• The Korean Journal of Nuclear Medicine Technology
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• v.27 no.1
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• pp.47-54
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• 2023

Purpose PET-CT imaging require an appropriate quality assurance system to achieve high efficiency and reliability. Quality control is essential for improving the quality of care and patient safety. Currently, there are performance evaluation methods of UN2-1994 and UN2-2001 proposed by NEMA and IEC for PET-CT image evaluation. In this study, we compare phantom images with the same experiments before and after PET-CT 3D normalization and well counter correction and evaluate the usefulness of quality control. Materials and methods Discovery 690 (General Electric Healthcare, USA) PET-CT equiptment was used to perform 3D normalization and well counter correction as recommended by GE Healthcare. Based on the recovery coefficients for the six spheres of the NEMA IEC Body Phantom recommended by the EARL. 20kBq/㎖ of ¹⁸F was injected into the sphere of the phantom and 2kBq/㎖ of ¹⁸F was injected into the body of phantom. PET-CT scan was performed with a radioacitivity ratio of 10:1. Images were reconstructed by appliying TOF+PSF+TOF, OSEM+PSF, OSEM and Gaussian filter 4.0, 4.5, 5.0, 5.5, 6.0, 6,5 mm with matrix size 128×128, slice thickness 3.75 mm, iteration 2, subset 16 conditions. The PET image was attenuation corrected using the CT images and analyzed using software program AW 4.7 (General Electric Healthcare, USA). The ROI was set to fit 6 spheres in the CT image, RC (Recovery Coefficient) was measured after fusion of PET and CT. Statistical analysis was performed wilcoxon signed rank test using R. Results Overall, after the quality control items were performed, the recovery coefficient of the phantom image increased and measured. Recovery coefficient according to the image reconstruction increased in the order TOF+PSF, TOF, OSEM+PSF, before and after quality control, RCmax increased by OSEM 0.13, OSEM+PSF 0.16, TOF 0.16, TOF+PSF 0.15 and RCmean increased by OSEM 0.09, OSEM+PSF 0.09, TOF 0.106, TOF+PSF 0.10. Both groups showed a statistically significant difference in Wilcoxon signed rank test results (P value<0.001). Conclusion PET-CT system require quality assurance to achieve high efficiency and reliability. Standardized intervals and procedures should be followed for quality control. We hope that this study will be a good opportunity to think about the importance of quality control in PET-CT

• Journal of the Korean Orthopaedic Association
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• v.52 no.1
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• pp.65-72
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• 2017

Purpose: The purpose of this study was to evaluate the radiologic features of juxtafacet cyst and determine the correlation between these features and clinical outcome. Materials and Methods: We analyzed a total of 23 patients. The degree of facet joint degeneration was classified using the Fujiwara method. The facet joint angles were measured with an magnetic resonance imaging to determine whether there was a difference between the cystic lesion that was occupied and the cystic lesion that was not occupied. Disc degeneration was measured by the Pfirrmann classification method. The clinical result was evaluated using the Oswestry disability index score and visual analogue scale. Results: The L4-5 level of juxtafacet cyst was mostly affected, as found in previous studies. Facet joint arthritis was more severe within the side with the cystic lesion. Significant correlation was found between disc degeneration and juxtafacet joint cyst. All patients underwent wide decompression and fusion. Clinical result was excellent. No patients had signs of recurrence during the follow-up periods. Conclusion: Juxtafacet cyst has a significant correlation with facet joint degeneration. Therefore, aggressive surgical treatment-not just simple cyst excision-should be considered as the treatment option for juxtafacet cyst associated with degenerative lumbar disease.

• Asia-pacific Journal of Multimedia Services Convergent with Art, Humanities, and Sociology
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• v.7 no.6
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• pp.897-906
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• 2017

Projection Mapping, also known as Spatial Augmented Reality(SAR) has attracted much attention recently and used for many division, which can augment physical objects with projected various virtual replications. However, conventional approaches towards projection mapping have faced some limitations. Target objects' geometric transformation property does not considered, and movements of flexible objects-like paper are hard to handle, such as folding and bending as natural interaction. Also, precise registration and tracking has been a cumbersome process in the past. While there have been many researches on Projection Mapping on static objects, dynamic projection mapping that can keep tracking of a moving flexible target and aligning the projection at interactive level is still a challenge. Therefore, this paper propose a new method using Unity3D and ARToolkit for high-speed robust tracking and dynamic projection mapping onto non-rigid deforming objects rapidly and interactively. The method consists of four stages, forming cubic bezier surface, process of rendering transformation values, multiple marker recognition and tracking, and webcam real time-lapse imaging. Users can fold, curve, bend and twist to make interaction. This method can achieve three high-quality results. First, the system can detect the strong deformation of objects. Second, it reduces the occlusion error which reduces the misalignment between the target object and the projected video. Lastly, the accuracy and the robustness of this method can make result values to be projected exactly onto the target object in real-time with high-speed and precise transformation tracking.

