• Imaging Science in Dentistry
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• v.40 no.2
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• pp.63-68
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• 2010

Purpose : To compare the CT numbers on 3 cone-beam CT (CBCT) images with those on multi-detector CT (MDCT) image using CT phantom and to develop linear regressive equations using CT numbers to material density for all the CT scanner each. Materials and Methods : Mini CT phantom comprised of five 1 inch thick cylindrical models with 1.125 inches diameter of materials with different densities (polyethylene, polystyrene, plastic water, nylon and acrylic) was used. It was scanned in 3 CBCTs (i-CAT, Alphard VEGA, Implagraphy SC) and 1 MDCT (Somatom Emotion). The images were saved as DICOM format and CT numbers were measured using OnDemand 3D. CT numbers obtained from CBCTs and MDCT images were compared and linear regression analysis was performed for the density, $\rho$ ($g/cm^3$), as the dependent variable in terms of the CT numbers obtained from CBCTs and MDCT images. Results : CT numbers on i-CAT and Implagraphy CBCT images were smaller than those on Somatom Emotion MDCT image (p<0.05). Linear relationship on a range of materials used for this study were $\rho$=0.001H+1.07 with $R^2$ value of 0.999 for Somatom Emotion, $\rho$=0.002H+1.09 with $R^2$ value of 0.991 for Alphard VEGA, $\rho$=0.001H+1.43 with $R^2$ value of 0.980 for i-CAT and $\rho$=0.001H+1.30 with $R^2$ value of 0.975 for Implagraphy. Conclusion: CT numbers on i-CAT and Implagraphy CBCT images were not same as those on Somatom Emotion MDCT image. The linear regressive equations to determine the density from the CT numbers with very high correlation coefficient were obtained on three CBCT and MDCT scan.

• Journal of the Korean Society of Radiology
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• v.14 no.2
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• pp.111-120
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• 2020

Research should be actively conducted for the ability of X-ray equipment and Retrospective image analysis of X-ray equipment used in hospitals. Retrospective image analysis of X-ray machines, CT and MRI of radiology and medical equipment has been actively conducted. However, image quality measurement using angiography equipment of angiography room is mostly measured with phantom, and image quality measurement on image after being taken by actual patient is insufficient and researches on accurate image quality measurement method are remarkable. It is in short supply. Therefore, through this study, the researcher devised a method to measure the image quality of the acquired image after coronary angiography, and to provide a high quality image to the operator. The equipment and programs used were angiographic examination equipment (Axiom Artis Zee Ceiling) and Image J program. Subjects were images automatically saved in PACS program after coronary angiography.For image quality measurement, selected the AP Caudal 30° image that show the LCA vessel well and the LAO 30° image that show the RCA vessel well during the coronary angiography. In order to measure the background and ROI of the selected image by selecting an image, a criterion on how to find and measure a section where the overlap of the shadow, such as blood vessel, liver and lung is minimized, is presented. In conclusion, there is no exact standard for analyzing an image quality measurement method of angiography image. Therefore, in order to provide quality images to the practistioners, not only the technicians of the equipment but also the users who actually use them should become researchers and conduct research on image quality measurement in various ways. Thus, it is expected to provide excellent images to patients.

• Economic and Environmental Geology
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• v.56 no.3
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• pp.293-300
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• 2023

The Shape Preferred Orientation (SPO) method has been used to analyze the orientation of fault motion, which is utilized as basic data for fault kinematics studies. The rigid grains, which as quartz, feldspar, and rock fragments, in the fault gouge are arranged in the P-shear direction through rigid body rotation by a given shear stress. Using this characteristic, the fault motion can be estimated from the SPO inversely. Recently, a method for securing precision and reliability by measuring 3D-SPO using X-ray CT images and examining the shape of a large number of particles in a short time has been developed. As a result, the SPO method analyzes the orientation of thousands to tens of thousands of particles at high speed, suggests the direction of fault motion, and provides easy accessibility and reliable data. In addition, the shape information and orientation distribution data of particles, which are by-products obtained in the SPO analysis process, are expected to be used as basic data for conducting various studies such as the local deformation of fault rocks and the fault generation mechanism.

