• 대한방사선기술학회지:방사선기술과학
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• 제42권3호
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• pp.167-173
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• 2019

The Cobey method and the modified Cobey method are most commonly used in clinical practice. Therefore, the purpose of this study was to investigate the radiological differences between Cobey and modified Cobey and provide radiographic information about changes of hindfoot image with X-ray entrance center and tube angle change in modified Cobey. This study was performed on foot and ankle phantom. First, for image comparison of Cobey and modified Cobey, the images obtained by applying the same X-ray entrance center to the ankle joint were compared and analyzed. Second, in the modified Cobey, the X-ray entrance center is set as ankle joint and lateral malleolus. The X-ray tube angle was varied from $10^{\circ}$ to $40^{\circ}$ at $5^{\circ}$ intervals for each X-ray entrance center. The images obtained by varying the X-ray tube angle from $10^{\circ}$ to $40^{\circ}$ at intervals of $5^{\circ}$ for each X-ray entrance center were compared and analyzed. The irradiation conditions were the same with 110 kVp, 200 mA, 10 ms, and 110 cm of source - image receptor distance (SID). Image evaluation was performed by two radiologists. Measurements were made on the lateral point, middle point, and calcaneus width based on a hypothetical line parallel to the calcaneal tuberosity. Data were analyzed by using descriptive statistics as the mean of the distance to each measurement location. The modified Cobey was longer than the Cobey by an average of 3 to 4 mm lateral and medial points, and the calcaneus width was similar (ICC = 0.939). In modified Cobey method, when the X-ray entrance center is ankle joint, the lateral point is about 3 mm and the medial point is about 4.3 mm longer than lateral malleolus. Also, when the X-ray tube angle is more than $20^{\circ}$, the degree of distortion is large. The ICCs for the lateral, medial point, and calcaneus width were 0.998, 0.961, and 0.997, respectively, as the X-ray entrance center and tube angle were changed. There was no significant difference between Modified Cobey and Cobey. Modified Cobey showed no need to compensate the $20^{\circ}$ detector angle of the Cobey. In addition, we suggest that tube angle should be limited within $20^{\circ}$ when modified Cobey is performed.

• 한국방사선학회논문지
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• 제13권5호
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• pp.757-763
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• 2019

최근 넓은 동적 범위 특성을 제공하는 평판 디텍터 개발을 바탕으로 의료보건 환경이 디지털화되고 있는 현 시점에서 적절한 필터 두께의 재설정이 요구되고 있으나, 현 임상에서는 기존 아날로그 시스템에서 연구된 정보를 바탕으로 NCRP에서 제안한 권고 기준을 이용하고 있다. 이에 본 연구에서는 디지털방사선 촬영에서 알루미늄 필터를 이용하여 환자선량 최적화와 더불어 선량크리프의 최소화 가능성을 고찰하였다. 연구 결과, 알루미늄 필터의 두께를 증가함에 따라 유사한 선예도를 가지는 의료영상을 획득 시 피폭되는 피부입사선량을 최대 19.3% 저감할 수 있는 것으로 나타났으나, 영상학적 관점에서 중요한 해상력이 1.01 lp/mm의 큰 변화가 분석되었다. 이러한 해상력의 변화는 X선 빔 경화 현상으로 인하여 피사체에서 발생하는 산란선이 증가하기 때문으로 사료되며, 산란 열화 인자를 통하여 산란선량에 의한 영향이 증가하는 것을 정량적으로 검증하였다. 하지만, 최근 개발되어 광범위하게 적용되고 있는 평판 디텍터는 방사선에 대한 민감도가 높고 넓은 동적 범위 특성을 가지므로 필터 두께에 따라 산란선의 비율에 대한 증가분과 대응하여 적정한 해상력을 유지할 수 있을 것으로 사료되며, 더 나아가 피폭선량 저감을 통해 선량크리프를 최소화 할 수 있을 것으로 기대된다.

