• Proceedings of the KOSOMBE Conference
• /
• v.1997 no.05
• /
• pp.141-144
• /
• 1997

Femoral neck anteversion is the angle between the neck and the knee axis projected on a plane perpendicular to the longitudinal axis. Conventional methods that use cross-sectional Computed Tomography(CT) images to estimate femoral anteversion have several problems because of the complex 3D structure of the femur. These are the ambiguity of defining the longitudinal axis, the femoral neck axis and condylar line, and the dependence on patient positioning. Especially the femoral neck axis that is known as a major source of error is hard to determine from a single or multiple 2D transverse images. So we developed a new method for measuring femoral anteversion by 3D modeling method. In this method, femoral head is modeled as a sphere. The center of femoral neck is the mid-point of the 2D reconstructed oblique image in the femoral neck part. Then neck axis is a line connecting foregoing two centers. We model the longitude of femur as a cylinder, and the long axis is defined from the fitted cylinder. The knee axis which is tangent to the back of the femoral condyles is easily determined by table-top method. By the definition of femoral anteversion, the femoral anteversion is easily calculated from this model.

• Journal of International Society for Simulation Surgery
• /
• v.4 no.1
• /
• pp.9-12
• /
• 2017

Purpose Surgery for separating craniopagus twins involves many critical issues owing to complex anatomical features. We demonstrate a 3D printed model and virtual reality (VR) technologies that could provide valuable benefits for surgical planning and simulation, which would improve the visualization and perception during craniopagus surgery. Material & Methods We printed a 3D model extracted from CT images of craniopagus patients using segmentation software developed in-house. Then, we imported the 3D model to create the VR environment using 3D simulation software (Unity, Unity Technologies, CA). We utilized the HTC Vive (HTC & Valve Corp) head-mount-display for the VR simulation. Results We obtained the 3D printed model of craniopagus patients and imported the model to a VR environment. Manipulating the model in VR was possible, and the 3D model in the VR environment enhanced the application of user-friendly 3D modeling in surgery for craniopagus twins. Conclusion The use of the 3D printed model and VR has helped understand complicated anatomical structures of craniopagus patients and has made communicating with other medical surgeons in the field much easier. Further, interacting with the 3D model is possible in VR, which enhances the understanding of the craniopagus surgery as well as the success rate of separation surgery while providing useful information on diagnosing and surgery planning.

• Journal of Advanced Marine Engineering and Technology
• /
• v.37 no.8
• /
• pp.862-868
• /
• 2013

The mechanics of woven fabric-based laminated composites is complex. Then, many researchers have studied woven fabric CFRP materials but fracture resistance behaviors for composites have not been still standardized. It also shows the different behavior according to load and fiber direction. Therefore, there is a need to consider fracture resistance behavior in conformity with load and fiber direction at designing structure using woven CFRP materials. In this study, therefore, the tensile strength and resistance for plain-weave CFRP composite materials were investigated under various different angle condition(load to fiber angle: $0^{\circ}$, $15^{\circ}$, $30^{\circ}$, $45^{\circ}$). Tensile strength and fracture toughness tests were carried out under mode I transverse crack opening load by using compact tension specimens.

• Advances in pediatric surgery
• /
• v.13 no.2
• /
• pp.144-154
• /
• 2007

Liver tumors in children are rare, relatively complex, and encompass a broad spectrum of disease processes. This study reviews our experience of liver tumors during the last 10 years. Medical records of 36 cases of liver tumors in children, treated at Samsung Medical Centers, from October 1994 to December 2005, were reviewed in this study. We analyzed disease characters and survival rates as a whole and by specific disease. The median age was 3.6 years. Male and female ratio was 1:1. The most common symptom was the palpable mass in 15 cases. Others were abdominal distension in 9 cases, jaundice in 2, vomiting in 2, weight loss in 2, and pubic hair growth in 1. CT or US and liver biopsy were performed for diagnosis. There were 28 malignant tumors: malignant rhabdoid tumor (1 case), hepatocellular carcinoma (3 cases), hemangioendothelioma type II (3 cases), angiosarcoma (1 case), and hepatoblastoma (20 cases). Eight tumors were benign; hepatic adenoma (1 case), focal nodular hyperplasia (2 cases), hemangioendothelioma type I (2 cases), mesenchymal hamartoma (3 cases). In this study the clinical characteristics were not different from the other reports. Liver transplantation was performed in 3 cases-1 with hepatoblastoma and 2 with hepatocelleular carcinoma. Accurate and early diagnosis, and individualized multimodality therapeutic approaches might be important for better outcome.

