• Radiation Oncology Journal
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• 제16권1호
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• pp.71-79
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• 1998

목적 : 비 상업용 3차원 컴퓨터치료계획시스템인 Plunc의 구축 사례를 소개하고 이의 임상적용 가능성에 대하여 검증하고자 한다. 대상 및 방법 : 미국 North Carolina 대학에서 개발된 3차원 치료계획시스템인 Plunc의 소스코드를 제공받아, PC용 Unix인 Linux 환경의 Pentium Pro 200MHz(128MB RAM, Millennium VGA)에서 설치하였다. 본과의 6MV 광자선(Siemens MXE 6740)에 대한 출력인자, 최대산란비, 최대산란인자, 쐐기의 모양 및 감쇄인자 등의 빔데이터를 입력한 후, 일반적인 치료조건인 loom 깊이의 회전중심점에서의 심부선량백분율, 선량측면도, oblique 입사빔 및 공기간격 하에서의 선량계산 결과를 물팬톰에서의 측정치와 비교, 분석하였다. 결과 : Plunc는 원래 CT 영상데이터를 이용한 모의치료기로써 개발되어, 빔 설계가 매우 편리하도록 사용자 인터페이스가 구성되어 있으며, BEV, DRR 및 영상합성 등의 기능을 갖추고 있다. 선량계산은 10초 정도가 소요되는 3차원 선량분포나 선량체적히스토그람을 제외하고는 거의 실시간으로 실행되었다. Plunc에 의한 선량 계산 값을 측정값과 비교한 결과, 심부선량백분율의 경우, 선량증가영역을 제외하고는 $1\%$이내에서 일치하였다. 또한, 선량측면도의 경우, $5\%$가량의 선량감소를 나타내는 치료영역 크기 밖의 저선량 영역을 제외하고는 $2\%$ 이내에서 일치하였다. Oblique 입사 빔의 경우, 빔 중심축을 포함하는 평면상의 선량분포가 선량이 $30\%$ 이하인 영역을 제외하고는 비교적 잘 일치하였다. 공기간격을 통과한 빔에 대한 선량측면도의 비교 결과, 중심 축에서의 선량 값에 대해 $5\%$의 오차를 보였다. 결론 : Plunc의 광자선량계산의 정밀도는 일반적인 치료조건하에서 약 $2-5\%$ 내외의 오차로써, 측정치에 대한 보정에 근거한 알고리즘을 사용하는 일반 치료계획시스템과 비슷한 수준이라 사료된다. 현재로서는 전자선에 대한 선량계산이 불가능하기 때문에 완전한 형태의 치료계획시스템이 되기 위해서는 향후, 전자선에 대한 계산모듈의 개발과 광자선 선량계산 또한 보다 정밀한 선량계산이 가능한 컨벌루션 방법과 같은 3차원 선량계산모듈의 개발도 필요하다. Plunc는 상업용 3차원 치료계획 시스템의 사용이 현실적으로 어려운 여건의 병원에서 2차원 치료계획시스템과 상호 보완적으로 사용한다면 2차원 치료계획시스템이 갖는 많은 제약을 극복할 수 있을 것으로 사료된다.

• 한국방재학회:학술대회논문집
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• 한국방재학회 2007년도 정기총회 및 학술발표대회
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• pp.418-421
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• 2007

Application이나 3D 모델로 구현된 맵 관련 위성영상, UAV 영상을 통해 현장감 있는 정보를 정확하게 얻는 것은 중요하다. 방재관련 업계에서는 3D 모델링에 근거한 재해지역 주변의 정확한 3차원 지형공간정보 취득의 필요성을 인식하고 있다. 본 논문에서는 GIS 기술을 활용하여 3D 모형을 생성하고, 각종 영상들을 로딩하고 처리하는 부분에 있어서의 방법을 제시하였다. 그리고 대상지역의 수치고도모형과 지형지물을 위해 수치 지형도를 사용하였다. 결과는 3D 모델링 기반의 간단한 application의 구현이다. 제시한 방법은 방재 관련업계의 종사자들에게 더 나은 방법을 제시하기에 활용 가능하다.