• Asia-pacific Journal of Multimedia Services Convergent with Art, Humanities, and Sociology
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• v.8 no.10
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• pp.63-70
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• 2018

Biomedical signal measurement technology using images has been developed, and researches on respiration signal measurement technology for maintaining life have been continuously carried out. The existing technology measured respiratory signals through a thermal imaging camera that measures heat emitted from a person's body. In addition, research was conducted to measure respiration rate by analyzing human chest movement in real time. However, the image processing using the infrared thermal image may be difficult to detect the respiratory organ due to the external environmental factors (temperature change, noise, etc.), and thus the accuracy of the measurement of the respiration rate is low.In this study, the images were acquired using visible light and infrared thermal camera to enhance the area of the respiratory tract. Then, based on the two images, features of the respiratory tract region are extracted through processes such as face recognition and image matching. The pattern of the respiratory signal is classified through the k-nearest neighbor classifier, which is one of the statistical classification methods. The respiration rate was calculated according to the characteristics of the classified patterns and the possibility of breathing rate measurement was verified by analyzing the measured respiration rate with the actual respiration rate.

• Journal of Korean Neurosurgical Society
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• v.66 no.4
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• pp.446-455
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• 2023

Objective : Chronic subdural hematoma (CSDH) is a common neurosurgical disease and generally treated with burr-hole surgery alone. Tranexamic acid (TXA) is an antifibrinolytic agent that potentially reduces recurrence rates and the residual hematoma volume. However, the role of postoperative TXA medication remains unclear to date. This study aimed to verify the effectiveness of adjunctive TXA in the view of early hematoma resolution. Methods : Between January 2018 and September 2021, patients with CSDH who underwent burr-hole trephination in a single tertiary institute were reviewed. The study population was divided into three groups, TXA, non-TXA, and antithrombotics (AT) groups, according to the medical history of cardio-cerebrovascular disease and TXA administration. The primary endpoint was CSDH recurrence, defined as re-appearance or re-accumulation of CSDH requiring neurosurgical interventions. The secondary outcome was CSDH resolution, defined as complete or near-complete resorption of the CSDH. The CSDH resolution time and serial changes of hematoma thickness were also investigated. Results : A total of 240 patients was included in the analysis consisting of 185 male and 55 female, with a median age of 74 years. During the median imaging follow-up period of 75 days, 222 patients were reached to the primary or secondary endpoint. TXA was administered as an adjunctive therapy in 41 patients (TXA group, 16.9%) while 114 patients were included in the non-TXA group (47.9%) and 85 were in the AT group. The recurrence rate was the lowest in the TXA group (2.4%), followed by non-TXA (7.0%) and AT (8.2%) groups. However, there was no statistical significance due to the small number of patients with recurrence. CSDH resolution was achieved in 206 patients, and the median estimated time to resolution was significantly faster in the TXA group (p<0.001). Adjunctive TXA administration was a significant positive factor for achieving CSDH resolution (p<0.001). The hematoma thickness was comparable among the three groups at the initial time and after surgery. However, CSDH thickness in the TXA group decreased abruptly in a month and showed a significant difference from that in the other groups (p<0.001). There was no TXA-related adverse event. Conclusion : The adjunctive use of TXA after CSDH surgery significantly facilitated the resorption of residual CSDH and resulted in the early CSDH resolution. Adjunctive TXA may be an effective treatment option to reduce recurrence by enhancing CSDH resolution in the selective patients.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.29 no.1D
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• pp.135-143
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• 2009

Integrating the Global Positioning System (GPS) and Inertial Navigation System (INS) sensor technologies using the precise GPS Carrier phase measurements is a methodology that has been widely applied in those application fields requiring accurate and reliable positioning and attitude determination; ranging from 'kinematic geodesy', to mobile mapping and imaging, to precise navigation. However, such integrated system may not fulfil the demanding performance requirements when the baseline length between reference and mobil user GPS receiver is grater than a few tens of kilometers. This is because their positioning/attitude determination is still very dependent on the errors of the GPS observations, so-called "baseline dependent errors". This limitation can be remedied by the integration of GPS and INS sensors, using multiple reference stations. Hence, in order to derive the GPS distance dependent errors, this research proposes measurement processing algorithms for multiple reference stations, such as a reference station ambiguity resolution procedure using linear combination techniques, a error estimation based on Kalman filter and a error interpolation. In addition, all the algorithms are evaluated by processing real observations and results are summarized in this paper.

