• Journal of Radiation Protection and Research
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• 제39권3호
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• pp.142-149
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• 2014

한국은 국가건강검진을 시행하여 국민건강증진에 크게 기여하고 있으며 그 수검률 또한 증가하고 있다. 본 연구는 수검률 증가에 따른 방사선검사의 증가가 예상되어 그 이용 빈도(이용량)와 피폭선량을 파악하고자 한다. 본 연구는 2011년 국민건강보험공단 건강검진 분석 자료에서 방사선검사를 분리하여 이용량을 파악하고, UNSCEAR 2008년 보고서의 수록되어 있는 검사별 선량을 적용하여 국가건강검진에서 방사선검사로 인한 피폭선량을 추정한다. 주요 분석결과 2011년 국가건강검진 수검자 1인당 평균 피폭선량은 0.57 mSv로 추정되었고, 최대 11.081 mSv, 최소 0.02 mSv로 추정되었다. 방사선검사의 이용 빈도와 피폭선량은 각각 총 16,005,914건, 6,311.76 person-Sv로, 이중 이용량은 흉부 X선검사가 1,070,569 (69.17%)건으로 가장 높았고, 피폭선량은 위장조영검사가 5,217.94 (82.67%) person-Sv로 가장 높았다. 성 연령별 결과 39세 이하를 제외한 전 연령대에서 여성의 수검비율과 피폭선량이 높았고, 특히 50-54세 여성이 1,674,787 (10.5%)건, 701.59 (11.1%) person-Sv로 가장 높았다. 검사별 선량에서 위장조영검사가 전체 82.67%를 차지하는 만큼 의료상(목적) 반드시 시행하는 경우를 제외하고는 위장내시경검사를 선택하여 수검 받도록 정책적으로 장려하고 외국의 사례와 같이 경제성과 실효성 평가에 따라 폐지된다면 국가건강검진에의 방사선피폭은 현저히 줄어들 것으로 예상한다.

• Journal of Periodontal and Implant Science
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• 제54권1호
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• pp.3-12
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• 2024

Deep learning (DL) offers promising performance in computer vision tasks and is highly suitable for dental image recognition and analysis. We evaluated the accuracy of DL algorithms in identifying and classifying dental implant systems (DISs) using dental imaging. In this systematic review and meta-analysis, we explored the MEDLINE/PubMed, Scopus, Embase, and Google Scholar databases and identified studies published between January 2011 and March 2022. Studies conducted on DL approaches for DIS identification or classification were included, and the accuracy of the DL models was evaluated using panoramic and periapical radiographic images. The quality of the selected studies was assessed using QUADAS-2. This review was registered with PROSPERO (CRDCRD42022309624). From 1,293 identified records, 9 studies were included in this systematic review and meta-analysis. The DL-based implant classification accuracy was no less than 70.75% (95% confidence interval [CI], 65.6%-75.9%) and no higher than 98.19 (95% CI, 97.8%-98.5%). The weighted accuracy was calculated, and the pooled sample size was 46,645, with an overall accuracy of 92.16% (95% CI, 90.8%-93.5%). The risk of bias and applicability concerns were judged as high for most studies, mainly regarding data selection and reference standards. DL models showed high accuracy in identifying and classifying DISs using panoramic and periapical radiographic images. Therefore, DL models are promising prospects for use as decision aids and decision-making tools; however, there are limitations with respect to their application in actual clinical practice.

• Imaging Science in Dentistry
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• 제44권3호
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• pp.199-205
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• 2014

Purpose: This study aimed to investigate the effect of changing the kilovoltage peak (kVp) on the radiographic assessment of dental caries. Materials and Methods: Seventy-five extracted posterior teeth with proximal caries or apparently sound proximal surfaces were radiographed with conventional E-speed films and a photostimulable phosphor system using 60 kVp and 70 kVp for the caries assessment. The images were evaluated by three oral radiologists and compared with the results of the stereomicroscope analysis. Results: No statistically significant difference was found between 60 kVp and 70 kVp for the caries detection, determination of caries extension into dentin, and caries severity in either the conventional or the digital images. Good to very good inter-observer and intra-observer agreements were found for both kilovoltage values on the conventional and digital images. Conclusion: Changing the kilovoltage between 60 kVp and 70 kVp had no obvious effect on the detection of proximal caries or determination of its extension or severity.