• Asian Pacific Journal of Cancer Prevention
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• v.17 no.10
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• pp.4599-4608
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• 2016

Background: The x-ray repair cross-complementing group 3 (XRCC3) encodes a protein involved in the homologous recombination repair (HRR) pathway for double-strand DNA repair. Associations of the XRCC3 Thr241Met polymorphism with various cancers have been widely reported. However, published data on links between XRCC3 Thr241Met and gastrointestinal (GI) cancer risk are inconsistent. Objective and Methods: A meta-analysis was conducted to characterize the relationship between XRCC3 Thr241Met polymorphisms and GI cancer risk. Pooled odds ratios (ORs) and 95.0% confidence intervals were assessed using random- or fixed- effect models for 28.0 relevant articles with 30.0 studies containing 7,649.0 cases and 11,123.0 controls. Results: The results of the overall meta-analysis suggested a borderline association between the XRCC3 Thr241Met polymorphism and GI cancer susceptibility (T vs. C: OR=1.18, 9 % CI=1.0-1.4, POR=0.04; TT vs. CT+CC: OR=1.3, 95 % CI=1.0-1.6, POR=0.04). After removing studies not conforming to Hardy-Weinberg equilibrium (HWE), however, this association disappeared (T vs. C: OR=1.00, 95 % CI=0.9-1.1, POR=0.96; TT vs. CT+CC: OR=0.9, 95 % CI=0.8-1.1, POR=0.72). When stratified by ethnicity, source of controls or cancer type, although some associations between XRCC3 Thr241Met polymorphism and GI cancer susceptibility were detected, these associations no longer existed after removing studies not conforming to HWE. Conclusion: Our meta-analysis suggests that the XRCC3 Thr241Met polymorphism is not associated with risk of GI cancer based on current evidence.

• Journal of Korean Neurosurgical Society
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• v.49 no.5
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• pp.267-272
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• 2011

Objective : Although iliac crest autograft is the gold standard for lumbar fusion, the morbidity of donor site leads us to find an alternatives to replace autologous bone graft. Ceramic-based synthetic bone grafts such as hydroxyapatite (HA) and b-tricalcium phosphate (b-TCP) provide scaffolds similar to those of autologous bone, are plentiful and inexpensive, and are not associated with donor morbidity. The present report describes the use of Polybone$^{(R)}$ (Kyungwon Medical, Korea), a beta-tricalcium phosphate, for lumbar posterolateral fusion and assesses clinical and radiological efficacy as a graft material. Methods : This study retrospectively analyzed data from 32 patients (11 men, 21 women) who underwent posterolateral fusion (PLF) using PolyBone$^{(R)}$ from January to August, 2008. Back and leg pain were assessed using a Numeric Rating Scale (NRS), and clinical outcome was assessed using the Oswestry Disability Index (ODI). Serial radiological X-ray follow up were done at 1, 3, 6 12 month. A computed tomography (CT) scan was done in 12 month. Radiological fusion was assessed using simple anterior-posterior (AP) X-rays and computed tomography (CT). The changes of radiodensity of fusion mass showed on the X-ray image were analyzed into 4 stages to assess PLF status. Results : The mean NRS scores for leg pain and back pain decreased over 12 months postoperatively, from 8.0 to 1.0 and from 6.7 to 1.7, respectively. The mean ODI score also decreased from 60.5 to 17.7. X-rays and CT showed that 25 cases had stage IV fusion bridges at 12 months postoperatively (83.3% success). The radiodensity of fusion mass on X-ray AP image significantly changed at 1 and 6 months. Conclusion: The present results indicate that the use of a mixture of local autologous bone and PolyBone$^{(R)}$ results in fusion rates comparable to those using autologous bone and has the advantage of reduced morbidity. In addition, the graft radiodensity ratio significantly changed at postoperative 1 and 6 months, possibly reflecting the inflammatory response and stabilization.

