• The Korean Journal of Nuclear Medicine Technology
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• v.15 no.2
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• pp.83-87
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• 2011

Purpose: Recently in diagnostics area PET/CT is using a variety of areas including oncology, as well as in cardiology, neurology, etc. While increasing in the importance of PET/CT, there are various researches in the image quality related to reconstruction method. We compared and tested Iterative 2D Reconstruction Method with True X Reconstruction method by Siemens through phantom experiment, so we can see increasing of clinical usefulness of PET/CT. Materials and Methods: We measured contrast ratio and FWHM due to evaluating images on dose and experiment using Biograph 40 True Point PET/CT (Siemens, Germany). Getting a result of contrast ratio and FWHM, we used NEMA IEC PET body phantom (Data Spectrum Corp.) and capillary tube. We used the current TrueX and the previous Iterative 2D algorithm for all images which have 10 minutes long. Also, a clinical suitability of parameter for Iterative 2D and a recommended parameter by Siemens for True X are applied to the experiment. Results: We tested FWHM using capillary tube. As a result, TrueX was less than Iterative 2D. Also, the differences of FWHM get bigger in low dose. On the other hand, we tested contrasts ratio using NEMA IEC PET body phantom. As a result, TrueX was better aspect than Iterative 2D. However, there was no difference in dose. Conclusion: In this experiment, TrueX get higher results of contrast ratio and spatial resolution than Itertive 2D through experiment. Also, in the reconstruction result through TrueX, TrueX had better aspect of resolution than Iterative 2D in low dose. However, contrast ratio had no specific difference. In other words, TrueX reconstruction method in PET/CT had higher clinical value in use because TrueX can reduce exposure of patient and had a better quality of screen.

• Investigative Magnetic Resonance Imaging
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• v.4 no.1
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• pp.27-33
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• 2000

Purpose: To determine the electronic spin relaxation times, $T_{le}$, of three commercially available Gd-chelated MR contrast agents, Gd-DTPA, Gd-DTPA-BMA and Gd-DOTA, using Electron Paramagnetic Resonance(EPR) technique. Material and Methods: The paramagnetic MR contrast agents, Gd-DTFA(Magnevist) , Gd-DTFA-BMA(OMNISCAN) and Gd-DOTA(Dotarem), were used for this study, The EPR spectra of these contrast agents, which were prepared 2:1 methanol/water solution, were obtained at low temperatures, from $-160^{\circ}C~20^{\circ}C$. The glassy-state EPR spectra for these contrast agents were then fitted by the simulation spectra generated with different zero-field splitting (ZFS) parameters by a computer simulation program 'GEN', which generates the EPR powder spectrum using a given ZFS in $3{\times}3$ tensor. Finally, the spin relaxation times of the contrast agents were then determined from the $T_{2e}$, D, and E values of the best simulation spectra using the McLachlan's theory of average relaxation rate. Results: The electronic transverse spin relaxation times, $T_{2e}'s$, of Gd-DTPA, Gd-DTPA-BMA and Gd-DOTA were 0.113ns, 0.147ns and 1.81ns respectively. The g-values were 1.9737, 1.9735 and 1.9830 and the electronic spin relaxation times, $T_{1e}'s$, were 18.70ns, 33.40ns and $1.66{\mu}s$, respectively. Conclusion: The results of these studies reconfirm that the paramagnetic MR contrast agents with larger ZFS parameters should have shorter $T_{1e}'s$. Among three contrast agents used for this study, Gd-DOTA chelated with cyclic ligand structure shows better electronic property then the others with linear structure. Thus, it is concluded that the exact determination of ZFS parameters is the important factor in evaluating relaxation enhancement effect of the agents and in developing new contrast agents.

• Journal of Korean Ophthalmic Optics Society
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• v.19 no.1
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• pp.87-92
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• 2014

