• 대한디지털의료영상학회논문지
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• 제9권2호
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• pp.17-21
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• 2007

The purpose to recognize change of average pixel value of acquisition image by control panel's density and right set up method of speed (sensitivity) and exposure dose(mAs) change that dose in purpose digital flatpanel-detector. X -ray generator DHF-158H2(Hitachi, Japan). Detector CXDI 4OG(Canon, Japan), 12 : 1 grid and exposure ray 135 kVp, 250 mA, 10 ms. focus-detector distance 180 cm and used AEC mode. DICOM reflex analysis program used image J that is digital reflex analysis program that offer in United States America National Health Center(National Institutes of Health : NlH) phantom used chest phantom(Anthromorphic : Flukebrome.medicaI USA). An experiment chest phantom that consist by formation equivalence material use because density value( -3${\sim}$+3) in X-ray control panel and seep that is speed step(slow, medium, fast) each control experimentalize. image analysis reflex neted through an experiment using image j each image compare. These was change in dose according to slow, medium, fast and density's change in an experiment result. According to detector sensitivity and density condition set, dose was relationship dissimilarity 500% from 200%. The dose came highest when is density +3 to slow. and dose more increases gray scale's extent could know that rise. Could know whether how equipment set is important through this experiment. cause of disease which change by digital radiography system forward is thought to increase more, it is considered that suitable education by this and continuous interest about equipment need absolutely.

• 한국의료질향상학회지
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• 제20권1호
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• pp.60-73
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• 2014

Objectives: This study aims at decreasing spatial dose rate through work improvement whilst spatial dose rate is the cause of increasing personal exposure dose which occurs in the process of handling radioisotope. Methods: From February 2013 until July 2013, divided into "before" and "after" the improvement, spatial dose rate in laboratory of nuclear medicine was measured in gamma image room, PET/CT-1 image room, and PET/CT-2 image room as its locations. The measurement time was 08:00, 12:00 and 17:00, and SPSS 21.0 USA was opted for its statistical analysis. Result: The spatial dose rate at distribution worktable, injection table, the entrance to the distribution room, and radioisotope storage box, which had showed high spatial dose rate, decreased by more than 43.7% a monthly average. The distribution worktable, that had showed the highest spatial dose rate in PET/CT-1 image room, dropped the rate to 42.3% as of July. The injection table and distribution worktable in the PET/CT-2 image room also showed the decline of spatial dose rate to 89% and 64.4%, respectively. Conclusion: By improving distribution process and introducing proper radiation shielding material, we were able to drop the spatial dose rate substantially at distribution worktable, injection table, and nuclide storage box. However, taking into account of steadily increasing amount of radioisotope used, strengthening radiation related regulations, and safe utilization of radioisotope, the process of system improvement needs to be maintained through continuous monitoring.

• 핵의학기술
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• 제17권1호
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• pp.71-75
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• 2013

현재 PET/CT 검사에서 저선량 CT를 이용한 감쇠 보정을 사용하고 있다. 하지만 환자 호흡으로 인한 횡격막 부근의 저선량 CT 영상과 Emission 영상의 불일치로 감쇠 보정영상에서 Artifact가 발생하는 경우가 있다. 본 연구는 보정방법 중 CTAC Shift를 이용하여 환자의 호흡에 의한 Artifact의 감소를 연구했다. 2012년 3월부터 9월까지 PET/CT Discovery 600 (GE Healthcare, MI, USA) 장비를 이용하여 호흡에 의한 Artifact가 발생한 환자 30명을 대상으로 했다. Artifact가 발생한 환자는 횡격막 부분을 추가검사하였고, 전신 검사 시 Artifact가 발생한 영상을 CTAC Shift를 이용하여 보정했다. Artifact 발생 영상, 추가 검사영상, CTAC Shift 보정 영상의 육안적 평가는 핵의학 전문의 1명과 5년 이상 근무한 방사선사 4명에 의해 1-5점으로 나누어 평가했다. 또한 각 영상의 표준섭취화 계수를 ANOVA를 이용하여 비교했다. Artifact 발생 영상에 비해 추가 검사 영상과 CTAC Shift 보정 영상은 육안적 평가에서 상대적으로 높은 점수를 받았다. 추가 검사 영상과 CTAC Shift 보정 영상은 표준섭취화 계수의 ANOVA 결과, 높은 상관관계를 갖고 있으며, 유의한 차이를 보이지 않았다. PET/CT 검사 시 환자의 호흡에 의한 Artifact가 발생 할 경우 추가 검사로 인한 검사 시간이 증가하여 환자의 불편 뿐 아니라 피폭도 증가한다. 하지만 추가 검사 없이 CTAC Shift를 이용하여 보정된 영상을 획득한다면 불필요한 피폭 및 추가 검사도 감소하며, 정확한 진단에 도움을 줄 것으로 사료된다.

