• Journal of Korea Multimedia Society
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• v.19 no.1
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• pp.1-9
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• 2016

In this paper, we propose a method of measuring bone mineral density in a peripheral-type clinical X-ray CT using a phantom, and we propose a method of classifying osteoporosis using bone mineral density and bone structure parameters together. It segments the trabecular bone region and cortical bone region for the six sections of the phantom and calculates the average HU value of the segmented regions. By using these values, it derives an expression converting HU value to bone mineral density. It segments trabecular bone of 1 cm region in the end part of distal radius and extracts the bone mineral density and structural parameters for the trabecular bone region. We extracted bone mineral density and structural parameters for the 18 subjects each of normal and osteoporotic group. We carried out classification experiments using three classification methods; SAD, SVM, ANN. The sensitivity, specificity, accuracy, positive predictive value, negative predictive value, likelihood ratio of the classification was improved in the order of ANN, SVM and SAD. Also, The sensitivity, specificity, accuracy, positive predictive value, negative predictive value, likelihood ratio of the classification was improved when we use the bone mineral density and structural parameters together.

• Journal of Biomedical Engineering Research
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• v.20 no.2
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• pp.139-148
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• 1999

In this paper, we designed the dental surgery system based on PC. This system predict post operated 3-dimensional image, So the patient has no need to take CT after surgery and expose his body to radiological damage. We predict the post operated skull from the patient's CT with pre and post cephalometry X-ray. Our novel procedures, to register X-ray and CT, are based on anatomical landmarks, singular value decomposition. And we display the predicted image 3-dimensionally by surface rendering. We verified this system by dry skull experiment and clinical experiment. When significance level is 0.05, there is on significance.

• Korean journal of food and cookery science
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• v.32 no.2
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• pp.211-221
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• 2016

Purpose: This study was conducted to investigate the physical and sensory properties of seasoned powders utilizing tomato. Methods: Tests of salted tomato powder were performed for the physiochemical properties (moisture content, pH value, titratable acidity, color value, salinity content, and solubility content), sensory characteristics and sensory preference. Results: Moisture content of salted tomato powder containing fully ripened tomato (RT) was higher than that of salted tomato powder containing cherry tomato (CT), with the exception of CT 10%. The pH values of RT was relatively high and increased salt addition increased the pH as well. The titratable acidity was opposite the result of pH measurement. The color values of RT was higher than that of CT for the L, a, and b values. The salt content of RT was higher than that of CT. RT 10% showed the highest dissolution followed by CT 10%. In addition, the sensory preference for CT 10% was the highest, with the best scores for appearance and taste. Conclusion: It was concluded that 10% salt addition is the most suitable sensually for the manufacture of salted tomato powder.

• The Journal of the Korea Contents Association
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• v.11 no.10
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• pp.333-341
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• 2011

To compare between calcium scoring CT (CSCT) and Low-dose CT (LDCT) image finding for coronary artery calcification (CAC) in screening of lung disease by MDCT. A total of 61 subjects who retired-workers exposed to inorganic dust were performed LDCT and CSCT by using a MDCT scanner on the same day, after be approved by the institutional review board, and obtaining the written informed consent from all subjects. LDCT images were read for detecting lung diseases as well as CAC by a experienced chest radiologist, then the subjects were divided either the positive group with CAC or the negative group without it. The CSCT was used to quantify and detect the presence of calcification in the coronary artery, and score of CAC calculated by using a Rapidia software (ver 2.8). In all coronary arteries, calcium score of positive group was higher better than that in negative group, especially in the total calcium (13.7 vs. 582.9, p=0.008) and the left anterior descending artery (3.2 vs. 249.0, p=0.006). CAC findings between CSCT and LDCT image were showed excellent agreement in cut-off point 100(K-value=0.80, 95% CI=0.69-0.91) from total calcium score. CAC findings on LDCT images showed the higher relation with CSCT. Therefore, the obstructive coronary artery disease could be predicted by CAC on LDCT images for screening of lung diseases.

