• Journal of Magnetics
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• 제21권4호
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• pp.593-598
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• 2016

In order to reduce the amount of noise component in X-ray imaging system, various reduction techniques were frequently used in the field of diagnostic imaging. Although the previous techniques -such as median, Wiener filters and Anscombe noise reduction technique - were able to reduce the noise, the edge information was still damaged. In order to cope with this problem, total variation (TV) noise reduction technique has been developed and researched. The purpose of this study was to evaluate and compare the image quality using normalized noise power spectrum (NNPS) and contrast-to-noise ratio (CNR) through simulations and experiments with respect to the above-mentioned noise reduction techniques. As a result, not only lowest NNPS value but also highest CNR values were acquired using a TV noise reduction technique. In conclusion, the results demonstrated that TV noise reduction technique is proved as the most practical method to ensure accurate denoising in X-ray imaging system.

• 대한방사선기술학회지:방사선기술과학
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• 제14권2호
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• pp.55-55
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• 1991

I reduced overexposed X-Ray film image with farmer reduction method and $KMnO_4$ reduction method. The results are as follows : 1. In farmer reduction method, there appears linear decreasing film image density. 2. In $KMnO_4$ reduction method, there appears over proportional reduction. 3. When red prussiate is compared with $KMnO_4$ reduction method, the latter shows more intense reduction. 4. If the reduction solution isn't used within 10 minutes after dilution, it becomes oxidized and the ability is decreased remarkably.

• 대한디지털의료영상학회논문지
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• 제13권4호
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• pp.185-189
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• 2011

To assess the prevalence of various radiological reduction methods for childhood intussusception in training hospitals by means of a nationwide phone survey, and to demonstrate recent trends in this area by comparing the findings with those obtained in a survey conducted. $BaTiO_3$ system was prepared by using fabrication of classical conditioning ceramics. Polycrystalline and surface structure characteristics of the specimens were measured by X-ray diffraction, SEM(Scanning Electron Microscopy) and EDAX (Energy Dispersive Spectrometer), respectively.

• 대한방사선기술학회지:방사선기술과학
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• 제6권1호
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• pp.85-89
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• 1983

• 대한방사선기술학회지:방사선기술과학
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• 제44권3호
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• pp.225-229
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• 2021

The digital image such as medical X-ray and nuclear medicine field mainly contains noise distribution. The noise degree in image degrades image quality. That is why, the noise reduction algorithm is efficient for medical image field. In this study, we confirmed effectiveness of application for median modified Wiener filter (MMWF) algorithm for noise reduction in PET/MR image compared with median filter image, which is used as conventional noise redcution algorithm. The Jaszczak PET phantom was used by using 18F solution and filled with NaCl+NiSO4 fluids. In addition, the radioactivity ratio between background and six spheres in the phantom is maintained to 1:8. In order to mimic noise distribution in the image, we applied Gaussian noise using MATLAB software. To evlauate image quality, the contrast to noise ratio (CNR) and coefficient of variation (COV) were used. According to the results, compared with noise image and images with MMWF algorithm, the image with MMWF algorithm is increased approximately 33.2% for CNR result, decreased approximately 79.3% for COV result. In conclusion, we proved usefulness of MMWF algorithm in the PET/MR images.

• 대한방사선기술학회지:방사선기술과학
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• 제46권3호
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• pp.207-217
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• 2023

Image noise reduction algorithm performs important functions in light microscopy. This study aims to systematically review the research trend of types and performance evaluation methods of noise reduction algorithm in light microscopic images. A systematic literature search of three databases of publications from January 1985 to May 2020 was conducted; of the 139 publications reviewed, 16 were included in this study. For each research result, the subjects were categorized into four major frameworks-1. noise reduction method, 2. imaging technique, 3. imaging type, and 4. evaluation method-and analyzed. Since 2003, related studies have been conducted and published, and the number of papers has increased over the years and begun to decrease since 2016. The most commonly used method of noise reduction algorithm for light microscopy images was wavelet-transform-based technology, which was mostly applied in basic systems. In addition, research on the real experimental image was performed more actively than on the simulation condition, with the main case being to use the comparison parameter as an evaluation method. This systematic review is expected to be extremely useful in the future method of numerically analyzing the noise reduction efficiency of light microscopy images.