• 한국전자통신학회논문지
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• 제8권1호
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• pp.191-197
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• 2013

방사선과 의사들은 CT 및 MRI 스캐너로부터 얻어진 인체의 단면 영상을 연속적으로 보고 실제 3차원적으로 인체가 어떻게 구성되어 있는지를 상상하여 병변을 구별하는데, 의학영상을 이용한 인체 장기의 3차원 시각화는 2차원 형태의 인체 단면 영상들을 복잡한 알고리즘이나 고성능의 컴퓨팅 파워를 사용하여 실제 인체와 같이 3차원으로 재구성하여 보여준다. 단면 영상의 추적, 관심영역의 표시 및 추출등과 같은 2차원 영상분석은 시간이 많이 소모되고, 주관적일 수가 있으며, 수작업인 관계로 빈번한 에러가 발생하는 단점을 가지는데, 이와 같은 2차원 의료 영상 분석의 단점을 보완하기 위해 의학영상처리 기술과 접목한 3차원 의료 영상의 시각화는 필수적이라 할 수 있다. 명암값 임계치 방법, 영역확장(region growing) 방법, 윤곽선(contour) 추출 방법 및 변형모델(deformable model) 방법을 사용하여 인체의 각 장기를 분리하였으며, 텍스쳐분석(texture analysis)을 통하여 고안된 특징자를 이용하여 암 부분을 인식하는데 사용하였고, 원근투영(perspective projection) 및 볼륨 데이터의 표면을 렌더링하기 위해 마칭큐브(marching cube) 알고리즘을 사용하였다. 인체 및 분리된 장기에 대한 3차원 시각화는 방사선치료계획(radiation treatment planning), 외과 수술계획, 모의수술, 중재적(interventional)시술 및 영상유도수술(image guided surgery)에 효과적으로 사용될 수 있다.

• 한국신뢰성학회지:신뢰성응용연구
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• 제18권3호
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• pp.201-207
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• 2018

Purpose: To develop the reliability growth planning for a subsystem of guided weapon system using PM2-Continuous model. Methods: The target MTBF of the subsystem is set by allocating the system target MTBF to the lower level, where ARINC method is applied. Other model parameters such as initial MTBF, management strategy ratio and average fix effectiveness factor are chosen from historical growth parameter estimates. Given the values of model parameters, the reliability growth planning curve using PM2-Continuous model is constructed and the sensitivity analyses are performed for the changes of model parameters. Results: We have developed the reliability growth plan for a subsystem of guided weapon system using PM2-Continuous model. It was found that the smaller the ratio of initial MTBF to target MTBF, the smaller the management strategy ratio, the smaller the average fix effectiveness factor, and the shorter the development test period, the higher reliability growth is required. Conclusion: The result of this study will be used as a basis for establishing the reliability growth plan, the test period setting and the budget appropriation for the similar system entering the system development stage in the future.

• 의료ㆍ복지 건축 : 한국의료복지건축학회 논문집
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• 제13권2호
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• pp.27-36
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• 2007

Recently, hospital patients experience anxiety, confusion, and stress about wayfinding as the spacial layout and treatment circulatory system of hospitals have become complicated due to their oversized and complex structure. As part of finding a solution to the problem, this study seeks to examine what are the essential elements of the wayfinding planning of O.P.D. in general hospitals, to develop the model of wayfinding, and to suggest the methods of improving the wayfinding system. The research methods of this study adopted were literature review in wayfinding cognition, plan analysis of ten general hospitals, space analysis of these hospitals through space syntax, analysis of the system of visual-perceptual information through a field study, and analysis of surveys and follow-up surveys conducted to support the results. Based on these results, the proposals for finding decision points, providing the information, and developing a model planning are listed as follows. 1) The comprehensive understanding of O.P.D. spacial layout and the visual-perceptual information system is necessary to find the essential elements of wayfinding. 2) The decision points are found through the full understanding of spacial functions, circulation systems, and facility configuration, considering the spacial layout, the bound of the visual-perceptual information system, and the circulatory system. Furthermore, the information decision points could be confined by space syntax. 3) The checklist and color compound & color codes, developed through the planning of signage system and color system could be applied to the methods of providing the information. 4) The planning of wayfinding system according to the whole process of practices for outpatients was mentioned above. The system of visual-perceptual information developed through the process of this study should be integrated in the spacial layout of the whole O.P.D.

• 한국의학물리학회지:의학물리
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• 제28권1호
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• pp.27-32
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• 2017

We investigated the effect of a commercial iterative reconstruction technique (iDose, Philips) on the image quality and the dose calculation for the treatment plan. Using the electron density phantom, the 3D CT images with five different protocols (50, 100, 200, 350 and 400 mAs) were obtained. Additionally, the acquired data was reconstructed using the iDose with level 5. A lung phantom was used to acquire the 4D CT with the default protocol as a reference and the low dose (one third of the default protocol) 4D CT using the iDose for the spine and lung plans. When applying the iDose at the same mAs, the mean HU value was changed up to 85 HU. Although the 1 SD was increased with reducing the CT dose, it was decreased up to 4 HU due to the use of iDose. When using the low dose 4D CT with iDose, the dose change relative to the reference was less than 0.5% for the target and OARs in the spine plan. It was also less than 1.1% in the lung plan. Therefore, our results suggests that this dose reduction technique is applicable to the 4D CT image acquisition for the radiation treatment planning.