• Journal of Korea Multimedia Society
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• v.9 no.8
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• pp.1086-1094
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• 2006

The CT is all relation knowledge and technology which are applied to make the culture contents. Recently demand regarding the CT is increasing rapidly with a great growth and high technology of culture contents industry. In this paper we suggest a CT technology valuation model for promoting R & D results and technical diffusion of the CT. Also, It is shown how to derive a value of the CT using simulation. For it, we study a classification and distinctive characteristics of the CT. And this paper reviews the methods of technology valuation that have been developed by valuation specialists.

• Journal of Gastric Cancer
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• v.8 no.4
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• pp.250-255
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• 2008

Purpose: The purpose of this study was to assess the diagnostic value of 18F-fluorodeoxyglucose positron emission tomography/computed tomography (FDG-PET/CT) for detecting the lymph node (LN) metastasis of gastric cancer. Materials and Methods: 119 patients (M : F=89 : 30; mean age: 64) with gastric cancer were referred for preoperative FDG-PET/CT scanning and spiral enhanced abdominal pelvic CT from June 2006 to July 2008, and these were the subjects of our study. All the patients underwent curative radical gastrectomy and lymph node dissection. A final diagnosis was made for all the patients by the histology of the surgical specimens. Results: Both PET/CT and enhanced CT showed similar sensitivity for detecting regional lymph node metastasis (32.6% vs 39.5%, respectively). PET/CT was more accurate than enhanced CT for detecting regional lymph node metastasis (67.2% vs 63.0%, respectively), and PET/CT showed better specificity (86.8% vs 76.3, respectively) and a better positive predictive value (PPV) (58.3% vs 48.6%, respectively). PET/CT showed better specificity (98.0% vs 88.2%, respectively) and accuracy (79.4% vs 73.9%, respectively) than enhanced CT for detecting early gastric cancer. PET/CT showed better specificity (64.0% vs 52.0%, respectively), a better PPV (60.9% vs 57.1%), a better negative predictive value (NPV) (48.5% vs 46.4%, respectively) and better accuracy (53.6% vs 51.8%, respectively) than enhanced CT for detecting advanced gastric cancer. Conclusion: FDG-PET/CT is more usefulness than enhanced CT for making the preoperative diagnosis of regional LN metastases from gastric cancers.

• International Journal of CAD/CAM
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• v.6 no.1
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• pp.81-87
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• 2006

This paper describes a method for extracting surfaces from multi-material CT (Computed Tomography) data. Most contouring methods such as Marching Cubes algorithm assume that CT data are composed of only two materials. Some extended methods such as [3, 6] can extract surfaces from the multi-material (non-manifold) implicit representation. However, these methods are not directly applicable to CT data that are composed of three or more materials. There are two major problems that arise from fundamentals of CT. The first problem is that we have to use n(n-1)/2 threshold values for CT data contains n materials and select appropriately one threshold value for each boundary area. The second is that we cannot reconstruct only from CT data in which area three or more materials are adjacent each other. In this paper, we propose a method to solve the problems by using image analysis and demonstrate the effectiveness of the method with application examples construct polygon models from CT data of machine parts.

• Journal of radiological science and technology
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• v.40 no.2
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• pp.245-251
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• 2017

