• 대한의용생체공학회:학술대회논문집
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• 대한의용생체공학회 1993년도 춘계학술대회
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• pp.57-60
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• 1993

A finite element-based computer simulation of excimer laser susery was conducted to study some factors on the surgery. In particular, the radius of curvature at the apex of the cornea was examined under various surgical conditions. Corneal tissue was assumed to be a nearly incompressible, linear elastic, homogeneous, isotropic material under very small deformation. The geometry of the human cornea was taken from the experimental data[1]. The simulation utilized ANSYS(Swanson Analysis System Inc.Rev.4.4A). In this study, the major factors which affect the outcomes of the excimer laser surgery were investigated. First, two patterns of surgery with various surgery thickness(40-70micrometers) were examind. The pattern#1 describes the meridian from the apex to the edge of the surgery area to be straight. And the corresponding meridian of the pattern 2 can be expressed as a quardratic function. The results show that the pattern #2 is more realistic and effective. Then, the effects of other factors were investigated based on the pattern #2. Other factors are:various diameters of the surgical area (3-8 milimeters), Young's modules(3.5-4.5MPa), and depth of surgery at the apex(40-70micrometers). Compared with the computer simulation of the radial keratotomy surgery[2], the excimer laser surgery was proven to be more effective in treating myopia patients. In conculusion, the results of the simulation are qualitative agreement with clinical experience[3] indicating the potential of the finite element model of the surgery as a guideline to the surgeon before actual surgery.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2005년도 춘계학술대회 논문집
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• pp.911-914
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• 2005

Soft tissue characterization and modeling based on living tissues has been investigated in order to provide a more realistic behavior in a virtual reality based surgical simulation. In this paper, we characterize the nonlinear viscoelastic properties of intra-abdominal organs using the data from in vivo animal experiments and inverse FE parameter estimation algorithm. In the assumptions of quasi-linear-viscoelastic theory, we estimated the nonlinear material parameters to provide a physically based simulation of tissue deformations. To calibrate the parameters to the experimental results, we developed a three dimensional FE model to simulate the forces at the indenter and an optimization program that updates new parameters and runs the simulation iteratively. The comparison between simulation and experimental behavior of pig intra abdominal soft tissue are presented to provide a validness of the tissue model using our approach.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 2002년도 가을 학술발표회 논문집
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• pp.62-69
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• 2002

With the development of CUP speed and graphic technology, real-time simulation of deformable object is embossed as an essential issue in engineering field. Recently, it has been applied to the surgical training and game animation with haptic force feedback. But real time simulation of deformable objects is not easy because of the conflicting demands of speed and low latency and physical accuracy. In this study, we present the implementation of boundary element method(BEM) which is combined with the nonuniform B-spline surface. It is working together with the real-time simulation technique and the geometry data is altered by handling control points without preprocessing routine.

• 대한한의진단학회지
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• 제13권2호
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• pp.140-148
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• 2009

The primary market of acupuncture treatment is concentrated on disorders of the musculoskeletal system. This study researches the clinical use of the musculoskeletal system evaluation with a computer simulation. Two fields are examined - patient evaluation and patient treatment. In the field of evaluation, the simulation is used to evaluates the prognosis of medical treatment. In the field of treatment, the simulation is used to decide the most suitable way to perform surgery using the quantitative evaluation about various cases of surgical results.

• Journal of International Society for Simulation Surgery
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• 제2권2호
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• pp.58-63
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• 2015

Image-guided neurosurgery (IGN) is a technique for localizing objects of surgical interest within the brain. In the past, its main use was placement of electrodes; however, the advent of computed tomography has led to a rebirth of IGN. Advances in computing techniques and neuroimaging tools allow improved surgical planning and intraoperative information. IGN influences many neurosurgical fields including neuro-oncology, functional disease, and radiosurgery. As development continues, several problems remain to be solved. This article provides a general overview of IGN with a brief discussion of future directions.

• Journal of International Society for Simulation Surgery
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• 제3권1호
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• pp.1-8
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• 2016

In the field of Radiology, the Computer Aided Diagnosis is the technology which gives valuable information for surgical purpose. For its importance, several computer vison methods are processed to obtain useful information of images acquired from the imaging devices such as X-ray, Magnetic Resonance Imaging (MRI) and Computed Tomography (CT). These methods, called pattern recognition, extract features from images and feed them to some machine learning algorithm to find out meaningful patterns. Then the learned machine is then used for exploring patterns from unseen images. The radiologist can therefore easily find the information used for surgical planning or diagnosis of a patient through the Computer Aided Diagnosis. In this paper, we present a review on three widely-used methods applied to Computer Aided Diagnosis. The first one is the image processing methods which enhance meaningful information such as edge and remove the noise. Based on the improved image quality, we explain the second method called segmentation which separates the image into a set of regions. The separated regions such as bone, tissue, organs are then delivered to machine learning algorithms to extract representative information. We expect that this paper gives readers basic knowledges of the Computer Aided Diagnosis and intuition about computer vision methods applied in this area.

