• Journal of the Korean Society of Radiology
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• v.7 no.5
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• pp.359-364
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• 2013

Femur is the largest bone in the human body which supports the weight of body. A long pipeline shape of femur has little cancellous bone, so that regeneration is difficult when fracture happens. The fracture caused by an accident most frequently occurs at diaphysis. IM Nailing is the surgical method that implants an IM Nail into a medullary cavity for the fixation of fracture parts. However, a secondary fracture may happen if an IM Nail does not penetrate at the center of femur. In this study, a patient-specific femur was manufactured by a 3D printer using the computed tomography images scanned before surgery, which was used for the simulation of IM Nailing. It is expected that this result may prevent the secondary damage, reduce surgical operation time, and increase the precision.

• Journal of the Institute of Electronics and Information Engineers
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• v.51 no.2
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• pp.173-181
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• 2014

In this paper, the algorithm that can automatically segment the lung, the airway and the pulmonary vessels in a chest CT was proposed. The proposed method is progressed in three steps. In the first step, the lung and the airway are segmented by the region growing law through the optimal threshold and three-dimensional labeling. In the second, from the start point to the first carina of the airway is segmented by the deduction operation, and the next airway of the bifurcations are segmented by applying a variable threshold technique. In the third step, the left/right lungs are divided by the restoration process for the lung, and the outside of lungs for abnormal is checked by applying the advanced rolling ball algorithm, and if abnormal is found, that part is removed, and it is restored to the normal lungs by connecting the outside of the lung in the form of second-order polynomial. Finally, pulmonary vessels are segmented by applying the three-dimensional connected component labeling method and three-dimensional region growing method. As the results of simulation, it could be confirmed that the pulmonary vascular is accurately divided without loss of tissue around lung.

• Journal of the Korea Society of Computer and Information
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• v.19 no.1
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• pp.131-140
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• 2014

TMost of the medical images that are being used today are to confirm the existence of lesions. These kind of medical images can not only be used to confirm lesions but if we could use it for academic studies or for analysis and reference materials for surgical operations, it could offer great help in medical studies. Furthermore, we could reduce the number of errors in treatment through simulations in the surgical operations and treatments. In this paper, the necessary parts regarding the medical image visuals were extracted through the point cloud and by using the information obtained through it, it manufactures the necessary information for academic studies, diagnoses or operations. By designing and realizing the system which makes simulation possible with the manufactured information, the paper attempts to provide a more effective way to approach academic studies or giving appropriate diagnoses in the treatment of patients.

• Radiation Oncology Journal
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• v.11 no.1
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• pp.167-174
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• 1993

Recently, stereotactic radiosurgery plan is required with the information of 3-D image and dose distribution. A project has been doing if developing LINAC based stereotactic radiosurgery since April 1991. The purpose of this research is to develop 3-D radiosurgery planning system using personal computer. The procedure of this research is based on two steps. The first step is to develop 3-D localization system, which input the image information of the patient, coordinate transformation, the position and shape of target, and patient contour into computer system using CT image and stereotactic frame. The second step is to develop 3-D dose planning system, which compute dose distribution on image plane, display on high resolution monitor both isodose distribution and patient image simultaneously and develop menu-driven planning system. This prototype of radiosurgery planning system was applied recently for several clinical cases. It was shown that our planning system is fast, accurate and efficient while making it possible to handle various kinds of image modalities such as angiography, CT and MRI. It makes it possible to develop general 3-D planning system using beam's eye view or CT simulation in radiation therapy in future.

• Radiation Oncology Journal
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• v.31 no.1
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• pp.12-17
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• 2013

Purpose: Parotid gland can be considered as a risk organ in whole brain radiotherapy (WBRT). The purpose of this study is to evaluate the parotid gland sparing effect of computed tomography (CT)-based WBRT compared to 2-dimensional plan with conventional field margin. Materials and Methods: From January 2008 to April 2011, 53 patients underwent WBRT using CT-based simulation. Bilateral two-field arrangement was used and the prescribed dose was 30 Gy in 10 fractions. We compared the parotid dose between 2 radiotherapy plans using different lower field margins: conventional field to the lower level of the atlas (CF) and modified field fitted to the brain tissue (MF). Results: Averages of mean parotid dose of the 2 protocols with CF and MF were 17.4 Gy and 8.7 Gy, respectively (p < 0.001). Mean parotid dose of both glands ${\geq}20$ Gy were observed in 15 (28.3%) for CF and in 0 (0.0%) for MF. The whole brain percentage volumes receiving >98% of prescribed dose were 99.7% for CF and 99.5% for MF. Conclusion: Compared to WBRT with CF, CT-based lower field margin modification is a simple and effective technique for sparing the parotid gland, while providing similar dose coverage of the whole brain.