• 대한치과의사협회지
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• 제50권11호
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• pp.660-669
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• 2012

We describes the process of 3D virtual treatment planning and of CAD/CAM for surgical splint in orthognathic surgery. The potential benefits and disadvantages of 3D virtual approach and the use of CAD/CAM system for the treatment of the patient with a maxillofacial deformity are discussed. For the more convenient applications,3D software should be improved.

• 한국농공학회:학술대회논문집
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• 한국농공학회 2005년도 학술발표논문집
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• pp.272-277
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• 2005

Initial mixing characteristics in near field regions were analyzed by FLOW-3D, for analyzing mixing behavior of submerged discharge from freshwater lake in sea water. FLOW-3D model was applied to the region near Geum-ho dike for its verification. Simulation results from FLOW-3D were compared to the observed data for the verification periods. FLOW-3D showed resonable prediction results compared to the observed data, except underestimation in area near outfall. Particularly, FLOW-3D showed a good prediction for movement of buoyancy jets. In addition, FLOW-3D model was applied to the region near Saemangeum dike, which is to be constructed in near future. It was expected that the results of model application to Saemangeum area could provide substantial information in planning submerged discharge facilities. Based on the model applications to Saemangeum area, it was recommended that outfall should be located to the distance which gave an enough depth of outfall from water surface.

• Archives of Plastic Surgery
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• 제47권5호
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• pp.428-434
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• 2020

Background Three-dimensional (3D) model printing improves visualization of anatomical structures in space compared to two-dimensional (2D) data and creates an exact model of the surgical site that can be used for reference during surgery. There is limited evidence on the effects of using 3D models in microsurgical reconstruction on improving clinical outcomes. Methods A retrospective review of patients undergoing reconstructive breast microsurgery procedures from 2017 to 2019 who received computed tomography angiography (CTA) scans only or with 3D models for preoperative surgical planning were performed. Preoperative decision-making to undergo a deep inferior epigastric perforator (DIEP) versus muscle-sparing transverse rectus abdominis myocutaneous (MS-TRAM) flap, as well as whether the decision changed during flap harvest and postoperative complications were tracked based on the preoperative imaging used. In addition, we describe three example cases showing direct application of 3D mold as an accurate model to guide intraoperative dissection in complex microsurgical reconstruction. Results Fifty-eight abdominal-based breast free-flaps performed using conventional CTA were compared with a matched cohort of 58 breast free-flaps performed with 3D model print. There was no flap loss in either group. There was a significant reduction in flap harvest time with use of 3D model (CTA vs. 3D, 117.7±14.2 minutes vs. 109.8±11.6 minutes; P=0.001). In addition, there was no change in preoperative decision on type of flap harvested in all cases in 3D print group (0%), compared with 24.1% change in conventional CTA group. Conclusions Use of 3D print model improves accuracy of preoperative planning and reduces flap harvest time with similar postoperative complications in complex microsurgical reconstruction.

• 대한치과교정학회지
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• 제43권2호
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• pp.62-73
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• 2013

Objective: The purpose of this study was to assess new three-dimensional (3D) cephalometric variables, and to evaluate the relationships among skeletal and dentoalveolar variables through 3D cephalometric analysis. Methods: Cone-beam computed tomography (CBCT) scans were acquired from 38 young adults (18 men and 20 women; $22.6{\pm}3.2$ years) with normal occlusion. Thirty-five landmarks were digitized on the 3D-rendered views. Several measurements were obtained for selected landmarks. Correlations among different variables were calculated by means of Pearson's correlation coefficient values. Results: The body of the mandible had a longer curve length in men ($102.3{\pm}4.4$ mm) than in women ($94.5{\pm}4.7$ mm) (p < 0.001), but there was no significant difference in the maxillary basal curve length. Men had significantly larger facial dimensions, whereas women had a larger gonial angle ($117.0{\pm}4.0$ vs. $113.8{\pm}3.3$; p < 0.001). Strong-to-moderate correlation values were found among the vertical and transverse variables (r = 0.71 to 0.51). Conclusions: The normative values of new 3D cephalometric parameters, including the maxillary and mandibular curve length, were obtained. Strong-to-moderate correlation values were found among several vertical and transverse variables through 3D cephalometric analysis. This method of cephalometric analyses can be useful in diagnosis and treatment planning for patients with dentofacial deformities.