• 대한치과의사협회지
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• 제52권10호
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• pp.596-601
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• 2014

Computer-aided surgery is popular and useful in the field of oral and maxillofacial surgery, because of the possibility of simulation with a high accuracy. In all aspects of surgery, proper planning facilitates more predictable operative results, however before the use of virtual planning, much of this relied on 2-dimensional (2-D) imaging for treatment planning on a 3-dimensional (3-D) object and surgical trial and error. With real-time instrument positioning and clear anatomic identification, a computer-assisted navigation system (CANS) is exceptionally helpful in maxillofacial surgery. These techniques enable performing precise bony ablation and reconstruction, and also decrease surgical time and donor site defect.

• Maxillofacial Plastic and Reconstructive Surgery
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• 제37권
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• pp.44.1-44.6
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• 2015

Background: The present study introduces the design and fabrication of a simple surgical guide with which to perform genioplasty. Methods: A three-dimensional reconstruction of the patient's cranio-maxilla region was built, with a dentofacial skeletal model, then derived from CT DICOM data. A surgical simulation was performed on the maxilla and mandible, using three-dimensional cephalometry. We then simulated a full genioplasty, in silico, using the three-dimensional (3D) model of the mandible, according to the final surgical treatment plan. The simulation allowed us to design a surgical guide for genioplasty, which was then computer-rendered and 3D-printed. The manufactured surgical device was ultimately used in an actual genioplasty to guide the osteotomy and to move the cut bone segment to the intended location. Results: We successfully performed the osteotomy, as planned during a genioplasty, using the computer-aided design and computer-aided manufacturing (CAD/CAM) surgical guide that we initially designed and tested using simulated surgery. Conclusions: The surgical guide that we developed proved to be a simple and practical tool with which to assist the surgeon in accurately cutting and removing bone segments, during a genioplasty surgery, as preoperatively planned during 3D surgical simulations.

• 대한안전경영과학회:학술대회논문집
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• 대한안전경영과학회 1999년도 추계학술대회
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• pp.565-574
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• 1999

In reverse engineering area, it is rapidly developing reconstruction of surfaces from scanning or digitizing data, but geometric models of existing objects unavailable many industries. This paper describes new methodology of reverse engineering area, good strategies and important algorithms in reverse engineering area. Furthermore, proposing reconstruction of surface technique is presented. A method find base geometry and blending surface between them. Each based geometry is divided by triangular patch which are compared their normal vector for face grouping. Each group is categorized analytical surface such as a part of the cylinder, the sphere, the cone, and the plane that mean each based geometry surface. And then, each based geometry surface is implemented infinitive surface. Infinitive average surface's intersections are trimmed boundary representation model reconstruction. This method has several benefits such as the time efficiency and automatic functional modeling system in reverse engineering. Especially, it can be applied 3D scanner and 3D copier.

• Archives of Plastic Surgery
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• 제39권4호
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• pp.309-316
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• 2012

Computer aided design and manufacturing (CAD/CAM) technology today is the standard in manufacturing industry. The application of the CAD/CAM technology, together with the emerging 3D medical images based virtual surgical planning (VSP) technology, to craniomaxillofacial reconstruction has been gaining increasing attention to reconstructive surgeons. This article illustrates the components, system and clinical management of the VSP and CAD/CAM technology including: data acquisition, virtual surgical and treatment planning, individual implant design and fabrication, and outcome assessment. It focuses primarily on the technical aspects of the VSP and CAD/CAM system to improve the predictability of the planning and outcome.

• 한국방송∙미디어공학회:학술대회논문집
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• 한국방송공학회 1999년도 KOBA 방송기술 워크샵 KOBA Broadcasting Technology Workshop
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• pp.103.2-110
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• 1999

Facial model reconstruction and surgical simulation are essential parts in the computer-aided surgical system. Plastic surgeons use it to design appropriate repair plans and procedures before actual surgery is operated. In this work, the exploration of 3-D metamorphosis to them presents new results in these two parts.

• Maxillofacial Plastic and Reconstructive Surgery
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• 제41권
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• pp.41.1-41.6
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• 2019

Backgrounds: The purpose of this study is to discuss the total joint reconstruction surgery for a patient with recurrent ankylosis in bilateral temporomandibular joints (TMJs) using three-dimensional (3D) virtual surgical planning, computer-aided manufacturing (CAD/CAM)-fabricated surgical guides, and stock TMJ prostheses. Case presentation: A 66-year-old female patient, who had a history of multiple TMJ surgeries, complained of severe difficulty in eating and trismus. The 3D virtual surgery was performed with a virtual surgery software (FACEGIDE, MegaGen implant, Daegu, South Korea). After confirmation of the location of the upper margin for resection of the root of the zygoma and the lower margin for resection of the ankylosed condyle, and the position of the fossa and condyle components of stock TMJ prosthesis (Biomet, Jacksonville, FL, USA), the surgical guides were fabricated with CAD/CAM technology. Under general anesthesia, osteotomy and placement of the stock TMJ prosthesis (Biomet) were carried out according to the surgical planning. At 2 months after the operation, the patient was able to open her mouth up to 30 mm without complication. Conclusion: For a patient who has recurrent ankylosis in bilateral TMJs, total joint reconstruction surgery using 3D virtual surgical planning, CAD/CAM-fabricated surgical guides, and stock TMJ prostheses may be an effective surgical treatment option.