• Journal of International Society for Simulation Surgery
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• 제1권1호
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• pp.16-18
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• 2014

The orbit has a very special anatomical structure. The complex anatomical structure should be restored when we encounter the patient with orbital wall fracture. Unless these specific anatomy were reconstructed well, the patient should suffer from various complications such enophthalmos, diplopia or orbital deformity. In addition, because the patient has a his own specific orbital shape, individualized approach will be necessary. The aim of this trial is to try to restore the original orbit anatomy as possible based on the mirrored three dimensional CT images based on the computer simulation. Preoperative computed tomography (CT) data were processed for the patient and a rapid prototyping (RP) model was produced. At the same time, the uninjured side was mirrored and superimposed onto the traumatized side, to create a mirror-image of the RP model. In order to restore the missing skipped images between the cuts of CT data because of the thinness of the orbital walls, we manipulated the DICOM data for imaging the original orbital contour using the preoperatively manufactured mirror-image of the RP model. And we fabricated Titanium-Medpor to reconstruct three-dimensional orbital structure intraoperatively. This prefabricated Titanium-Medpor was then inserted onto the defected orbital wall and fixed. Three dimensional approach based on the computer simulation turned out to be very successful in this patient. Individualized approach for each patient could be an ideal way to manage the traumatic patients in near future.

• Journal of International Society for Simulation Surgery
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• 제2권2호
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• pp.80-82
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• 2015

The mandibuloplasty for the facial aesthetic reason has been the one of the most popular procedures in aesthetic facial bone surgery in East Asia. Most East Asian women prefer smaller-looking and smooth-shaped facial contour. Prominent mandible angle which are common in Asia would be the main problem for smooth facial contour. In addition, recently, the mandibular body and broad chin shape also are known to be remodeled in order to get the ideal smooth facial shape. However, mandibuloplasty is not that easy to cut because many patients has inward mandibular angle and the visual field in operation is limited. The aim of this trial is to try to provide the prefabricated cutting guide for the symmetric and appropriate mandibuloplasty with the surgeons. Preoperative computed tomography(CT) data were processed for the patient and computer simulation model was produced. Then, mandibuloplasty was done on the computer simulation screen. Based on this data, customized cutting guide was made. This prefabricated cutting guide was used in real mandibuloplasty bilaterally. Premade cutting guide for the mandibuloplasty based on the computer simulation turned out to be very successful in this patient. Individualized approach for each patient could be an ideal way to manage the patients in near future.

• 전자공학회논문지
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• 제53권12호
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• pp.175-179
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• 2016

최근 의료 영상 기술의 발전은 진단, 수술계획, 또는 교육에 도움이 되는 수술 시뮬레이션을 만들어 왔다. 개선된 고화질 영상과 3차원 시각화는 의료 영상 가용성을 향상시키고 수술, 교육 분야에서 더 잘 이용할 수 있게 되었다. 실제 인간의 시각은 입체이다. 따라서, 외과의사의 판단을 통해 2차원 영상을 스테레오로 재구성하여 처리하는 것이 함께 필요하다. 이러한 과정을 줄이기 위해, 3차원 (3D) 이미지가 사용되어 왔다. 3D 영상은 복잡한 상황에서 외과 의사가 매우 짧은 시간에 판단할 수 있도록 3D 시각화를 강화하여 제공한다. 3D 화상 데이터 세트에 기초하여, 가상 내시경 수술 계획, 실시간 상호 작용 가상 의료 시뮬레이션이 가능하게 되었다. 본 논문은 새로운 이미징 기술의 최근 응용 프로그램을 설명하고 이의 기본과 특별히 주목할만한 의료 3D 복원 기술에 관한 것이다. 최근 CT, MR 및 기타 영상 양식의 기술발전은 흥미로운 새로운 솔루션과 어깨 영상의 활용 가능성을 넓혀왔다. 특히, 의료 기기에서 파생 된 3차원 (3D) 이미지는 고급 정보를 제공한다. 이 프레젠테이션은 어깨와 팔꿈치의 수술실습에서 원리, 3D 영상기술의 잠재적 응용가능성, 시뮬레이션, 3D프린팅을 설명한다.

• 대한의용생체공학회:의공학회지
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• 제25권6호
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• pp.497-503
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• 2004

건강한 정상인의 복부대동맥과 장골동맥 분기관의 다이콤 의료 영상으로부터 구성된 혈관 모델을 대상으로 전산혈류해석을 수행하였다. 본 연구에서는 CT로 촬영한 혈관영상으로부터 단면영상을 읽고 각 단면의 경계 좌표를 매끄럽게 추출하는 프로그램을 개발하여 적응하였다. 해석용 3차원 메쉬 생성과 혈류해석은 상용프로그램을 사용하였다. 해석을 통해 얻어진 압력, 속도 및 유량 분포는 정상인의 생리학적 범위 내에 있었다. 초음파로 측정된 장골동맥 중심부의 심장 수축기 속도는 해석에 비해 20% 정도 작은 값을 보였으며 한 주기 동안 속도 변화의 경향은 유사하였다. 본 연구의 접근방법은 환자 개인의 실제 혈관 형상에 기반한 혈류해석으로서 좁아진 동맥 또는 시술 될 동맥에서의 압력, 속도값, 속도분포에 대한 정보를 제공한다. 이 결과는 의사로 하여금 환자의 혈류역학적 변수의 변화를 파악하게 하여 환자의 상태를 더 잘 이해하고 수술의 필요성을 판단하도록 도움을 줄 수 있으며 나아가 혈관 수술의 기초자료로 사용될 수 있을 것이다. 이 연구는 향후 동맥경화와 밀접히 연관된 혈류역학적 변수의 분포를 혈관 내에 보여줌으로서 동맥경화를 조기 진단하는 프로그램으로 발전할 것으로 기대된다.