• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2007년도 제28회 춘계학술대회논문집
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• pp.17-21
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• 2007

초음파를 이용한 로켓 모타의 비파괴검사는 X-ray 검사에 비하여 경제성이 우수하고, 미접착 등의 결함 검출이 우수한 편이다. 그리고 전용 시설 없이 현장에서 실시간으로 검사가 가능하며 방사선 작업에 비하여 안전한 방법이다. 본 논문에서는 초음파 다중반사에 의한 추진제/라이너 미접착 검출 기법에 대하여 실험 및 이론적 모델링으로 분석하였다. 실험 결과, 추진제/라이너 미접착의 신호가 정상 접착과 구별되는 뚜렷한 신호 차이를 보였으며, 실험에서 측정한 신호와 이론적 모델링 신호가 대체적으로 일치하였다.

• Imaging Science in Dentistry
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• 제42권4호
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• pp.213-217
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• 2012

Purpose: This study was performed to evaluate the uniqueness and reliability of the frontal sinuses by comparing various patterns of frontal sinus as observed on Waters' radiographs for individual identification. Materials and Methods: Three Waters' radiographs of 100 individuals, taken on day one, after 6-8 months, and one radiograph with a slight variation in angulation, to mimic conditions out in the field or during autopsy. Three observers were randomly given radiographs from all there packets for comparisons and identification, by the method of superimposition and individual uniqueness. Results: The comparative identification by superimposition of the frontal sinus was 100% positive. The size, shape, unilateral or bilateral presence, absence, and septa were observed to be unique in each case; neither had the measurements changed over a period of time. Conclusion: The need to establish a reliable, low-cost, and easily reproducible method for human identification prompted the elaboration of technical, precise, and accessible parameters, such as the evaluation of the area, asymmetry, and shape of the frontal sinus. Comparison among each of the frontal sinuses of the 100 people in the sample revealed that no two sinuses are the same, that is, the sinus is unique to each individual.

• 대한족부족관절학회지
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• 제18권3호
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• pp.124-128
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• 2014

Purpose: The purpose of this study was to assess the treatment outcomes and prognosis of Lisfranc joint fracture and dislocation according to the mechanism of injury and treatment method. Materials and Methods: Twenty six patients with Lisfranc fracture-dislocation who had been treated surgically were included in this retrospective study. The patients were divided into two groups according to mechanism of injury: direct crushing injury (16 patients) and indirect rotational or compressive injury (10 patients). The patients were also divided into three groups according to the surgical methods. The parameters used were radiographic evaluation, patients' subjective satisfaction levels, length of hospital stay, and the American Orthopaedic Foot and Ankle Society (AOFAS) midfoot score. Statistical analysis was performed. Results: The mean postoperative AOFAS midfoot score was 78.7. The mean length of stay was 39.6 days. Statistically significant differences in subjective satisfaction, AOFAS midfoot score, and length of hospital stay were observed between the two groups (p<0.05). However, no significance differences were observed between the three groups who were divided according to the different surgical methods (p>0.05). Conclusion: Mechanism of trauma and the severity of soft-tissue injury were significant prognostic factors affecting the surgical outcomes of Lisfranc joint fracture and dislocation.

• 한국콘텐츠학회논문지
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• 제15권7호
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• pp.289-299
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• 2015

본 연구의 목적은 디지털방사선시스템의 영상 품질을 비교하고 평가함에 있다. 영상의 정량적인 분해능을 나타내는 변조전달함수, 노이즈 특성을 나타내는 잡음력 스펙트럼을 이용하여 영상 품질평가를 하였다. IEC61267 선질을 사용하여 IEC62220-1에서 제시하는 기하학적인 조건과 실제 임상에서 사용되어지는 기하학적인 조건을 사용하여 부가필터 및 그리드, 임상선량을 이용하여 edge 팬텀을 사용하여 MTF값을 측정하였다. Grid, Filter, SID, kVp, mAs에 따른 MTF 결과는 임상조건 100, 180cm 와 IEC62220-1 기하학적인 조건 150cm에서 MTF 공간주파수 측정값은 비슷하게 나타났으며, 오히려 임상조건 100, 180cm에서 공간주파수가 높은 경우도 있었다. NPS 결과는 선량이 증가함에 따라 감소함을 나타내었다. IEC61267 선질을 이용한 영상품질평가에서는 IEC62220-1기하학적인 조건을 이용한 품질평가보다 임상조건 기하학적인 조건을 사용한 영상의 품질이 좋았다. IEC 와 임상조건에서의 MTF와 NPS는 크게 차이가 나지 않았음을 알 수 있었다. 그러므로 향후 IEC 표준에서 제시하는 영상품질 평가보다는 임상 조건을 적용한 영상품질 평가방법을 적용하기 위해서 부가필터사용 유 무, 그리드사용 유 무, SID변화, 선질, 선량 등의 파라메터를 적절히 이용하여 가장 적은 선량으로 공간분해능이 좋고, NPS가 감소하는 방법들을 찾는다면 향후 실제 임상에서 사용되고 있는 디지털방사선시스템을 최적의 품질로 유지할 수 있는 참고 자료로 활용될 수 있을 것으로 사료된다.