• 치과방사선
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• 제29권2호
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• pp.387-396
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• 1999

In dentistry. RadioVisioGraphy was introduced as a first electronic dental x-ray imaging modality in 1989. Thereafter. many types of direct digital radiographic system have been produced in the last decade. They are based either on charge-coupled device(CCD) or on storage phosphor technology. In addition. new types of digital radiographic system using amorphous selenium. image intensifier etc. are under development. Advantages of digital radiographic system are elimination of chemical processing, reduction in radiation dose. image processing, computer storage. electronic transfer of images and so on. Image processing includes image enhancement. image reconstruction. digital subtraction, etc. Especially digital subtraction and reconstruction can be applied in many aspects of clinical practice and research. Electronic transfer of images enables filmless dental hospital and teleradiology/teledentistry system. Since the first image management and communications system(IMACS) for dentomaxillofacial radiology was reported in 1992. IMACS in dental hospital has been increasing. Meanwhile. researches about computer-assisted diagnosis, such as structural analysis of bone trabecular patterns of mandible. feature extraction, automated identification of normal landmarks on cephalometric radiograph and automated image analysis for caries or periodontitis. have been performed actively in the last decade. Further developments in digital radiographic imaging modalities. image transmission system. imaging processing and automated analysis software will change the traditional clinical dental practice in the 21st century.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제14권3호
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• pp.1043-1064
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• 2020

A kind of Subjective Imaging Effect Assessment (SIEA) method and its applications on intelligent imaging terminal design in engineering site are presented. First, some visual assessment indices are used to characterize the imaging effect: the image brightness, the image brightness uniformity, the color image contrast, the image edge blur, the image color difference, the image saturation, the image noise, and the integrated imaging effect index. A linear weighted function is employed to carry out the SIEA computation and the Analytic Hierarchy Process (AHP) technique is used to estimate its weights. Second, a SIEA software is developed. It can play images after the settings of assessment index or assessment reaction time, etc. Third, two cases are used to illustrate the application effects of proposed method: the image enhancement system design for surveillance camera and the imaging environment perception system design for intelligent lighting terminal. A Prior Sequential Stimulus (PSS) experiment is proposed to improve the evaluation stability of SIEA method. Many experiment results have shown the proposed method can realize a stable system design or parameters setting for the intelligent imaging terminal in engineering site.

• Advances in nano research
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• 제12권2호
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• pp.185-195
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• 2022

Deep learning is another field of artificial intelligence (AI) utilized for computer aided diagnosis (CAD) and image processing in scientific research. Considering numerous mechanical repetitive tasks, reading image slices need time and improper with geographical limits, so the counting of image information is hard due to its strong subjectivity that raise the error ratio in misdiagnosis. Regarding the highest mortality rate of Lung cancer, there is a need for biopsy for determining its class for additional treatment. Deep learning has recently given strong tools in diagnose of lung cancer and making therapeutic regimen. However, identifying the pathological lung cancer's class by CT images in beginning phase because of the absence of powerful AI models and public training data set is difficult. Convolutional Neural Network (CNN) was proposed with its essential function in recognizing the pathological CT images. 472 patients subjected to staging FDG-PET/CT were selected in 2 months prior to surgery or biopsy. CNN was developed and showed the accuracy of 87%, 69%, and 69% in training, validation, and test sets, respectively, for T1-T2 and T3-T4 lung cancer classification. Subsequently, CNN (or deep learning) could improve the CT images' data set, indicating that the application of classifiers is adequate to accomplish better exactness in distinguishing pathological CT images that performs better than few deep learning models, such as ResNet-34, Alex Net, and Dense Net with or without Soft max weights.

• 대한디지털의료영상학회논문지
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• 제9권1호
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• pp.7-15
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• 2007

고정식 초점형 격자가 적용된 비정질 실리콘 평판형 검출기에서 초점-격자간 중심변위와 두부 팬텀의 검출기내 위치 변위가 영상 특성에 미치는 영향을 조사하여, 디지털 의료영상 장비의 올바른 사용 방법을 제안하고자 한다. 고정식 초점형 격자를 적용한 비정질 실리콘 평판형 검출기에서 두부 팬텀을 사용하여 초점-격자간 중심 변위와 두부 팬텀의 위치 변위에 따라 영상을 획득 하였다. 획득된 영상을 NIH(Image J) 영상 분석 프로그램을 이용하여 동일 영역에서의 픽셀값(Pixel value), 히스토그램(Histogram), 도면형상(plot profile), 표면도(Surface plot)등을 분석하고, 표준 촬영 영상과 비교 하였다. 초점-격자간 측 방향 중심 변위와 초점-격자와 두부 팬텀의 이중 변위는 수평, 대각선으로 증가할수록 픽셀의 평균값과 표준편차값이 비례적으로 감소하였다. 또한 높은 픽셀값의 빈도수가 상당히 감소하여 영상의 대조도를 저하시켰고, 변위가 증가할수록 영상 왜곡현상도 증가하였다. 다음으로 두부 팬텀 위치 변위의 픽셀 평균값은 큰 변화가 없었으나 수평, 대각선으로 증가할수록 높은 픽셀값의 빈도수가 감소하는 양상을 보여 영상의 대조도가 저하 되었다. 디지털 검출기의 넓은 관용도와 후처리 능력은 영상의 화소 잡음이 증가하여도 방사선사들이 인지하지 못할 수 있다. 따라서 방사선사는 격자가 장착된 디지털 검출기에서 화소 잡음을 증가시키는 촬영 요인들을 정확히 인지하여 검사에 임해야 할 것이다.

