• Imaging Science in Dentistry
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• 제42권1호
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• pp.25-33
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• 2012

Purpose : This study was performed to determine the accuracy of linear measurements on three-dimensional (3D) images using multi-detector computed tomography (MDCT) and cone-beam computed tomography (CBCT). Materials and Methods : MDCT and CBCT were performed using 24 dry skulls. Twenty-one measurements were taken on the dry skulls using digital caliper. Both types of CT data were imported into OnDemand software and identification of landmarks on the 3D surface rendering images and calculation of linear measurements were performed. Reproducibility of the measurements was assessed using repeated measures ANOVA and ICC, and the measurements were statistically compared using a Student t-test. Results : All assessments under the direct measurement and image-based measurements on the 3D CT surface rendering images using MDCT and CBCT showed no statistically difference under the ICC examination. The measurements showed no differences between the direct measurements of dry skull and the image-based measurements on the 3D CT surface rendering images (P>.05). Conclusion : Three-dimensional reconstructed surface rendering images using MDCT and CBCT would be appropriate for 3D measurements.

• 대한한의학회지
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• 제31권3호
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• pp.8-16
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• 2010

Objective: This study aimed to investigate the antitumor effects of water extracts of Panax notoginseng (WEPN) in NCI-H460 human lung cancer cell xenografted nude mice. Materials and Methods: We cultured NCI-H460 cell lines and xenografted them to nude mice. The mice were divided into 3 groups; positive control group, NCI-H460+150 mg/kg WEPN-treated group, and NCI-H460+300 mg/kg WEPN-treated group. They had been raised and treated in 28 days. We checked their body weight and tumor weight and volumes twice a week and their absolute organ weight and microhistological observation at the final day. We also calculated their tumor inhibition rate (I.R.), mean survival time and percent increase in life span (% ILS). Results: Body weight of WEPN (300 mg/kg) treated mice tended to slightly greater increase than those of the positive control group, but had no significance. Tumor volume (measurement with a caliper) of WEPN-treated mice tended to be lower than that of the positive control group. Inhibition rate (I.R.) of the WEPN group decreased more than the positive control group, but had no significance. Results of tumor weights and volume (plethysmography) had no significance. Mean survival time and percent increase in life span (% ILS) in the WEPN 300 mg/kg treatment group were higher than those of any other group (p<0.05). In absolute organ weights, the WEPN (150-300 mg/kg) treatment group decreased liver weights (p<0.05). Liver tissue of mice treated with WEPN (300 mg/kg) did not show any specific lesions. Conclusion: We suggest that WEPN may have potential as a growth inhibitor of solid tumors induced by NCI-H460 without any side effects. However, this study has limitations in proving anti-tumor effects of WEPN, so further studies to overcome those limitations will be needed.

• Imaging Science in Dentistry
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• 제42권4호
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• pp.243-247
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• 2012

Purpose: This study was performed to compare the inverted digital images and film-based images of dry pig mandibles to measure the periodontal bone defect depth. Materials and Methods: Forty 2-wall bone defects were made in the proximal region of the premolar in the dry pig mandibles. The digital and conventional radiographs were taken using a Schick sensor and Kodak F-speed intraoral film. Image manipulation (inversion) was performed using Adobe Photoshop 7.0 software. Four trained examiners made all of the radiographic measurements in millimeters a total of three times from the cementoenamel junction to the most apical extension of the bone loss with both types of images: inverted digital and film. The measurements were also made in dry mandibles using a periodontal probe and digital caliper. The Student's t-test was used to compare the depth measurements obtained from the two types of images and direct visual measurement in the dry mandibles. A significance level of 0.05 for a 95% confidence interval was used for each comparison. Results: There was a significant difference between depth measurements in the inverted digital images and direct visual measurements (p>|t|=0.0039), with means of 6.29 mm ($IC_{95%}$:6.04-6.54) and 6.79 mm ($IC_{95%}$:6.45-7.11), respectively. There was a non-significant difference between the film-based radiographs and direct visual measurements (p>|t|=0.4950), with means of 6.64mm($IC_{95%}$:6.40-6.89) and 6.79mm($IC_{95%}$:6.45-7.11), respectively. Conclusion: The periodontal bone defect measurements in the inverted digital images were inferior to film-based radiographs, underestimating the amount of bone loss.