• Clinics in Shoulder and Elbow
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• 제11권2호
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• pp.137-142
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• 2008

목적: 잠김 압박 금속판(LCP)을 이용한 상완골 근위부 골절의 수술적 치료에 대한 임상적, 방사선적 치료 결과를 평가해보고자 하였다. 대상 및 방법: 2005년 1월부터 2007년 4월까지 상완골 근위부 골절에 대해 LCP를 이용해 치료받고 12개월 이상 추시가 가능했던 24예를 대상으로 하였으며, 남자는 8예, 여자는 16예이었다. 평균 연령은 68.9세(33~90)이었다. 임상적 결과는 Neer의 기능적 평가 방법을, 방사선적 결과는 골 유합 시기 및 경간각을 이용한 Paavolainen의 방법으로 평가하였다. 결과: 평균 골 유합 기간은 11.9주(8~15)이었다. Neer의 기능적 평가상, 만족 이상의 결과를 보인 경우는 21예(87%)이었고, Paavolainen의 방법에 의한 방사선적 결과가 양호 이상인 경우는 22예(91%)이었다. 3예(13%)에서 금속 실패, 무혈성 골 두 괴사, 관절 강직의 합병증이 각각 발생하였다. 결론: 상완골 근위부 골절에 대해 LCP를 이용한 내고정술은 비교적 양호한 임상적, 방사선적 결과 및 적은 합병증을 보여, 상완골 근위부 골절의 수술적 치료에 유용한 방법 중 하나로 판단된다.

• Imaging Science in Dentistry
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• 제30권3호
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• pp.155-158
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• 2000

1. 일반방사선사진과 칼라화한 방사선사진의 비교에서 각각 필름에서 진단을 시행할 때 ROC해석법에서는 true positive fraction (TPF), false positive fraction (FPF)를 매개변수로 하고 있으므로 우선 두가지 필름형태에 대해 각각 따로 다음과 같이 평가한다. 2. 판정기준 병변없다 A, 거의 없다 B, 모르겠다 C, 거의 있다 D, 있다 E 먼저 일반방사선사진에서 실제로 병소가 총있는 것이 50, 총없는 것이 50인데 위 판정기준 각각에 대해(equation omitted) 3. 곡선만들기 a.횡축은 FPF 종축은 TPF로 한 그래프를 plot를 한다. sensitivity 17/50 specificity 26/50 accuracy 43/100 b. 곡선만들기 프로그램을 이용하여 곡선을 만들시에는 TPF를 a에 입력하고 PFP를 b에 입력한다. 이 plot을 그릴 수 있는 프로그램은 http://www.members.tripod.co.kr/jdakim 또는 http://www.chosun.ac.kr/∼jdakim의 홈페이지내 공개자료실에서 다운 받으실 수 있습니다. (equation omitted) 이 프로그램에서 입력할 a, b의 값은 (equation omitted) 위와같이 입력하여 얻어진 일반방사선사진에서의 판독 결과 얻어진 곡선이 그래프에서 곡선이 된다. 이와 같은 커브를 컬러화한 사진 판독에서 똑같이 시행하여 ROC곡선(윗곡선)을 만든 다음 두 곡선을 비교하여 아래면적이 더 큰 쪽이 병소 판독에 우수하다고 결론짓는다.

• Maxillofacial Plastic and Reconstructive Surgery
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• 제35권2호
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• pp.88-93
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• 2013