• Maxillofacial Plastic and Reconstructive Surgery
• /
• v.22 no.3
• /
• pp.351-355
• /
• 2000

Penetrating injuries in the head and neck region are not common but can pose difficult situations to manage properly. In small cross-sectional area, the neck housed many vital structures, such as carotid artery, internal jugular vein, cervical spines, esophagus, laryngotracheal complex and nerves. Because each vital structure is located within the fascial compartments, bleeding into these closed spaces can give rise to compression of surrounding structures, which may result in compromised airway. Therefore, management of the penetrating injuries should be based on the fully understanding of anatomical relationships, accurate clinical examinations, a careful history taking and the proper treatment planning. We present two cases of penetrating injuries in the head and neck region and discuss on the clinical considerations for the proper management with the literature review.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
• /
• v.47 no.5
• /
• pp.382-387
• /
• 2021

Objectives: Zygomatic complex (ZMC) fractures comprise up to 40% of all facial fractures. Misaligned bone fragments and misplaced fixation hardware traditionally detected postoperatively on plain radiographs of the skull might require re-operation. The intraoperative O-Arm (Medtronic, USA) is a three-dimensional (3D) computed tomographic imaging system. Materials and Methods: This retrospective single-center study evaluated the utility of O-Arm scanning during corrective surgeries for ZMC and zygomatic arch (ZA) fractures from 2018 to 2020. Three females and 16 males (mean age, 31.52 years; range, 22-48 years) were included. Fracture instability (n=6) and facial deformity (n=15) were the most frequent indications for intraoperative 3D O-Arm scan. Results: The images demonstrated that all fracture lines were properly reduced and fixed. Another scan performed at the end of the fixation or reduction stage, however, revealed suboptimal results in five of the 19 cases, and further reduction and fixation of the fracture lines were required. Conclusion: Implementation of an intraoperative O-Arm system in ZMC and ZA fracture surgeries assists in obtaining predictable and accurate results and obviates the need for revision surgeries. The device should be considered for precise operations such as ZMC fracture repairs.

• Korean Journal of Applied Biomechanics
• /
• v.31 no.3
• /
• pp.155-161
• /
• 2021

Objective: There is a lack of studies using the 3D-2D image registration techniques on the mechanism of a shoulder injury for ice hockey players. This study aimed to analyze in vivo 3D glenohumeral joint arthrokinematics in collegiate ice hockey athletes and compare shoulder scaption with or without a hockey stick using the 3D-2D image registration technique. Method: We recruited 12 male elite ice hockey players (age, 19.88 ± 0.65 years). For arthrokinematic analysis of the common shoulder abduction movements of the injury pathogenesis of ice hockey players, participants abducted their dominant arm along the scapular plane and then grabbed a stick using the same motion under C-arm fluoroscopy with 16 frames per second. Computed tomography (CT) scans of the shoulder complex were obtained with a 0.6-mm slice pitch. Data from the humerus translation distances, scapula upward rotation, anterior-posterior tilt, internal to external rotation angles, and scapulohumeral rhythm (SHR) ratio on glenohumeral (GH) joint kinematics were outputted using a MATLAB customized code. Results: The humeral translation in the stick hand compared to the bare hand moved more anterior and more superior until the abduction angle reached 40°. When the GH joint in the stick hand was at the maximal abduction of the scapula, the scapula was externally rotated 2~5° relative to 0°. The SHR ratio relative to the abduction along the scapular plane at 40° indicated a statistically significant difference between the two groups (p < 0.05). Conclusion: With arm loading with the stick, the humeral and scapular kinematics showed a significant correlation in the initial section of the SHR. Although these correlations might be difficult in clinical settings, ice hockey athletes can lead to the movement difference of the scapulohumeral joints with inherent instability.