This study measured the exposure dose during abdominal-pelvic CT exam which occupies 70% of CT exam and tried to propose a protocol for optimized exposure dose in abdomen and pelvis without affecting the imagery interpretation. The study scanned abdomen-pelvis using the current clinical scan method, the 120 kVp, auto exposure control(AEC), as 1 phase. As for the newly proposed 2 phase scan method, the study divided into 1 phase abdomen exam and 2 phase pelvis exam and each conducted tube voltage 120 kVp, AEC for abdomen exam, and fixed tube current method in 120 kVp, 100, 150, 200, 250, 300, 350, 400 mA for pelvis exam. The exposure dose value was compared using $CTDI_{VOL}$, DLP value measured during scan, and average value of CT attenuation coefficient, noise, SNR from each scan image were obtained to evaluate the image. As for the result, scanning of 2 phase showed significant difference compared to 1 phase. In $CTDI_{VOL}$ value, the 2 phase showed 26% decrease in abdomen, 1.8~59.5% decrease in pelvis for 100~250 mA, 12.7%~30% increase in pelvis for 300~400 mA. Also, DLP value showed 53% decrease in abdomen and 41~81% decrease in pelvis when scanned by 2 phase compared to 1 phase, but it was not statistically significant. As for the SNR, when scanning 2 phase close to heart, scanning 1 phase close to pelvis, scanning and scanning 1 phase at upper and lower abdomen, it was higher when scanning 2 phase for 200~250 mA. Also, the CT number and noise was overall similar, but the noise was high close to pelvis. However, when scanning 2 phase for 250 mA close to pelvis, the noise value came out similar to 1 phase, and did not show statistically significant difference. It seems when separating pelvis to scan in 250 mA rather than 400 mA in 1 phase as before, it is expected to have reduced effect of exposure dose without difference in the quality of image. Thus, for patients who often get abdominal-pelvic CT exam, fertile women or children, this study proposes 2 phase exam for smaller exposure dose with same image quality.

• Archives of Plastic Surgery
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• v.35 no.5
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• pp.495-500
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• 2008

Purpose: Adequate tissue oxygenation is considered as an essential factor for wound healing. In the non-diabetic population, an uncompromised macrocirculation generally leads to adequate tissue oxygenation. On the contrary, the macrocirculation in diabetic patients may not correlate with tissue oxygenation because of structural changes in the capillary basement membrane. Nevertheless, many medical professionals in Korea rely on macrocirculation evaluation when predicting wound healing potential of the diabetic ulcers. The purpose of this study is to compare reliability of two common macrocirculation assessment methods, Doppler probing and CT angiography, on tissue oxygenation in diabetic foot patients. Methods: Doppler and CT angiography scores were given according to the patency of the anterior and posterior tibial arteries. Tissue oxygenation was measured by transcutaneous partial oxygen tension($TcpO_2$). Doppler and CT angiography scores were statistically analyzed against $TcpO_2$ values. Sixty-eight diabetic foot ulcer patients were included in this study. Results: The test was carried out on Doppler score and $TcpO_2$ variables displayed a p-value of 0.0202, and concluded that the two variables were statistically dependent. The test used to determine for linear trends between Doppler scores and $TcpO_2$ variables displayed a p-value of 0.0149, displaying statistical linear trend between the two variables. On the contrary, the tests between CT angiography scores and $TcpO_2$ variables showed p-values of 0.1242 and 0.6590, that means no correlation between CT angiography and $TcpO_2$ scores. Conclusion: Doppler probing is more reliable than CT angiography in predicting tissue oxygenation of diabetic foot ulcers.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.3
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• pp.1584-1589
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• 2014

This study analyzed CT values of radiolucent and radiopaque materials by energy region after selecting radiolucent and radiopaque materials at random using GE's DECT((Dual Energy Com-puted Tomography) at S University Hospital located in Gyeonggi-province from July through August in 2013. Besides, it drew out the most analogous energy region to the value of 120kVp CT, which is applied to existing SECT(Single Energy Computed Tomography), by utilizing the analysis method of CT values and tried to find out the most useful and appropriate materials when contrast was applied within visible area in clinical application. As a result, there was little decrease of CT value after 90KeV in the case of materials with low density and high moisture content such as normal saline, methyl-cellulose and gels used in ultra-sonic waves test; energy does not influence much on materials with extremely low or high density such as air and contrast medium; methyl-cellulose and gels used in ultra-sonic waves test are considered to be the most useful materials for clinical applications.