• 한국CDE학회논문집
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• 제15권4호
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• pp.297-305
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• 2010

Medical image acquisition techniques such as CT and MRI have disadvantages in that the numerous time and efforts are needed. Furthermore, a great amount of radiation exposure is an inherent proberty of the CT imaging technique, a number of side-effects are expected from such method. To improve such conventional methods, a number of novel methods that can obtain 3D medical images from a few X-ray images, such as algebraic reconstruction technique (ART), have been developed. Such methods deform a generic model of the internal body part and fit them into the X-ray images to obtain the 3D model; the initial shape, therefore, affects the entire fitting process in a great deal. From this fact, we propose a novel method that can generate a 3D vertebraic generic model based on the statistical database of CT scans in this study. Moreover, we also discuss a method to generate patient-tailored generic model using the facts obtained from the statistical analysis. To do so, the mesh topologies of CT-scanned 3D vertebra models are modified to be identical to each other, and the database is constructed based on them. Furthermore, from the results of a statistical analysis on the database, the tendency of shape distribution is characterized, and the modeling parameters are extracted. By using these modeling parameters for generating the patient-tailored generic model, the computational speed and accuracy of ART can greatly be improved. Furthermore, although this study only includes an application to the C1 (Atlas) vertebra, the entire framework of our method can be applied to other body parts generally. Therefore, it is expected that the proposed method can benefit the various medical imaging applications.

• 산업경영시스템학회지
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• 제41권4호
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• pp.123-130
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• 2018

Triangulation is one of the fundamental problems in computational geometry and computer graphics community, and it has huge application areas such as 3D printing, computer-aided engineering, surface reconstruction, surface visualization, and so on. The Delaunay refinement algorithm is a well-known method to generate quality triangular meshes when point cloud and/or constrained edges are given in two- or three-dimensional space. In this paper, we propose a simple but efficient algorithm to triangulate Voronoi surfaces of Voronoi diagram of spheres in 3-dimensional Euclidean space. The proposed algorithm is based on the Ruppert's Delaunay refinement algorithm, and we modified the algorithm to be applied to the triangulation of Voronoi surfaces in two ways. First, a new method to deciding the location of a newly added vertex on the surface in 3-dimensional space is proposed. Second, a new efficient but effective way of estimating approximation error between Voronoi surface and triangulation. Because the proposed algorithm generates a triangular mesh for Voronoi surfaces with guaranteed quality, users can control the level of quality of the resulting triangulation that their application problems require. We have implemented and tested the proposed algorithm for random non-intersecting spheres, and the experimental result shows the proposed algorithm produces quality triangulations on Voronoi surfaces satisfying the quality criterion.

• Journal of Korean Neurosurgical Society
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• 제52권6호
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• pp.541-546
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• 2012

Objective : The prefabrication of customized cranioplastic implants has been introduced to overcome the difficulties of intra-operative implant molding. The authors present a new technique, which consists of the prefabrication of implant molds using three-dimensional (3D) printers and polymethyl-methacrylate (PMMA) casting. Methods : A total of 16 patients with large skull defects (>100 $cm^2$) underwent cranioplasty between November 2009 and April 2011. For unilateral cranial defects, 3D images of the skull were obtained from preoperative axial 1-mm spiral computed tomography (CT) scans. The image of the implant was generated by a digital subtraction mirror-imaging process using the normal side of the cranium as a model. For bilateral cranial defects, precraniectomy routine spiral CT scan data were merged with postcraniectomy 3D CT images following a smoothing process. Prefabrication of the mold was performed by the 3D printer. Intraoperatively, the PMMA implant was created with the prefabricated mold, and fit into the cranial defect. Results : The median operation time was $184.36{\pm}26.07$ minutes. Postoperative CT scans showed excellent restoration of the symmetrical contours and curvature of the cranium in all cases. The median follow-up period was 23 months (range, 14-28 months). Postoperative infection was developed in one case (6.2%) who had an open wound defect previously. Conclusion : Customized cranioplasty PMMA implants using 3D printer may be a useful technique for the reconstruction of various cranial defects.

• 한국멀티미디어학회논문지
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• 제11권11호
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• pp.1592-1600
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• 2008

본 연구는 '캐릭터 구성 이미지 요소들의 재구성'이라는 논제를 바탕으로 하여 창의적 아이디어 발상을 돕기 위한 연구로 형태 이미지 요소들의 조합을 컴퓨팅 형태 생성에 의한 독창적이고 다양한 이미지 생성을 목적으로 하였다. 기존의 아이디어 발상법에서 벗어나 창의적 형태발상능력을 극대화시키고 사고의 한계를 극복하기 위한 디자인 발상법을 제시하기 위하여 창의적 아이디어 발상법에 대한 선행연구 중 비례를 이용한 기존 시스템인 PDS(Proportion Distort System) 아이디어 발상법의 문제점을 파악하여 보완한 창의적 아이디어 발상법인 CGS(Character Generation System)를 제시하였다. 본 연구는 영상 3D 캐릭터 디자인 개발프로세스 중 아이디어발상 또는 창조적인 이미지발상지원에 대한 한 방법으로 그 효과가 있을 것이며, 다양한 아이디어를 만들어 낼 수 있어 형태발상의 한계점을 극복할 수 있는 보조역할을 할 수 있을 것이라 기대된다.