• Journal of radiological science and technology
• /
• v.41 no.6
• /
• pp.561-566
• /
• 2018

Field-in-Field Technique is applied to the radiation therapy of breast cancer patients, and it is possible to compensate the difference in breast thickness and deliver uniform dose in the breast. However, there are several fields in the treatment field that result in a more complex dose delivery than a single field dose delivery. If the patient's respiration is irregular during the delivery of the dose by several fields and the change of respiration occurs, the dose distribution in the breast changes. Therefore, based on the computed tomography images of breast cancer patients, a human model was created by using a 3D printer (Builder Extreme 1000) to describe the volume in the same manner. A computerized tomography (CT) of the human body model was performed and a treatment plan of 260 cGy / fx was established using a 6-MV field-in-field technique using a computerized treatment planning system (Eclipse 13.6, Varian, USA). The distribution of the dose in the breast according to the change of the respiration was measured using a moving phantom at 0.1 cm, 0.3 cm, 0.5 cm amplitude, using a MOSOXIDE Silicon Field Effect Transistor (MOSFET, Best Medical, Canada) Were measured and compared. The distribution of dose in the breast according to the change of respiration showed similar value within ${\pm}2%$ in the movement up to 0.3 cm compared to the treatment plan. In this experiment, we found that the dose distribution in the breast due to the change of respiration when the change of respiration was increased was not much different from the treatment plan.

• Restorative Dentistry and Endodontics
• /
• v.44 no.2
• /
• pp.16.1-16.12
• /
• 2019

Objectives: The upper molars generally have three roots; therefore, different combinations of fusion can occur, increasing the possibility of finding more complex root canal systems. The purpose of this study was to evaluate the prevalence and characterization of fused roots in first and second maxillary molars using cone-beam computed tomography (CBCT) in a Colombian population. Materials and Methods: A total of 1274 teeth were evaluated, of which 534 were maxillary first molars and 740 were maxillary second molars. Axial sections were made at the cervical, middle, and apical levels to determine the prevalence of root fusion and the types of fusion. Results: Overall, 43% of the molars (n = 551) presented some type of fused root. Root fusion was present in 23.4% of the maxillary first molars. The most frequent type of fused root was type 3 (distobuccal-palatal; DB-P) (58.9%). Root fusion was observed in 57.6% of the maxillary second molars, and the most prevalent type of fused root was type 6 (cone-shaped) (45.2%). Of the maxillary molars, 12.5% were classified as C-shaped. Conclusion: Within the limitations of this study, there was a high prevalence of fused roots in maxillary molars in the Colombian population, mainly in the maxillary second molars. In first molars, the most common type of fused root was type 3 (DB-P) and in second molars, the most common type was type 6 (cone-shaped). Additionally, molars with root fusion presented variation at different levels of the radicular portion, with implications for treatment quality.

• Korean Journal of Microbiology
• /
• v.47 no.2
• /
• pp.117-123
• /
• 2011

The purpose of this study was to evaluate and compare different elution and concentration methods for optimization of human rotavirus (HRV) detection method using real-time RT-PCR and cell culture techniques. The leafy vegetable samples (lettuce, Chinese cabbage) were artificially inoculated with HRV. Viruses were extracted from the vegetables by two different elution buffers, buffer A (100 mM Tris-HCl, 50 mM glycine, 3% beef extract, pH 9.5) and buffer B (250 mM Threonine, 300 mM NaCl, pH 9.5), and the extracted viruses were concentrated by filtration and PEG precipitation sequentially. To determine infectivity of the viruses, the viruses recovered from the samples were infected to the MA-104 cells, and integrated cell culture real-time RT-PCR was performed at 1, 48, 72, 96, 120, 144, 168 h post-infection (p.i.). The elution buffer A was more efficient in extracting the virus from the produce samples tested than the buffer B, 29.54% and 18.32% of recoveries, respectively. The sensitivity of real-time RT-PCR method was markedly improved when the virus was concentrated by the filtration method. When the viruses were eluted and concentrated by buffer A and filtration, respectively, the average recovery rate was approximately 51.89%. When the viruses recovered from samples were infected to MA-104 cell, infectious HRV was detected within 48 h p.i. by ICC/real-time RT-PCR, whereas cytopathic effects were not observed until 72 h p.i. The optimized detection method evaluated in this study could be useful for rapid and reliable detection of HRV in fresh produce products and applied for detection of other food-borne viruses.