• 한국지능정보시스템학회:학술대회논문집
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• 한국지능정보시스템학회 2001년도 The Pacific Aisan Confrence On Intelligent Systems 2001
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• pp.378-382
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• 2001

The purpose of this study was to develop an expert system supporting the diagnosis of diffuse interstitial lung disease by high resolution computed tomography. CLIPS(C language integrated production system) with rule-based reasoning was used to develop the system. Development of expert system had three stages knowledge acquisition, knowledge representation, and reasoning. Knowledge was obtained and integrated, from tables and figure legends of a representative textbook in the domain of this expert system, High-Resolution CT of the Lung, by Webb WR, Mueller NL, and Naidich DP. The acquired knowledge was analyzed to form a knowledge base. Overlapping knowledge was eliminated, similar pieces of knowledge were combined and professional terms were defined. The most important knowledge of findings was then selected for each disease. After groupings of combined findings were made, disease groups were analyzed sequentially to determine final diagnoses. The system was based upon the input of 69 diseases, 185 findings, 73 conditions, 387 status, and 62 rules. The system was set up to determine the diagnoses of diseases from the combination of findings using forward reasoning. In an empirical trial, the system was applied to support the diagnosis of 40 cases of diffuse interstitial lung diseases. The performance of two doctors with support of the system was compared to that of another two doctors without support of the system. The two doctors with the support of the system made more accurate diagnoses than the doctors without the support of the system. The system is believed to be useful for the diagnosis of rare diseases and for cases with many possible differential diagnoses. In conclusion, an expert system supporting the high resolution computed tomographic diagnosis of diffuse interstitial lung disease was developed and the system is thought to be useful for medical practice.

• Clinical and Experimental Pediatrics
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• 제59권11호
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• pp.425-431
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• 2016

The waist-to-height ratio (WHtR), calculated by dividing the waist circumference (WC) by height, has recently gained attention as an anthropometric index for central adiposity. It is an easy-to-use and less age-dependent index to identify individuals with increased cardiometabolic risk. A WHtR cutoff of 0.5 can be used in different sex and ethnic groups and is generally accepted as a universal cutoff for central obesity in children (aged ${\geq}6$ years) and adults. However, the WHtR has not been validated in preschool children, and the routine use of WHtR in children under age 6 is not recommended. Prospective studies and meta-analysis in adults revealed that the WHtR is equivalent to or slightly better than WC and superior to body mass index (BMI) in predicting higher cardiometabolic risk. In children and adolescents, studies have shown that the WHtR is similar to both BMI and WC in identifying those at an increased cardiometabolic risk. Additional use of WHtR with BMI or WC may be helpful because WHtR considers both height and central obesity. WHtR may be preferred because of its simplicity and because it does not require sex- and age-dependent cutoffs; additionally, the simple message 'keep your WC to less than half your height' may be particularly useful. This review article summarizes recent publications on the usefulness of using WHtR especially when compared to BMI and WC as a screening tool for obesity and related cardiometabolic risks, and recommends the use of WHtR in clinical practice for obesity screening in children and adolescents.

• 한국전문물리치료학회지
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• 제24권4호
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• pp.54-59
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• 2017

Background: Light touch cue is a sensory input that could potentially help in the control of posture. The immediate stimulatory effect of light touch cues using a cane during gait is associated with postural stability. This strategy can help post-stroke individuals regain their ability to perform the sit-to-stand (STS) transfer safely. Objects: The effects of light grip on postural control during the STS transfer in post-stroke subjects were investigated. Methods: Eleven participants (6 men, 5 women) with hemiplegia due to stroke were recruited in the study. The subjects with hemiparesis performed STS transfer in three randomly assigned conditions (1) without a cane (2) light grip with a cane (3) strong grip with a cane. Results: The difference in weight-bearing distribution between the left and right feet, when the subjects were instructed to stand up, was $52.73{\pm}2.13%$ without a cane, $42.75{\pm}3.26%$ with a strong grip, and $43.00{\pm}2.55%$ with a light grip (p<.05). The rate of rise in force indicates the peak power provided by subjects during their STS transfers. The rate of rise in force was statistically significantly lower without a cane than that with a light grip or a strong grip (p<.05). The subjects' centers of pressure sway on the mediolateral side during STS transfers statistically significantly declined with a light grip or a strong grip when compared to those without a cane (p<.05). Conclusion: When the subjects with hemiparesis used a cane during STS transfers, their duration, center of pressure sway, and difference in weight-bearing distribution were all reduced. The subjects also exhibited similar results during STS transfers with a cane gripped lightly. This result may provide guidelines for the use of assistive devices when patients with hemiparesis practice STS transfers in clinical settings.