• Journal of the Korean Society of Radiology
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• v.15 no.7
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• pp.957-964
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• 2021

Fluorine-18 used in PET/CT scans is a radioactive isotope that emits positrons, and high energy annihilation gamma rays and beta rays cause exposure to radiation workers. In this study, as part of a plan to reduce the exposure dose of radiation workers working in the Department of Nuclear Medicine, the cause of the low shielding efficiency of Apron for F-18 was identified, and the effectiveness of the Apron double-shielded with acrylic was evaluated. L-Block, Apron+acrylic, Apron, Acrylic+Apron, and Acrylic five shields are used to measure the dose, and the tendencies were compared by performing a Monte Carlo simulation. As a result, it was found that the shielding rate of Apron double shielded with acrylic was about 4 to 8% higher than that of Apron single shielded. To the extent that it does not significantly affect the user's activity, double-shielded personal protective clothing with an appropriate acrylic thickness could help reduce radiation workers' exposure.

• Nuclear Engineering and Technology
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• v.54 no.11
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• pp.4244-4252
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• 2022

The accuracy of Monte Carlo (MC) simulations in estimating the computed tomography radiation dose is highly dependent on the accuracy of CT scanner model. A system was developed to observe the 3D model intuitively and to calculate the X-ray energy spectrum and the bowtie (BT) filter model more accurately in Monte Carlo N-particle (MCNP). Labview's built-in Open Graphics Library (OpenGL) was used to display basic surfaces, and constructive solid geometry (CSG) method was used to realize Boolean operations. The energy spectrum was calculated by simulating the process of electronic shooting and the BT filter model was accurately modeled based on the calculated shape curve. Physical data from a study was used as an example to illustrate the accuracy of the constructed model. RMSE between the simulation and the measurement results were 0.97% and 0.74% for two filters of different shapes. It can be seen from the comparison results that to obtain an accurate CT scanner model, physical measurements should be taken as the standard. The energy spectrum library should be established based on Monte Carlo simulations with modifiable input files. It is necessary to use the three-segment splicing modeling method to construct the bowtie filter model.

• Journal of IKEEE
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• v.12 no.3
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• pp.158-166
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• 2008

Medical ultrasound has benefits in mobility and safety than any other medical techniques such as X-ray, CT and MRI but has speckle noise which decrease the ability of an observer to distinguish the fine details in diagnostic examination. But simple removing of speckle often causes losing boundary information. Then, in this paper, we presented a novel neuro-fuzzy method which could remove speckle efficiently without loss of boundary information. Proposed method consists of image clustering by fuzzy algorithm and image processingby neural networks which was learned by back propagation. From the experiments for simulation image and real ultrasound image, we could verify the proposed method.

• Journal of Korea Multimedia Society
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• v.23 no.9
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• pp.1129-1138
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• 2020

The performance of convolutional deep learning networks is generally determined according to parameters of target dataset, structure of network, convolution kernel, activation function, and optimization algorithm. In this paper, a genetic algorithm is used to select the appropriate deep learning model and parameters for Alzheimer's classification and to compare the learning results with preliminary experiment. We compare and analyze the Alzheimer's disease classification performance of VGG-16, GoogLeNet, and ResNet to select an effective network for detecting AD and MCI. The simulation results show that the network structure is ResNet, the activation function is ReLU, the optimization algorithm is Adam, and the convolution kernel has a 3-dilated convolution filter for the accuracy of dementia medical images.

• Journal of Korean Society of Water and Wastewater
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• v.28 no.4
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• pp.431-440
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• 2014

The ozonation process has been widely used for drinking water disinfection around the world. Recently, the pressurized ozone contactor, in which the side stream typed ozone injection method is installed, has been applied to water treatment system. In this study, numerical calculations were conducted to compare prototype and screw-type ozone contactors based on hydraulic effectiveness in more details. The prototype ozone contactor was already installed and operated in domestic water treatment plant, and the screw-type is the suggested one for improving ozone contact efficiency installing the screw plate to the prototype. Screw turn numbers of screw plate were changed as 3, 5, 7 and 9, respectively for numerical simulation. The CT(concentration of disinfectant in mg/L times time in minutes) value was considered as one of the options for evaluating disinfection ability. From the results, it could be concluded that the performance of the screw-type is higher than that of the protype contactor by controlling the variable T as the tracer time. Also, Morill index of the screw-type(turn numbers = 5 ) appeared to be lower than the other.