• Journal of radiological science and technology
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• v.44 no.6
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• pp.607-613
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• 2021

Long-bone examination is mainly used for inspection of the lower extremities. Recently, a long length detector (FXRD-1751S, VIEWORKS, Korea) with three digital detectors attached has been developed. High energy X-rays are used because pelvic areas require high image quality. In this case, X-rays are transmitted a lot in thin areas such as an ankle, and it is not suitable for diagnosing an image. Therefore, this study use copper filters made with 3D printers to increase image quality in the Long-bone inspection. A copper filter was manufactured in consideration of the overall thickness of the lower part. The experiment was conducted in anterior-posterior (AP) and lateral (LAT) positions, depending on the presence or absence of the filter. 5x5 pixels of region of interest (ROI) were selected from the pelvis, knee, and ankle areas. X-rays were irradiated under the conditions of 70 kVp and 40 mAs for AP, 80 kVp, and 63 mAs for lat when without filters, 90 kVp and 80 mAs for AP, 90 kVp and 100 mAs for lat when with filters. signal to noise ratio(SNR) ratio and contrast to noise (CNR) values were measured 1106.38, 14.34 before applying the filter and 1189.32, 70.43 after the filter. For the knee area, 650.44, 97.61 before applying the filter, and 1013.17, 444.24 after applying the filter. For the ankle area, 206.65, 23.68 before applying the filter and 993.50, 136.11 after applying the filter. In the Long-bone examination, SNR and CNR were greatly measured when the filter was applied, confirmed the availability of using the copper additional filter.

• Journal of radiological science and technology
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• v.38 no.3
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• pp.205-211
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• 2015

We evaluated the effectiveness of TL (Time Limit) method by comparing with NTL (Non-time limit) method when it is used for examinations for abdomen Anterior Posterior (AP) in this paper. The evaluation was conducted based on the comparison of dose, and of signal to noise ratio (SNR) and contrast to ratio (CNR) on both methods. The experiments were conducted with XGEO GC 80 (Samsung, Korea), Unfors ThinX RAD (Unfors, Sweden) and Rando Phantom (Alderson research laboratories, USA) and shielding material with the size of $5.5{\times}9{\times}0.1cm^3$. It was set to activate only two upper ionization chambers in automatic exposure control(AEC) mode and the tube-voltage was set to 80kVp. When the exposure time was limited, it is limited to 51 msec. The images both by NTL AEC method and TL AEC method were acquired when with and without attachment of shielding material on the upper ionization chambers. The images were evaluated by SNR and CNR which are the image evaluation methods using 'Image J'. The NTL AEC method showed increases in dose as much as 130.7% at maximum and 80% at minimum than other methods. The TL AEC method showed decreases in mAs and exposure dose than the NTL AEC method as much as 43.8% and 44.4% respectively. There were no significant differences in SNR or CNR for the experiments (($p{\geq}0.05$). Therefore, it is suggested that the TLAEC mode is more effective when examining patients who have high BMI index or a patient with a metallic substance in the body after surgery.

• Proceedings of the Korea Information Processing Society Conference
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• 2012.04a
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• pp.369-372
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• 2012

대사성 골 질환인 골다공증(Osteoporosis)의 조기 진단을 위한 골 밀도를 측정하는 방법이 최근 연구되고 있다. 골 밀도 영상은 이중 에너지 X 선 흡수법에 의해 측정되는데, 영상에 존재하는 잡음은 뼈 영역 추출과 골 밀도 계산에 어려움을 주고 있다. 따라서 본 논문에서는 최근 신호처리 분야에서 폭넓게 사용되고 있는 sparse 표현을 도입하여 X 선 영상의 잡음을 제거하는 방법을 제안한다. 실험을 통해 제안한 잡음 제거 방법의 결과가 기존의 방법에 비해 개선됨을 MSR(Mean to Standard deviation Ratio)과 CNR(Contrast to Noise Ratio)을 통해 확인하였다.

• Journal of the Korean Society of Radiology
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• v.16 no.2
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• pp.169-175
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• 2022

In this study, envisioned a laboratory equipped with virus blocking equipment for chest X-ray examinations of respiratory or droplet-transmitted virus-infected patients, and the material with the least deterioration in X-ray output and image quality among the proven blocking materials that block viruses in the design process. and experimented to find the thickness. As a result, when 1 cm of acrylic was applied, the X-ray output was reduced by only about 3.27 % compared to the absence of the barrier material, the SNR was 40.7 and CNR was 30.9, which was the best. The SSIM index result was analyzed as 0.891, which was analyzed to be implemented as the most similar image compared to the original image. The barrier material applied in the research method was objective in that it used a product approved by the Ministry of Food and Drug Safety. the results of this study are expected to provide useful information when installing X-ray examination facilities for the diagnosis and treatment of respiratory-related virus-infected patients in the future.

• Journal of the Korean Society of Radiology
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• v.11 no.1
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• pp.55-61
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• 2017

There are no recommended test conditions for digital photography in Chest PA examinations. However, each company recommends shooting examinations of the high voltage applied to the previous analog examination. The condition that satisfies the value of 200 ~ 800 which is the recommended Exposure Index value recommended by Philips was selected, and the dose was evaluated by Monte Carlo simulation, and the SNR and CNR were compared. As a result, it was possible to reduce the effective dose up to 77% by controlling the tube voltage, tube current, and additional filter, not the conventional high voltage imaging method. Although there were some differences according to the test conditions, the image evaluation results were similar to the images. We will compare the exposure dose according to changes in tube voltage, tube current, and additional filter at the digital chest radiograph and evaluate the image quality of the image to propose optimal conditions.