• 대한치과기공학회지
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• 제42권1호
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• pp.17-25
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• 2020

Purpose: The purpose of this study was to evaluate and compare the accuracy of definitive casts that are fabricated from digital intraoral impression and conventional impression technique. Methods: A master model(ANNA-4, Frasaco GmbH, Tettnang, Germany) with the prepared upper full arch tooth was used. Conventional impression and then stone model(n=10) were produced from this master model, and on the other hands, digital impressions were made with the CS-3600 intraoral scanner(n=10). Six linear measurements were recorded between landmarks, directly on each of the stone models on two occasions by a single examiner. Measurements were made with a digital caliper to the nearest 0.01mm from manual models and with the software(Delcam PowerSHAPE) from the virtual models. The t-student test for paired samples and intraclass correlation coefficient(ICC) were used for statistical analysis. Results: The measurement of two methods showed good reliability. The ICC of the two models were 0.88~0.91(stone model) and 0.94~0.99(digital model). The mean differences to master model for stone model and digital model were 0.10~0.14mm, and 0.14~0.20mm, respectively. Conclusion: The definitive casts obtained with digital intraoral technique model had significantly larger dimensions as compared to those of the stone model. However, the differences to the master model detected appear to provide enough accuracy and reliability for clinical application.

• 대한치과보철학회지
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• 제36권3호
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• pp.468-482
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• 1998

Since the concept of osseointegration was introduced by Branemark of Sweden, dental implants have been used for various dental prosthetic treatments. The survival rate of dental implant is likely to be closely related to the total biomechanical role of each component of implant system. The use of interchangeable component is very attractive for dental practitioners because such an approach would save treatment cost, flexibility of prosthetic treatment options as well as conveniences. Therefore, the use of interchangeable implant system has been increasing without scientific assessment of safety and efficacy of various interchangeable implant system. The purpose of this study, therefore, were to compare the geometric characteristic of four interchangeable dental implant screws and the loosening torque of these screws. Four types of dental implant screws tested in this study were Nobelpharma, 3i, Impla-med, Restore. Four screws each of the test specimens were subjected for scanning electron microscopic examinations under the same condition and a 35x magnified standard SEM picture was objected from each test specimen using JSM-5200 scanning microscope. From each of the SEM pictures, eight parameters. i.e., diameter of screw head. screw length, thread pitch, major diameter. neck diameter, neck length, crest width and root width were determined using a caliper. The measurement for each parameters were then corrected for their magnification factor. The loosening torque were also determined by using a torque gauge. All of the measurements were statistically analyzed by ANOVA test and multiple range test. Statistical significance was set in advance at the probability level of less than 0.05. All analyses were done with SPSS software for the personal computer. The conclusion obtained from this studies were summarized as the following; 1. No statistically significances were noted in the thread pitch. and crest width in the four screws, and in the case of major diameter, the Impla-med screw was significantly smaller than the other three screws (p<0.05). Therefore, four implant bolts could be physically inserted in a abutment nuts. 2. The diameter of screw head was decreased in the order of Restore, 3i, Nobelpharma, Impla-med screws and the length of screws were decreased in the order of 3i, Restore, Nobelpharma and Impla-med. The diameter of neck was decreased in the order of Impla-med, Restore. Nobelpharma, 3i screws. The differences of each of these parameters were statistically significant (p<0.05). The width of root of screws were decreased in the order of Nobelpharma, Impla-med, Restore and 3i. The differences among Nobelpharma and Impla-med. Restore and 3i were statistically significant (p<0.05). 3. When the screws were loosening 1, 3, 4 and 5 times, the loosening torque for Impla-med and 3i screws were significantly higher than that of Nobelpharma or Restore screws (p<0.05). However, when statistically smaller than that of 3i, Restore or Nobelpharma screws(p<0.05).

• 한국의학물리학회:학술대회논문집
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• 한국의학물리학회 2002년도 Proceedings
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• pp.457-460
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• 2002