• BMB Reports
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• 제47권10호
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• pp.575-580
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• 2014

In this study, we investigate whether arsenite-induced DNA damage leads to p53-dependent premature senescence using human glioblastoma cells with p53-wild type (U87MG-neo) and p53 deficient (U87MG-E6). A dose dependent relationship between arsenite and reduced cell growth is demonstrated, as well as induced ${\gamma}H2AX$ foci formation in both U87MG-neo and U87MG-E6 cells at low concentrations of arsenite. Senescence was induced by arsenite with senescence-associated ${\beta}$-galactosidase staining. Dimethyl- and trimethyl-lysine 9 of histone H3 (H3DMK9 and H3TMK9) foci formation was accompanied by p21 accumulation only in U87MG-neo but not in U87MG-E6 cells. This suggests that arsenite induces premature senescence as a result of DNA damage with heterochromatin forming through a p53/p21 dependent pathway. p21 and p53 siRNA consistently decreased H3TMK9 foci formation in U87M G-neo but not in U87MG-E6 cells after arsenite treatment. Taken together, arsenite reduces cell growth independently of p53 and induces premature senescence via p53/p21-dependent pathway following DNA damage.

• 한국방사선학회논문지
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• 제8권5호
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• pp.217-223
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• 2014

본 연구에서 Phantom에 고 밀도 물질이 삽입 된 CT 영상을 재구성 하여 방사선 치료 계획 시 선량 분포에 대한 평가를 하고자 하였다. Gammex 467 Tissue Characterization Phantom을 사용하여 인체 조직과 유사한 영상을 획득하였고 Titanium을 삽입하여 금속물로 인한 인공허상을 발생시켜 영상을 획득하였다. 획득한 영상은 Metal Artifact Reduction for Orthopedic Implants (O-MAR)를 이용하여 영상을 재구성 하였고 전산화 치료계획 시스템을 이용하여 체적을 분석 하고 선량 분포를 추출하였다. $MapCHECK^{TM}$을 이용하여 선형가속기의 광자선 선량 분포를 측정하여 계획한 선량 분포와 비교 분석 하였다. 비교 분석 결과 Titanium으로 인한 인공허상이 발생 되었을 때 O-MAR를 적용한 체적은 BR-12 Breast는 16.8 % 그리고 LV 1 Liver는 40.2 % 증가하였고 선량 분포는 O-MAR를 적용하기 전의 선량 분포 보다 1.4 에서 1.6 % 높게 나타났다. 결론적으로 금속물로 발생된 인공허상 O-MAR를 적용하여 가능한 제거하고 치료계획에 이용해야 오류를 줄일 수 있을 것으로 사료된다.

• 대한방사선기술학회지:방사선기술과학
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• 제47권3호
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• pp.205-211
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• 2024

Currently, with the development of technologies, X-ray examinations for medical examinations at hospital is increasing. This study was conducted to help reduce radiation exposure by measuring the exposure dose received by pediatric patients and the spatial dose of the X-ray room. Dosimeters were installed in the eyeball, thyroid gland, breast, gonads and 4 directions at a distance of 30 cm, 40 cm, 50 cm from the phantom. The dose was measured ten times each, before, and after the application of the bismuth shield under the examination conditions of the head, chest, and abdomen of pediatric patients. Under the condition of head examination, when a shielding was applied, the dose reduction rate was 68.58% for the eyeball, 72.88% for the thyroid, 84.2% for the breast, and 72.36% for the gonad. The chest examination showed reductions of 19.56% eyeball, 56.98% thyroid, 1.21% breast, and 0.68% gonad. The abdominal examination showed reduction rates of 2.6% eyeball, 10.67% thyroid, 19.85% breast, and 82.02% gonad. Spatial dose decreased by 62.25% at 30 cm, 61.16% at 40 cm, and 68.68% at 50 cm. When the bismuth shield was applied, there was a decrease in dose across all examinations, as well as a reduction in spatial dose. Continued research on the use of bismuth shields will help radiological technologists achieve their goal of dose reduction.

• Journal of Magnetics
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• 제22권1호
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• pp.55-59
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• 2017

The purpose of this study was to quantitatively evaluate image quality using intensity profile, coefficient of variation (COV), and peak signal to noise ratio (PSNR) with respect to noise reduction techniques in the ultrasound images. For that purpose, we compared with the median filter, Rudin-Osher-Fatemi (ROF), Anscombe and proposed patch group prior based denoising (PGPD) techniques. To evaluate image quality, the Shepp-Logan phantom and the ultrasound image were acquired using simulation and experiment, respectively. According to the results, the difference of intensity profile using PGPD technique is lowest compared with original Shepp-Logan phantom. In simulation, the measured COV was 0.249, 0.198, 0.198, 0.177, and 0.080 using noisy, median, ROF, Anscombe and PGPD technique, respectively. Also, in experimental image, the measured COV was 0.245, 0.230, 0.231, 0.242 and 0.187 using noisy, median, ROF, Anscombe and PGPD technique, respectively. Especially, when we used PGPD technique, the PSNR has highest value in both simulation and experiment. In this study, we performed simulation and experiment study to compare various denoising techniques in the ultrasound image. We can expect the PGPD technique to improve in medical diagnosis with excellent noise reduction.