Purpose: Maxillary sinus elevation has been widely used to enable insertion of endosseous implants in severely resorbed maxilla. Maxillary sinusitis after this procedure was considered to be the major drawback, therefore, preoperative evaluation of paranasal sinus is considered to be important. In order to evaluate the condition of the sinus, we used Waters' projection. In this study, asymptomatic patients were evaluated by Waters' view, and compared to timing to assess the sinus cavity. Methods: The retrospective study was based on 14 patients who were performed sinus elevation surgery in Seoul National University Dental Hospital. These patients did not show any signs of maxillary sinusitis. These patients were taken Waters' view at preoperative, postoperative 1 day, 3 months, 6 months. In Waters' view, presence of air fluid level, radiopacity of sinus wall, or radiopacity of entire maxillary sinus were evaluated. The density, and sinus dimension changes were assessed using Adobe Photoshop CS5$^{(R)}$ (Adobe Systems Inc., San Jose, CA, USA). Results: Findings of Waters views in patients with clear maxillary sinus at preoperative time were followed by elevated sinus floor with transplanted bone, mucosal swelling, and air fluid level. At postoperative 3 months, and 6 months, the radiographic findings were similar to preoperative state. By contrast, patients with preoperative mucosal swelling, or haziness in sinus cavity showed radiopacity entire sinus in Waters' view. In cases of the patients who were treated with simultaneous treatment to mucosal swelling, good status of sinus cavity were found. Conclusion: Although Waters' projections provide the limited information, and is less sensitive method compared with computed tomography, it is simple, easy, and economical method to assess of maxillary sinus. We suggest using Waters' view as radiographic routine tool for evaluation of sinus condition, especially in the sinus elevation surgery.

• Imaging Science in Dentistry
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• 제53권3호
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• pp.193-198
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• 2023

Purpose: Artificial intelligence (AI) is poised to play a major role in medical diagnostics. Periodontal disease is one of the most common oral diseases. The early diagnosis of periodontal disease is essential for effective treatment and a favorable prognosis. This study aimed to assess the effectiveness of AI in diagnosing periodontal bone loss through radiographic analysis. Materials and Methods: A literature search involving 5 databases (PubMed, ScienceDirect, Scopus, Health and Medical Collection, Dentistry and Oral Sciences) was carried out. A specific combination of keywords was used to obtain the articles. The PRISMA guidelines were used to filter eligible articles. The study design, sample size, type of AI software, and the results of each eligible study were analyzed. The CASP diagnostic study checklist was used to evaluate the evidence strength score. Results: Seven articles were eligible for review according to the PRISMA guidelines. Out of the 7 eligible studies, 4 had strong CASP evidence strength scores (7-8/9). The remaining studies had intermediate CASP evidence strength scores (3.5-6.5/9). The highest area under the curve among the reported studies was 94%, the highest F1 score was 91%, and the highest specificity and sensitivity were 98.1% and 94%, respectively. Conclusion: AI-based detection of periodontal bone loss using radiographs is an efficient method. However, more clinical studies need to be conducted before this method is introduced into routine dental practice.

• 대한의용생체공학회:의공학회지
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• 제41권4호
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• pp.165-171
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• 2020

In this study, it focuses on the development of radiographic devices for patellar imaging. On the previous X-ray examination of patella and patellofemoral joint, it analyzed the problems which could affect the results: unstable patients' pose, radiation exposure, and deterioration of image quality. The purpose of the research is to propose a future use of a developed device with an explanation of the process, function, and advantage of the device including the methods. The device is developed to focus on the diagnosis of the longitudinal and longitudinal fractures of the patella and patella/femoral joint, displacement such as dislocation, bone formation, stenosis of the patella/femorla joint, and cartilage wear. Due to the patient's anxious posture, it caused a shaking image, overlapping structures, and etcs, these factors challenge to diagnose accurately. In addition, the existing Settegast method and Hughston method, which are most frequently performed in the hospital field, are not suitable for the presence or absence of features or dislocation due to the heavy load on the patella of the patient. The developed device requires patients in a lying position and placing only their leg on the device, it increases the conveniences of the examination and decreases unnecessary radiation exposure of the patient except the patellar examination area. Moreover, one of the systems in the device fixes the detector, where the patients no longer need to hold the detector nor be in unstable posture, but describes the structure of the patella/femoral joint more clearly. Hoping the device will apply to more patients.

• The Korean Journal of Legal Medicine
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• 제42권4호
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• pp.141-145
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• 2018

There have been many radiographic studies on age estimation that evaluate reduction in size of dental pulp cavity with secondary dentin formation. The Paewinsky method reported high accuracy in estimating ages by measuring the width of the pulp cavity in panoramic radiographs. The aim of this study was to evaluate the application of the Paewinsky method to digital periapical radiographs. This study was conducted on 103 cases that reported to the Section of Human Identification of the National Forensic Service. The age was calculated by applying the Paewinsky method that measures the root and pulp canal width at three points in a tooth. The estimation results were compared with those calculated by the Johanson method. When the Paewinsky models were applied to digital periapical radiographs, the errors were significantly greater as compared to the original study. The errors of the maxillary second premolar and mandibular lateral incisor were greater than those of the maxillary central incisor, lateral incisor, mandibular canine, and first premolar. Furthermore, errors of the age estimation models in level C were greater than those in levels A and B. This study could be a reference for the application of the Paewinsky method to digital periapical radiographs.