• 디지털콘텐츠학회 논문지
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• 제17권4호
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• pp.287-293
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• 2016

시간, 공간, 금전적인 문제 때문에 실습이 쉽지 않은 학문들이 있다. 특히 의료교육은 장소와 시간의 제약이 특히 심하며 cadaver(카드버:인체해부 실습용 시체)를 통해 이루어지기 때문에 어려움이 많다. 그 대안으로 다양한 가상 수술방법이 존재하지만 장비가 고가이거나 구하기 쉽지 않기 때문에 어려운 문제가 발생한다. 이러한 문제점의 해결 방법으로 3D-Virtual Reality(3D가상현실)를 활용하여 실제와 유사한 환경을 제공하고자 한다. 일반적으로 컴퓨터의 Interface(인터페이스)로 키보드와 마우스를 사용하지 않고 Oculus Rift(오큘러스 리프트)와 Leap Motion(립 모션)를 사용함으로써 더욱더 현실감을 느낄 수 있어 실습교육비용을 절감함으로써 실습교육에 대한 효과를 극대화 할 수 있다. 본 논문에서는 두개의 Device(디바이스)인 Oculus Rift(오큘러스 리프트)와 Leap Motion(립 모션)를 이용하여 3D가상 수술 시스템을 구축하고 실습할 수 있는 제안으로 의료교육인 수술교육에 대치하여 효율성을 높이는 방식을 제안하였고, 이는, 다른 Simulation(시뮬레이션)이 활용 가능한 학문분야에 까지 확장할 수 있을 것으로 사려된다.

• 대한치과교정학회지
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• 제46권5호
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• pp.310-322
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• 2016

Objective: The aim of this study was to determine the optimal loading conditions for pure intrusion of the six maxillary anterior teeth with miniscrews according to alveolar bone loss. Methods: A three-dimensional finite element model was created for a segment of the six anterior teeth, and the positions of the miniscrews and hooks were varied after setting the alveolar bone loss to 0, 2, or 4 mm. Under 100 g of intrusive force, initial displacement of the individual teeth in three directions and the degree of labial tilting were measured. Results: The degree of labial tilting increased with reduced alveolar bone height under the same load. When a miniscrew was inserted between the two central incisors, the amounts of medial-lateral and anterior-posterior displacement of the central incisor were significantly greater than in the other conditions. When the miniscrews were inserted distally to the canines and an intrusion force was applied distal to the lateral incisors, the degree of labial tilting and the amounts of displacement of the six anterior teeth were the lowest, and the maximum von Mises stress was distributed evenly across all the teeth, regardless of the bone loss. Conclusions: Initial tooth displacement similar to pure intrusion of the six maxillary anterior teeth was induced when miniscrews were inserted distal to the maxillary canines and an intrusion force was applied distal to the lateral incisors. In this condition, the maximum von Mises stresses were relatively evenly distributed across all the teeth, regardless of the bone loss.