• Journal of Korean Neurosurgical Society
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• v.52 no.6
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• pp.528-533
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• 2012

Objective : In the pediatric population the skull has not yet undergone ossification and it is assumed that the diagnostic rate of skull fractures by simple X-rays are lower than that of adults. It has been recently proposed that the diagnostic rates of skull fractures by 3-dimensional computer tomography (3D-CT) are higher than simple X-rays. The authors therefore attempted to compare the diagnostic rates of pediatric skull fractures by simple X-rays and 3D-CTs with respect to the type of fracture. Methods : One-hundred patients aged less than 12 years who visited the Emergency Center for cranial injury were subject to simple X-rays and 3D-CTs. The type and location of the fractures were compared and Kappa statistical analysis and the t-test were conducted. Results : Among the 100 pediatric patients, 65 were male and 35 were female. The mean age was $50{\pm}45$ months. 63 patients had simple skull fractures and 22 had complex fractures, and the types of fractures were linear fractures in 74, diastatic fractures 15, depressed fractures in 10, penetrating fracture in 1, and greenstick fractures in 3 patients. Statistical difference was observed for the predictive value of simple skull fractures' diagnostic rate depending on the method for diagnosis. A significant difference of the Kappa value was noted in the diagnosis of depressed skull fractures and diastatic skull fractures. Conclusion : In the majority of pediatric skull fractures, 3D-CT showed superior diagnosis rates compared to simple skull X-rays and therefore 3D-CT is recommended whenever skull fractures are suspected. This is especially true for depressed skull fractures and diastatic skull fractures.

• Journal of Chest Surgery
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• v.30 no.11
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• pp.1055-1061
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• 1997

In the field of the experimental lung transplantation, we analyzed the CT findings of acute rejection, infection in the left single allotransplanted lung of adult mongrel dogs, and the CT findings were compared with the histological findings obtained by the lung biopsy Twenty two adult mongrel dogs were divided into two groups(Donor and recipient group). Donor lungs were flushed with LPDG(low pota,ilium dextral glucose) solution(n=4) or modified Euro-collins solution(n=7) and preserved over 20 hours with $10^{\circ}C(1$ case preservation for 4hours). After left single lung transplantation, the chest X-ray and sequential computed tomogram were performed with concomitant hemodynamic study and arterial blood gas analysis on immediate postoperative period, postoperative 3rd day and postoperative 7th day. Two of eleven transplanted lungs had acute rejection which was represented as moderate infiltration at immediate or 1st postoperative d y but became extensive infiltration at postoperative 3rd day on CT. There were showed one case of bronchopleural fistula, six cases of pneumonia and two cases of pulmonary infarction. In one rejection cases, the opacity of transplanted lung was improved by injection of methylprednisolone 500mg daily during 3 days. We concluded that CT was a useful noninvasive evaluation parameter after lung transplantation and the serial CT scan enabled early detection of acute rejection.

• 제어로봇시스템학회:학술대회논문집
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• 2003.10a
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• pp.53-56
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• 2003

For identifying how a sample knit fabric is woven a method to obtain positional information of each yarn of the sample from voxel data made out of its x-ray CT images is newly proposed in this paper. The positional information is obtained by tracing the each yarn. The each yarn is traced by estimating a direction of the yarn in a certain small region in which the yarn can be regarded as straight and moving the region slightly along the estimated direction alternately. The yarn direction is estimated by correlating the voxel data in the region with a three-dimensional yarn model. The effectiveness of this method is confirmed by applying the method to voxel data made out of CT images of a knit fabric experimentally.

• Journal of the Korean Society of Radiology
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• v.82 no.4
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• pp.808-816
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• 2021

Pulmonary emphysema is a cause of chronic obstructive pulmonary disease. Emphysema can be accurately diagnosed via CT. The severity of emphysema can be assessed using visual interpretation or quantitative analysis. Various studies on emphysema using deep learning have also been conducted. Although the classification of emphysema has proven clinically useful, there is a need to improve the reliability of the measurement.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.53 no.3
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• pp.164-172
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• 2004

This paper presents the comparison results of some kinds of control method in circumstance of eccentric load. The plant to be controlled is a computed tomography(CT) driven by a permanent magnet synchronous motor. In a CT system, many units are attached on the rotationally part of a gantry such as x-ray tube, detector, heat exchanger, and data acquisition unit etc. Therefore keeping many components to balance which have different weight is not easy; this is inescapable problem in the all CT systems. To solve this problem against eccentric load, some kinds of control method have been compared and analysed by using protype CT. From the experimental results it is vilified that the CT drive system with model reference control method indicates higher speed regulation ability regardless of variable eccentric weight and uncertain position, and also in the limit condition of constant eccentric weight and fixed position, the compensation method with sinusoidal form is a strong candidate in view of speed ripple reduction.