The image quality of three-dimensional (3D) images has been widely investigated by the qualitative analysis method. A need remains for an objective and quantitative method to assess the image quality of 3D volume-rendered images. The purpose of this study was to evaluate the quantitative accuracy of distance measurements on 3D volume-rendered images of a dry human skull by using multi-detector computed tomography (MDCT). A radiologist measured five times the twenty-one direct measurement line items composed among twelve reference points on the skull surface with a digital vernier caliper. The water filled skull specimen was scanned with a MDCT according to the section thicknesses of 1.25, 2.50, 3.75, and 5.00 mm for helical (high quality; pitch 3:1) scan mode. MDCT data were reconstructed with its acquisition section thickness and with 1.25 mm section thickness for all scans. An observer also measured seven times the corresponding items on 3D volume-rendered images with measuring tools provided by volumetric analysis software. The quantitative accuracy of distance measurements on the 3D volume-rendered images was statistically evaluated (p-value < 0.05) by comparatively analyzing these measurements with the direct distance measurements. The accuracy of distance measurements on the 3D volume-rendered MDCT images acquired with 1.25, 2.50, 3,75 and 5.00 mm section thickness and reconstructed with its section thickness were 48%, 33%, 23%, and 14%, respectively. Meanwhile, there were insignificant statistical differences in accuracy of distance measurements among 3D volume-rendered images reconstructed with 1.25 mm section thickness for the each acquisition section thickness. MDCT images acquired with thick section thickness and reconstructed with thin section thickness in helical scan mode should be effectively used in medical planning of 3D volume-rendered images. The quantitative analysis of distance measurement may be a useful tool for evaluating the quantitative accuracy and the defining optimal parameters of 3D volume-rendered CT images.

• Imaging Science in Dentistry
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• 제44권4호
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• pp.257-262
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• 2014

Purpose: This study was performed to evaluate the effect of changing the orientation of a reconstructed image on the accuracy of linear measurements using cone-beam computed tomography (CBCT). Materials and Methods: Forty-two titanium pins were inserted in seven dry sheep mandibles. The length of these pins was measured using a digital caliper with readability of 0.01 mm. Mandibles were radiographed using a CBCT device. When the CBCT images were reconstructed, the orientation of slices was adjusted to parallel (i.e., $0^{\circ}$), $+10^{\circ}$, $+12^{\circ}$, $-12^{\circ}$, and $-10^{\circ}$ with respect to the occlusal plane. The length of the pins was measured by three radiologists, and the accuracy of these measurements was reported using descriptive statistics and one-way analysis of variance (ANOVA); p<0.05 was considered statistically significant. Results: The differences in radiographic measurements ranged from -0.64 to +0.06 at the orientation of $-12^{\circ}$, -0.66 to -0.11 at $-10^{\circ}$, -0.51 to +0.19 at $0^{\circ}$, -0.64 to +0.08 at $+10^{\circ}$, and -0.64 to +0.1 at $+12^{\circ}$. The mean absolute values of the errors were greater at negative orientations than at the parallel position or at positive orientations. The observers underestimated most of the variables by 0.5-0.1 mm (83.6%). In the second set of observations, the reproducibility at all orientations was greater than 0.9. Conclusion: Changing the slice orientation in the range of $-12^{\circ}$ to $+12^{\circ}$ reduced the accuracy of linear measurements obtained using CBCT. However, the error value was smaller than 0.5 mm and was, therefore, clinically acceptable.

• 한국식품영양과학회지
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• 제26권2호
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• pp.291-299
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• 1997

에너지 섭취량은 남학생이 권장량의 89.7%, 여학생이 100% 섭취하고 있었다. 남학생의 열량 섭취량이 권장량 및 활동량에 비해 많은 양이 부족하게 섭취되고 있었다. 반면, 여학생은 섭취열량, 권장량, 활동량 간의 균형이 잘 이뤄지고 있는 것으로 조사되었다. 권장량에 비해 남학생은 총열량, 칼슘, 철의 섭취량이 약간 부족하였고, 여학생은 철의 섭취량이 미달되는 것으로 나타나 이 부분에 대한 영양교육이 이루어져야 할 것이다. 그러나 전반적으로 영양소의 섭취상태는 양호한 것으로 나타났다. 탄수화물과 단백질, 지방의 열량에 대한 구성비는 남학생이 64 : 16 : 20, 여학생이 62 : 16 : 22로 나타나 이상적인 섭취비율과 비슷한 비율을 보였다. 조사대상자의 평균 신장은 남학생이 160.0cm, 여학생이 155.5cm였고, 평균 체중은 남학생이 49.4kg, 여학생이 48.9kg으로 구미지역 중학생들의 발육상태가 양호한 것으로 나타났다. 상완위 둘레는 남학생이 23.1cm 여학생이 22.6cm로 평균적인 발육상태를 보였다. Caliper로 측정한 상박부 전 후면, 좌측 견갑골, 장골절, 종아리 부위의 피하지방 두께는 남학생이 7.3mm, 13.9mm, 11.4mm, 15.4mm, 21.2mm 여학생이 11.2mm, 18.4mm, 16.7mm, 18.4mm, 21.6mm로 나타났다. 비만으로 판정된 학생은 RBW는 남학생 5%, 여학생 6%, BMI는 남학생 4%, 여학생 10%였고, RI는 남학생 7%, 여학생 13%로 나타났으며, OI는 남학생 4%, 여학생 9%로 나타나 체격지수에 의한 비만판정에는 여학생이 남학생 보다 높은 비만율을 보였다. 상박부후면의 피부두겹 두께에 의한 비만판정은 남학생이 16mm, 여학생이 20mm 이상으로 이에 해당하는 남학생은 43명(24%), 여학생은 66(34%)명으로 나타나 체격지수에 의한 비만 보다 훨씬 높게 평가되는 경향을 보였다. Slaughter의 방법으로 비만으로 판정된 학생은 남학생이 105명(59%), 여학생이 58명(30%)으로 판정되었다. BMI를 이용한 Deurenberg의 방법에 의한 비만학생은 남학생이 27명(15%) 여학생이 13명(7%)으로 판정되었다. Siri의 방법에 의한 비만학생은 남학생 24명(14%), 여학생 2명(1%)으로 판정되었다. 체격지수와 부위별 피지후와의 상관관계에서 RBW는 네부위의 합과 가장 높은 관련 (.6776)을 보였고, BMI(.7542), RI(.7669), OI(.7675), %fatII(.8007)는 모두 견갑골과 가장 높은 상관관계를 보였다.