• Imaging Science in Dentistry
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• 제43권2호
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• pp.105-109
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• 2013

Purpose: Preoperative radiographic assessment of the mandibular third molars is essential to prevent inferior alveolar nerve damage during extraction. The purpose of this study was to assess the reliability of panoramic signs of association between the roots of teeth and the canal, and to compare the panoramic signs with cone beam computed tomography (CBCT) findings. Materials and Methods: CBCT images of 132 impacted mandibular third molars were evaluated to determine the association of the root to the canal. The CBCT findings were compared with the corresponding panoramic images. Logistic regression analysis was used to define the diagnostic criteria of the panoramic images. Results: Among the panoramic signs, loss of the cortical line was the most frequent radiographic sign predicting association (sensitivity: 79.31). Contact of the tooth with the canal was observed in all cases in which the loss of cortical line of the canal or darkening of the roots was found on the panoramic radiographs. Conclusion: Darkening of the roots and loss of the cortical line on panoramic radiographs might be highly suggestive of the risk of nerve injury.

• 대한족부족관절학회지
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• 제11권1호
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• pp.72-78
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• 2007

Purpose: This study is to analysis the outcome of patient with surgically treated Maisonneuve fracture and find out the factors that might influence the outcome. Material and methods: 20 patients who had surgical treatment due to Maisonneuve fracture between February, 2001 to March, 2005 were studied. The patients were followed for at least 1 year and average follow up period was 25 months. The average age was 41 years, 16 were male and 4 were female. Mechanism of injury according to Rouge-Hansen classification was supination-external rotation. In all cases, percutaneous screw fixation was applied proximal to tibiofibular syndesmosis. The screws were removed after 8 weeks under local anesthesis. Clinical, functional and radiographic results were evaluated. Results: 17 cases (85%) showed satisfying clinical and radiographic results. The mean functional score according to Ankle Scoring System was 91 (83 to 95). Complication occurred in 1 case with underlying systemic disease and 2 cases with initial ankle joint dislocation. Conclusion: Surgical treatment of Maisonneuve fracture showed relatively satisfying result. However, initial injury state and accompanying disease seem to have great effect on the result.

• 제어로봇시스템학회논문지
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• 제5권3호
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• pp.353-362
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• 1999

This paper presents a shape reconstruction method for automatic inspection of the solder joints on PCBs using X-ray. Shape reconstruction from X-ray radiographic image has been very important since X-ray equipment was used for improving the reliability of inspection result. For this purpose there have been lots of previous works using tomography, which reconstructs the correct shape, laminography or tomosynthesis, which are very fast algorithm. Latter two methods show outstanding performance in cross-sectional image reconstruction of lead type component, but they are also known to show some fatal limitations to some kinds of components such as BGA, because of shadow effect. Although conventional tomography does not have any shadow effect, the shape of PCB prohibits it from being applied to shape reconstruction of solder joints on PCB. This paper shows that tomography using Iterative Reconstruction Technique(IRT) can be applied to this difficult problem without any limitations. This makes conventional radiographic instrument used for shape reconstruction without shadow effect. This means that the new method makes cost down and shadow-free shape reconstruction. To verify the effectiveness of IRT, we develop three dimensional model of BGA solder ball, make projection model to obtain X-ray projection data. and perform a simulation study of shape reconstruction. To compare the performance of IRT with that of conventional laminography or tomosynthesis, reconstruction data are reorganized and error analysis between the original model are also performed.