• Maxillofacial Plastic and Reconstructive Surgery
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• 제40권
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• pp.20.1-20.10
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• 2018

Background: In the absence of clear guidelines for facial aesthetic surgery, most surgeons rely on expert intuitive judgement when planning aesthetic and reconstructive surgery. One of the most famous theories regarding "ideal" facial proportions is that of the golden proportion. However, there are conflicting opinions as to whether it can be used to assess facial attractiveness. The aim of this investigation was to assess facial ratios of professional black models and to compare the ratios with the golden proportion. Methods: Forty photographs of male and female professional black models were collected. Observers were asked to assign a score from 1 to 10 (1 = not very attractive, 10 = very attractive). A total of 287 responses were analysed for grading behaviour according to various demographic factors by two groups of observers. The best graded photographs were compared with the least well-graded photographs to identify any differences in their facial ratios. The models' facial ratios were calculated and compared with the golden proportion. Results: Differences in grading behaviour were observed amongst the two assessment groups. Only one out of the 12 facial ratios was not significantly different from the golden proportion. Conclusions: Only one facial ratio was observed to be similar to the golden proportion in professional model facial photographs. No correlation was found between facial ratios in professional black models with the golden proportion. It is proposed that an individualistic treatment for each ratio is a rather better method to guide future practice.

• Archives of Plastic Surgery
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• 제48권6호
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• pp.660-669
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• 2021

Background The demand for aesthetic procedures continues to grow globally, particularly in East Asian countries. The popularity of specific aesthetic procedures varies, however, depending on the particular East Asian geographical region being studied. This study aimed to evaluate the experiences of and attitudes toward aesthetic procedures in five East Asian countries/regions, including China, Japan, South Korea, Hong Kong, and Taiwan. Methods To recruit participants, an online questionnaire was designed and distributed on social media networks between May 2015 and March 2016. The statistical analysis was conducted using SPSS software, version 22.0. Results A total of 3,088 people responded (approximately 600 in each country/region). Of these, 940 participants (47.8%) responded that they had experienced at least one aesthetic procedure in the past. Taiwan had the highest number of participants who had experienced at least one procedure (264/940, 41%), with primarily non-surgical experiences. Only in South Korea did surgical cosmetic experiences exceed non-surgical cosmetic experiences (55.9% vs. 44.1%). The popularity of particular procedures and the motivation for undergoing aesthetic procedures varied by country. Conclusions The popularity of aesthetic procedures continues to evolve. Similar trends were observed across the East Asian regions; however, each country had its unique demands and preferences. The information provided by this study can help aesthetic plastic surgeons further understand the patients in their corresponding region, customize their practice, and develop the requisite skills.

• Journal of Radiation Protection and Research
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• 제44권1호
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• pp.43-52
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• 2019

Background: The mid-term performance of clinical linear accelerator (LINAC) during volumetric modulated arc therapy (VMAT) treatment period is not performed in clinical practice and usually replaced with one-time plan quality assurance (QA). In this research we aim to monitor daily reproducibility of VMAT delivery from tracking individual leaf movement error and dosimetric error to evaluate the mid-term quality of the machine used. Materials and Methods: First, multileaf collimator (MLC) information was imported into MATLAB program to determine which of the MLC leaves in the leaf bank had the maximum RMS position error (maxRMS). We estimated where the maximum positional errors (maxPE) of the chosen leaf occur along its path length and tracked its daily variations over the entire treatment period. Secondly, picture information of dosimetric error from portal dosimetry was imported into MATLAB where representative high gamma index region (HGR) was determined as HGR with length of > 1 cm and their centers were daily tracked. Results and Discussion: The maxPEs in the brain and tongue cases were distributed broader than in other cases, but all data were found located within ${\pm}0.5mm$. From first day to last day all of five cases show the similar visual pattern of HGRs and Centers of the longest HGRs remained within ${\pm}1mm$ of that in first day. These findings prove excellent mid-term performance of the LINAC used in VMAT treatments over a full course of treatment. Conclusion: Tracking the daily location changes of leaf movement and dosimetric error can be a good indicator of predicting the daily quality like stability and reproducibility of beam delivering in VMAT treatment.