• Journal of Life Science
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• v.33 no.7
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• pp.574-585
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• 2023

Sarcopenia is a leading cause of increased medical and nursing care costs among the elderly. In Korea, preventive measures for sarcopenia are mostly targeted toward the general elderly population without specific diseases. However, it is also necessary to implement measures for elderly individuals living in nursing homes and hospitals, where the prevalence of sarcopenia is high. Currently, computed tomography and/or magnetic resonance imaging are considered standard diagnostic tools. However, their complexity and time-consuming nature make them unsuitable for clinical use. The exact pathophysiological mechanisms of sarcopenia are unclear, as they involve various molecular biological pathways, including decreased exercise, protein and nutrient intake, changes in testosterone and growth hormone, and inflammation. Sarcopenia symptoms can lead to several diseases, such as osteoporosis, fractures, dementia, diabetes, and cardiovascular disease. Vitamin B deficiency is a significant factor in sarcopenia induction, with B vitamins being directly involved in energy and protein metabolism and nerve function. Vitamin B deficiency can lead to neuromuscular and neurogenic disorders, which often overlap with sarcopenia. Suboptimal intake of B vitamins, malabsorption, and anorexia are common among the elderly. This study aims to provide information on the role of water-soluble B vitamins in preventing and controlling muscle mass loss and deterioration among the elderly with sarcopenia. In addition, we discuss the potential of myokines from the B vitamin family in modulating sarcopenia.

• Convergence Security Journal
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• v.22 no.5
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• pp.21-35
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• 2022

The use of digital information according to the development of information and communication technology and the 4th industrial revolution is continuously increasing and diversifying, and in proportion to this, crimes using digital information are also increasing. However, there are few cases of establishing an environment for processing and analysis of digital evidence in Korea. The budget allocated for each organization is different and the digital forensics laboratory built without solving the chronic problem of securing space has a problem in that there is no standard that can be referenced from the initial configuration stage. Based on this awareness of the problem, this thesis conducted an exploratory study focusing on tools and equipment necessary for building a digital forensics laboratory. As a research method, focus group interviews were conducted with 15 experts with extensive practical experience in the digital forensic laboratory or digital forensics field and experts' opinions were collected on the following 9 areas: network configuration, analyst computer, personal tools·equipment, imaging devices, dedicated software, open source software, common tools/equipment, accessories, and other considerations. As a result, a list of tools and equipment for digital forensic laboratories was derived.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.30 no.5B
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• pp.459-469
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• 2010

This study is to develop a grid-based daily runoff model considering seasonal vegetation canopy condition. The model simulates the temporal and spatial variation of runoff components (surface, interflow, and baseflow), evapotranspiration (ET) and soil moisture contents of each grid element. The model is composed of three main modules of runoff, ET, and soil moisture. The total runoff was simulated by using soil water storage capacity of the day, and was allocated by introducing recession curves of each runoff component. The ET was calculated by Penman-Monteith method considering MODIS leaf area index (LAI). The daily soil moisture was routed by soil water balance equation. The model was evaluated for 930 $km^2$ Yongdam watershed. The model uses 1 km spatial data on landuse, soil, boundary, MODIS LAI. The daily weather data was built using IDW method (2000-2008). Model calibration was carried out to compare with the observed streamflow at the watershed outlet. The Nash-Sutcliffe model efficiency was 0.78~0.93. The watershed soil moisture was sensitive to precipitation and soil texture, consequently affected the streamflow, and the evapotranspiration responded to landuse type.

• Journal of Korea Entertainment Industry Association
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• v.13 no.6
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• pp.123-133
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• 2019

Director Lee Chang-dong saying that the most important thing is to let the audience experience, find its meaning, interpret, and feel the pure sensation (whether it's image, sound or music) that the film has instead of narrative giving you the answers, through the film presenting the pure natural landscape as it is, but all the familiar things that can be taken as a riddle are conveyed in images, and all the elements that make up the film share its presence with each other and let us experience a mysterious weight of reality that cannot be defined through its strange symbolism and metaphors, and it reflects various human emotions, reflecting curiosity of reality, the words that are hardly spoken, meanings of life that we were not being aware of. Rather than having one definitive figure, through the character's personality expressing an imperfect character with a complex ambiguous behavior asks about the things that can't be explained logically and the fact of life that can't be divided into truth or lie. Also, the acting approaches emotionally and primitively rather than using artificial expressions, showing the invisible elements of emotions that are latent inside humans through temperate acting style, leads the audience to distant themselves and reflect more deeply into life. This study analyzed the characters and acting of the film based on director Lee Chang-dong's directing style.