• Korean Membrane Journal
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• v.6 no.1
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• pp.55-60
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• 2004

In recent years, an increasing interest in membrane technology has been observed in chemical and environmental industry. Membrane technology has advantages of low cost, energy saving and environmental clean technology comparing to conventional separation processes. Pervaporation is one of new advanced membrane technology applied for separation of azeotropic mixtures, aqueous organic mixtures, organic solvent and petrochemical mixtures. Sodium alginate composite membranes were prepared for the enhancement of long-term stability of pervaporation performance of water-ethanol mixture using pervaporation. Sodium alginate membranes were crosslinked with CaCl$_2$ and coated with polyelectrolyte chitosan to protect washing out of calcium ions from the polymer. The surface structures of PAN and hydrolysed PAN membrane were confirmed by ATR Fourier transform infrared (FT-IR). A field emission scanning electron microscopy (FE-SEM; Jeol 6340F) operated at 15 kV. Concentration profiles for Ca in the membrane surface and membrane cross-section were taken by an energy dispersive X-ray (EDX) analyser (Jeol) attached to the field emission scanning electron microscopy (Jeol 6340F). Pervaporation experiments were done with several operation run times to investigate long-term stability of the membranes.

• Progress in Medical Physics
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• v.19 no.3
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• pp.150-156
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• 2008

An applied technique of contrast enhancement for X-ray image is proposed which is based on combined enhancement of scaling and wavelet coefficients in discrete wavelet transform space. Conventional contrast enhancement methods such as contrast limited adaptive histogram equalization (CLAHE), multi-scale image contrast amplification (MUSICA) and gamma correction were applied on scaling coefficients to enhance the contrast of an original. In order to enhance the detail as well as reduce the blurring caused by up scaling of contrast modified scale coefficients from lower resolution, the sigmoid manipulation function was used to manipulate wavelet coefficients. The contrast detail mammography (CDMAM) phantom was imaged and processed to measure the image line profile of results and contrast to noise ratio (CNR) comparatively. The proposed technique produced better results than direct application of various contrast enhancement methods on image itself. The proposed method can enhance contrast, and also suppress the amplification of noise components in a single process. It could be useful for various applications in medical, industrial and graphical images where contrast and detail are of importance.

• Journal of the Korean Society of Radiology
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• v.14 no.7
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• pp.931-936
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• 2020

This study was conducted to observe the changes in radiation exposure dose and image quality of pediatric patients according to the presence and size of the gonadal shield when using the AEC system. X-ray equipment was used to measure the radiation exposure dose in the abdominal and gonads of the pediatric phantom when no shielding body was used and when three different sizes of shielding body were used, and SNR and CNR were measured through the obtained images. As a result of the study, the radiation exposure dose to the gonads decreased in proportion to the size of the radiation shield, but the radiation exposure dose to the abdomen was rather increased, and the image quality did not change. It is recommended to use a shield with a size optimized for the age, weight, and body size of the pediatric patient so as not to be overexposed by the increased radiation due to the radiation shield due to the use of the AEC System. For this purpose, information about the pediatric patient with the nurse It is believed that exchange is necessary.

• Journal of the Korean Society of Radiology
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• v.18 no.3
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• pp.257-265
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• 2024

In this study, we applied AEC(Auto Exposure Control), which is used in many chest examinations, to evaluate whether medical devices inserted into the body affect the dose and image quality of chest images. After attaching three HIMD(Human implantable medical devices) to the ion chamber, the Monte Carlo methodology-based program PCXMC(PC Program for X-ray Monte Carlo) 2.0 was applied to measure the effective dose by inputting the DAP(Dose Ares Product) value derived from the Pacemaker and CRT and Chemoport Additionally, to evaluate image quality, we set three regions of interest and one noise region on the chest and measured SNR and CNR. The final study results showed significant differences in DAP and Effective dose. There was a significant difference between Pacemaker and CRT when AEC was applied and not applied. (p<0.05) When applied, the dose increased by 37% for Pacemaekr and 52% for CRT. Chemoport showed a 10% increase in effective dose depending on whether AEC was applied, but there was no significant difference. (p>0.05) In the image quality evaluation, there was no significant difference in image quality between all HIMD insertions and AEC applied or not. (p>0.05) Therefore, when the HIMD was inserted into the chest during a chest x ray and overlapped with the ion chamber sensor, the effective dose increased, and there was no difference in image quality even at a low dose without AEC. Therefore, when performing a chest X-ray examination of a patient with a HIMD inserted, it is considered that performing the examination without applying AEC is a method that can be considered to reduce the patient's radiation exposure.

• Journal of the Institute of Electronics and Information Engineers
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• v.53 no.10
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• pp.138-142
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• 2016

Dual-energy digital radiography (DEDR) has been used for detecting lesions within the body using energy subtraction methods. The purpose of this study was to acquire optimal bone and tissue image by changing physical factors such as Tube voltage (kVp) and add filters, and then we compared with the predicted values using SRS-78 program and experimental results. For that purpose, we acquired images according to changes in physical parameters of various materials since we had to acquire the optimal bone and tissue image using energy subtraction. Used phantom consists of aluminum and polymethyl methacrylate (PMMA) and a comparison of image optimization was measured by contrast-to-noise ratio (CNR). In results, first of all, we confirmed that a subtraction image from 50 kVp image and 120 kVp image is optimal bone and tissue image. Also when we added a 10 mm Aluminum add filter, we expected it is a result of the optimal bone and tissue image. Besides, we confirmed these results are consistent with the predicted optimized condition by SRS-78 program.. In conclusion, we indicated that we can acquire optimal bone and tissue image by controling physical factors such as kVp, add filters through this study. Also we expected that DEDR will contribute to the field of medical imaging technology.