 cm thickness, the KSNR would increase by approximately 5.3%. This work showed the existence of optimal strip‐thickness for a series of grids with a given grid‐ratio, strip‐height, strip‐, and interspace materials. The findings are useful and provide guidance to improve grid designs for better performance that will essentially lead to better image quality and better radiation protection for patients.

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Section: Discussionmentioning

confidence: 99%

“…However, gridlines resulted from grids with high‐grid‐frequency, such as 70 lines cm −1 , are still significant and interfere with the visibility of low contrast details 4 . When stationary grids are used with digital image receptors, grid‐line artifacts may be removed by image processing techniques 3,5–9 …”

Section: Introductionmentioning

confidence: 99%

The determination of the optimal strip‐thickness of anti‐scatter grids for a given grid ratio and strip height

Zhou

Yin

Tan

et al. 2020

Int J Imaging Syst Tech

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“…Then each part of the image is corrected individually by iteratively varying the scatter value in the respective section of the scatter profile, to minimize the standard deviation of the grayscale values in that part of the image. In the previous study, we showed that as the grid lines (structure pattern) are removed from the image, the standard deviation of pixel values in the image also goes down 8 . Once all the parts are corrected, they are combined back to form the corrected original image.…”

Section: Methodsmentioning

confidence: 96%

Scatter estimation and removal of anti-scatter grid-line artifacts from anthropomorphic head phantom images taken with a high resolution image detector

et al. 2016

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In radiography, one of the best methods to eliminate image-degrading scatter radiation is the use of anti-scatter grids. However, with high-resolution dynamic imaging detectors, stationary anti-scatter grids can leave grid-line shadows and moiré patterns on the image, depending upon the line density of the grid and the sampling frequency of the x-ray detector. Such artifacts degrade the image quality and may mask small but important details such as small vessels and interventional device features. Appearance of these artifacts becomes increasingly severe as the detector spatial resolution is improved. We have previously demonstrated that, to remove these artifacts by dividing out a reference grid image, one must first subtract the residual scatter that penetrates the grid; however, for objects with anatomic structure, scatter varies throughout the FOV and a spatially differing amount of scatter must be subtracted. In this study, a standard stationary Smit-Rontgen X-ray grid (line density - 70 lines/cm, grid ratio - 13:1) was used with a high-resolution CMOS detector, the Dexela 1207 (pixel size - 75 micron) to image anthropomorphic head phantoms. For a 15 × 15cm FOV, scatter profiles of the anthropomorphic head phantoms were estimated then iteratively modified to minimize the structured noise due to the varying grid-line artifacts across the FOV. Images of the anthropomorphic head phantoms taken with the grid, before and after the corrections, were compared demonstrating almost total elimination of the artifact over the full FOV. Hence, with proper computational tools, anti-scatter grid artifacts can be corrected, even during dynamic sequences.

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“…In previous studies, we reported the results involving a simulated artery block phantom with a uniform frontal head equivalent phantom used as the scattering source to investigate the effectiveness of the method to remove the anti-scatter grid-line artifacts when a grid is used with a Flat Panel Detector (FPD) and high resolution CMOS detector. 6, 7, 8 …”

Section: Methodsmentioning

confidence: 99%

Real time implementation of anti-scatter grid artifact elimination method for high resolution x-ray imaging CMOS detectors using Graphics Processing Units (GPUs)

Rana

Nagesh

Bednarek

et al. 2017

Medical Imaging 2017: Physics of Medical Imaging

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Scatter is one of the most important factors effecting image quality in radiography. One of the best scatter reduction methods in dynamic imaging is an anti-scatter grid. However, when used with high resolution imaging detectors these grids may leave grid-line artifacts with increasing severity as detector resolution improves. The presence of such artifacts can mask important details in the image and degrade image quality. We have previously demonstrated that, in order to remove these artifacts, one must first subtract the residual scatter that penetrates through the grid followed by dividing out a reference grid image; however, this correction must be done fast so that corrected images can be provided in real-time to clinicians. In this study, a standard stationary Smit-Rontgen x-ray grid (line density – 70 lines/cm, grid ratio – 13:1) was used with a high-resolution CMOS detector, the Dexela 1207 (pixel size – 75 micron) to image anthropomorphic head phantoms. For a 15 × 15 cm field-of-view (FOV), scatter profiles of the anthropomorphic head phantoms were estimated then iteratively modified to minimize the structured noise due to the varying grid-line artifacts across the FOV. Images of the head phantoms taken with the grid, before and after the corrections, were compared, demonstrating almost total elimination of the artifact over the full FOV. This correction is done fast using Graphics Processing Units (GPUs), with 7–8 iterations and total time taken to obtain the corrected image of only 87 ms, hence, demonstrating the virtually real-time implementation of the grid-artifact correction technique.

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WE‐G‐204‐06: Grid‐Line Artifact Minimization for High Resolution Detectors Using Iterative Residual Scatter Correction

Cited by 3 publications

References 0 publications

The determination of the optimal strip‐thickness of anti‐scatter grids for a given grid ratio and strip height

The determination of the optimal strip‐thickness of anti‐scatter grids for a given grid ratio and strip height

Scatter estimation and removal of anti-scatter grid-line artifacts from anthropomorphic head phantom images taken with a high resolution image detector

Real time implementation of anti-scatter grid artifact elimination method for high resolution x-ray imaging CMOS detectors using Graphics Processing Units (GPUs)

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