• Maxillofacial Plastic and Reconstructive Surgery
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• 제23권4호
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• pp.332-337
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• 2001

An odontoma is a slow growing and nonaggressive odontogenic tumor composed of enamel, dentin, cementum, and pulp tissue. The etiology of odontomas is unknown, although local trauma, infection, and genetic factors have been suggested. Odontomas are classified as compound odontoma or complex. A 20-year retrospective study was performed on 36 odontomas from the files of the Department of Oral Pathology at Chosun University School of Dentistry. Fifty-six percent of the patients were compound odontoma and 44% were complex odontoma. 56 percent of the patients were female and 44% were male. The odontoma is most often diagnosed in the second decade of life, during routine radiographic examination. The usual presenting symptoms are an impacted or and unerupted tooth, a retained primary tooth. Other less frequent signs and symptoms are pain, swelling, suppuration, foul odor, tooth mobility. In our patients were treated by enucleation of the tumor, and related teeth were treated by surgical extraction or orthodontically assisted eruption.

• 치과방사선
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• 제27권1호
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• pp.17-24
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• 1997

The purpose of the present study was to use digital profile image features and digital image analysis of fixed-dimension bone regions, extracted from standardized periapical radiographs of the maxilla, to determine whether differences exist in alveolar bone of younger women(mean age: 59.23±7.34 years) and just menopaused women(mean age: 59.23±7.34). Periapical films were used from two groups of 20 randomly selected women. None of the subjects had a remarkable medical history. To simplify protocol, we chose one interproximal bone area between the maxillary right canine and lateral incisor for study. Ech film was digitized into a 1312 x 1024 pixel x 8 bit depth matrix by means of a Nikon 35 mm film scanner(LS-35lOAF, Japan) with fixed gain and internal dark current correction to maintain constant illumination. The scanner was interfaced to a Macintosh LC III computer(Apple Computer, Charlotte, N.C.). Area and profile orientation were selected with a NIMH Image 1.37(NIH Research Services Branch, Bethesda, Md.). Histogram features were extracted from each profile and area. The results of this study indicate that mean pixel intensities didn't differ significantly between two groups and there was a high correlarion-coefficient between digitized radiographic profile features and area features.

• International Journal of CAD/CAM
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• 제6권1호
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• pp.105-115
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• 2006

Thickness is a commonly used parameter in product design and manufacture. Its intuitive definition as the smallest dimension of a cross-section or the minimum distance between two opposite surfaces is ambiguous for intricate solids, and there is very little reported work in automatic computation of thickness. We present three generic definitions of thickness: interior thickness of points inside an object, exterior thickness for points on the object surface, and radiographic thickness along a view direction. Methods for computing and displaying the respective thickness values are also presented. The internal thickness distribution is obtained by peeling or successive skin removal, eventually revealing the object skeleton (similar to medial axis transformation). Another method involves radiographic scanning along a viewing direction, with minimum, maximum and total thickness options, displayed on the surface of the object. The algorithms have been implemented using an efficient voxel based representation that can handle up to one billion voxels (1000 per axis), coupled with a near-real time display scheme that uses a look-up table based on voxel neighborhood configurations. Three different types of intricate objects: industrial (press cylinder casting), sculpture (Ganesha idol), and medical (pelvic bone) were used for successfully testing the algorithms. The results are found to be useful for early evaluation of manufacturability and other lifecycle considerations.

• 비파괴검사학회지
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• 제30권5호
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• pp.479-483
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• 2010

초저온 액화가스인 LNG의 저장탱크에 사용되는 9% 니켈강은 Inconel 혹은 Hastelloy 계열 용접봉을 사용하여 용접되며, 용접부는 저합금강과 오스테나이트 스테인리스강의 이종금속 용접부와 유사한 특성을 가지고 있다. 용접부에 대한 방사선투과시험 시 용접조건에 따라 밴드형태의 지시가 방사선투과 필름 상에 나타나곤 한다. 따라서 본 연구에서는 이에 대한 해석을 위하여 재료, 방사선투과시험, 초음파탐상시험, 액체침투탐상시험 및 조직시험을 통하여 의사지시 여부를 확인하였으며, 방사선투과시험 해석 및 밴드형태 지시의 발생 원인을 제시하였다.