• 해양환경안전학회지
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• 제26권2호
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• pp.219-226
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• 2020

선체구조의 품질검사 중 가장 일반적인 방법의 하나는 비파괴검사이다. 하지만 복합소재 선체는 강화재와 수지로 구성된 여러가지 재료가 섞여 있고 또 생산환경과 작업자에 따라 FRP(Fiber-Reinforced Plastics) 제작품질에 차이가 발생할 가능성이 크기 때문에 정확한 검사평가는 쉽지 않은 일이다. 특히 FRP 선박의 경우에는 다른 구조물보다 두께가 매우 두껍고 주로 수척층 공법을 이용하기 때문에 더욱 그렇다. 초음파 탐상의 조건 중 검사체의 밀도가 매우 중요하기 때문에 본 연구에서는 FRP 선박 제작에 널리 사용되고 있는 소재와 유리섬유강화재 중량 비율로 제작된 선박의 외판을 검사체로 선정하고, Pulse-Echo 초음파 탐상기를 활용하여 GFRP(Glass Fiber-Reinforced Plastics) 선체 외판의 초음파 탐상을 위한 적정 조건을 조사하였다. 1.00 MHz, 2.25 MHz, 5.00 MHz 세 종류 탐촉자로 A-Scan을 실시하였으며 선체 외판의 두께 검사결과와 비교분석함으로써 적정 초음파 탐상 조건을 찾고자 하였다. 연구결과 탐촉자의 초음파 주파수가 높아질수록 수신자의 반사파 음향 속력을 감소시켜야 더 정도 높은 두께 측정 결과를 얻을 수 있었으며, 상대적으로 낮은 초음파 주파수 탐촉자에서 더 적은 오차가 발생함을 확인할 수 있었다.

• 대한소아치과학회지
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• 제47권1호
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• pp.17-24
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• 2020

이 연구의 목적은 소아 얼굴 연조직의 선형 길이를 비교하여 삼차원 입체영상의 정확성과 재현성을 평가하는 것이다. 연구는 7 - 12세 아동 15명을 대상으로 하였다. 환자의 안모에 23개의 계측 점을 표시하고, 전자 캘리퍼를 이용하여 16 개의 선형길이를 직접 2번 계측하였다. 3차원(3D) 스캐너를 이용하여 2개의3D 얼굴 영상을 만들었으며, 직접계측과 동일한 16개의 선형 길이를 계측하였다. 연구결과 정확성 평가에서 전체 평균 차이 값은 0.9 mm였다. 3D 영상의 재현성은 직접계측의 재현성과 거의 유사한 정도로 나타났다. 이에 따라 이 3D 영상장비는 소아에서 임상적으로 충분한 정확성과 재현성을 가지고 있었다. 3D 영상 시스템은 정확한 이미지를 위하여 대상의 협조가 필요하다. 소아의 정확한 3D영상을 얻기 위한 구체적인 지시사항을 바탕으로 촬영을 한다면, 이 3D 영상 장비는 향후 소아의 성장과 발달을 조사하고, 소아교정치료에서 결과를 평가하는데 유용하게 사용될 수 있을 것이다.