• 보건의료산업학회지
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• 제5권4호
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• pp.149-159
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• 2011

The purpose of this research is to provide an available basis for marketing strategy by defining the cause-effect relation between the service level of staff members in dental clinic and purchasing behavior of the customers. This study was done in 10 days from November 2, 2009 to November 11, 2009 and the total 172 copies were used for the analysis. As a result of the correlation analysis, a significant positive correlation among all the measured variables was found. As a result of the structural model analysis, I found that the fair service among the variables of the service level significantly affects the building of relationship and the hospital image. The building of relationship and the hospital image significantly affect the positive oral spread. The building of relationship significantly affects the repurchase intentions but the hospital image does not affects the repurchase intentions. To sum up the result of this study, I found that the fair service and the building of relationship with patients are important variables in order to attract new patients and maintain existing customers. I recommend that the hospital continues to motivate staffs through internal marketing and conduct regular trainings. It is necessary to have patients satisfied with broadening responsibility and authority and set marketing strategy for the relationship with patients.

• Clinical Endoscopy
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• 제56권5호
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• pp.553-562
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• 2023

Colonoscopy plays an important role in reducing the incidence and mortality of colorectal cancer by detecting adenomas and other precancerous lesions. Image-enhanced endoscopy (IEE) increases lesion visibility by enhancing the microstructure, blood vessels, and mucosal surface color, resulting in the detection of colorectal lesions. In recent years, various IEE techniques have been used in clinical practice, each with its unique characteristics. Numerous studies have reported the effectiveness of IEE in the detection of colorectal lesions. IEEs can be divided into two broad categories according to the nature of the image: images constructed using narrow-band wavelength light, such as narrow-band imaging and blue laser imaging/blue light imaging, or color images based on white light, such as linked color imaging, texture and color enhancement imaging, and i-scan. Conversely, artificial intelligence (AI) systems, such as computer-aided diagnosis systems, have recently been developed to assist endoscopists in detecting colorectal lesions during colonoscopy. To gain a better understanding of the features of each IEE, this review presents the effectiveness of each type of IEE and their combination with AI for colorectal lesion detection by referencing the latest research data.

• Journal of Korean Neurosurgical Society
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• 제46권4호
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• pp.365-369
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• 2009

Objective : Susceptibility-weighted image (SWI) is a sensitive magnetic resonance image (MRI) technique to detect cerebral microbleeds (MBLs). which would not be detected by conventional MRI. We performed SWI to detect MBLs and investigated its usefulness in the evaluation of mild traumatic brain injury (MTBI) patients. Methods : From December 2006 to June 2007, twenty-one MTBI patients without any parenchymal hemorrhage on conventional MRI were selected. Forty-two patients without trauma were selected for control group. According to the presence of MBLs, we divided the MTBI group into MBLs positive [SWI (+)] and negative [SWI (-)] group. Regional distribution of MBLs and clinical factors were compared between groups. Results : Fifty-one MBLs appeared in 16 patients of SWI (+) group and 16 MBLs in 10 patients of control group [control (+)], respectively. In SWI (+) group, MBLs were located more frequently in white matters than in deep nucleus different from the control (+) group (p<0.05). Nine patients (56.3%) of SW (+) group had various neurological deficits (disorientation in 4, visual field defect in 2, hearing difficulty in 2 and Parkinson syndrome in 1). Initial Glasgow Coma Scale (GCS)/mean Glasgow Outcome Scale (GOS) were $13.9{\pm}1.5/4.7{\pm}0.8$ and $15.0{\pm}0.0/5.0{\pm}0.0$ in SWI (+) and SWI (-) groups, respectively (p<0.05). Conclusion : Traumatic cerebral MBLs showed characteristic regional distribution, and seemed to have an importance on the initial neurological status and the prognosis. SWI is useful for detection of traumatic cerebral MBLs, and can provide etiologic evidences for some post-traumatic neurologic deficits which were unexplainable with conventional MRI.