Purpose: Comparison with contrast sensitivity between binocular and monocular of 20s adult was measured by spatial frequency 3.0, 6.0, 12.0 and 18.0 cpd and compares difference between monocular and binocular and difference between male and female. Methods: Topcon CV-3000 Phoroptor was used for full correction of 99 ophthalmic optics students and contrast sensitivity were measured by using Vector Vision CSV-1000E at 2.5 m in photopic condition (100 $cd/m^2$). Results: Photopic condition at 2.5 m, average contrast sensitivity of entire subject was 52.54, 80.40, 36.79 and 13.56 with right eye and 52.33, 81.29, 41.73 and 14.22 with left eye in 3, 6, 12 and 18 cpd. For both eye 65.46, 113.69, 52.04 and 19.44 were measured. The contrast sensitivity of male was 58.22, 83.52, 37.89 and 13.82 with right eye and 56.03, 46.68 and 15.67 with left eye in spatial frequency of 3, 6, 12 and 18 cpd. Both eyes were measured to 70.89, 120.96, 56.56 and 19.89. The contrast sensitivity of female was 46.50, 77.09, 35.61 and 13.28 with left eye and 48.40, 70.43, 36.47 and 12.68 with left eye in spatial frequency of 3, 6, 12, 18 cpd. Both eyes were 59.68, 105.97, 47.23 and 18.95. Conclusions: Contrast sensitivity value of binocular shows higher than monocular to both male and female. Contrast sensitivity of difference between male and female were statistically remarkably higher to male in right eye 3 cpd, left eye 6 cpd, 12 cpd and both eye 3 cpd. In other frequency, there was no statistical significance but male shows higher.

• Nuclear Medicine and Molecular Imaging
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• v.40 no.3
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• pp.169-176
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• 2006

Purpose: According to the development of CT scanner in PET/CT system, the role of CT unit as a diagnostic tool has been more important. To improve the diagnostic ability of CT scanner, it is a key aspect that CT scanning has to be performed with high dose energy and intravenous (IV) contrast. So we investigated the effect of IV contrast media on the maximum SUV (maxSUV) of normal tissues and pathologic lesions using PET/CT scanner with high dose CT scanning. Materials & Methods: The study enrolled 13 patients who required PET/CT evaluation. At first, the patients were performed whole body non-contrast CT (NCCT-120 kVp, 130 mAs) scan. Then contrast enhanced CT (CECT) scan was performed immediately. Finally PET scan was followed. The PET omission data were reconstructed twice, once with the NCCT and again with the CECT. We measured the maxSUV of 10 different body regions that were considered as normal in ail patients. Also pathologic lesions were investigated. Results: There were not seen focal artifacts in PET images based on CT with IV contrast agent. Firstly, 130 normal regions in 13 patients were evaluated. The maxSUV was significantly different between two PET images (p<0.00)). The maxSUV was $1.1{\pm}0.5$ in PET images with CECT-corrected attenuation and $1.0{\pm}0.5$ in PET images with NCCI-corrected attenuation. The limit of agreement was $0.1{\pm}0.3$ in Bland-Altman analysis. Especially there were significant differences in 6 of 10 regions, apex and base of the right lung, ascending aorta, segment 6 & segment 8 of the liver and spleen (p<0.05). Secondly, 39 pathologic lesions were evaluated. The maxSUV was significantly different between two PET images (p<0.001). The maxSUV was $4.7{\pm}2.0$ in PET images with CECT-corrected attenuation and $4.4{\pm}2.0$ in PET images with NCCT-corrected attenuation. The limit of agreement was $0.4{\pm}0.8$ in Bland-Altman analysis. Conclusion: Although there were increases of maxSUVs in the PET images based on CT with IV contrast agent, it was very narrow in the range of limit of agreement. So there was no significant effect to clinical interpretation for PET images that were corrected attenuation with high dose CT using IV contrast.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.38 no.2
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• pp.179-190
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• 2001

In this proposed study, observing and analyzing contrast enhanced abdominal CT images, we segmented the liver automatically. We computed the ratio of each gray value from the estimated gray value range. With the average value of mesh image, we distinguished the liver from the noise parts. We divided the region based on immersion simulation. The threshold value is determined from the mesh image which is generated from each gray value portion of the liver and is used in dividing the liver to the noise region. To get the outline of the liver, we generated template image which represents the lump of the liver, and subtracted it from the binary image. With the results we use the proposed algorithm using 8-connectivity instead of the present opening algorithm, to reduce the processing time. We computed the volume from the segmented organ size and presented a clinical demonstration with the animal experiment

• Journal of Food and Nutrition Research
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• v.9 no.7
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• pp.350-356
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• 2021

This study was conducted in Cheonan of central region in South Korea to identify alfalfa cultivars with superior adaptability to the local environment. To evaluate the growth characteristics, productivity, and feed value of 26 alfalfa cultivars, field experiments were conducted with a randomized block design (three replicates) for three years. Among the 26 alfalfa cultivars, "Natsuwakaba" showed the highest dry matter yield (DMY, 37,083 kg/ha), with a significantly higher three-year average than that of other cultivars. Furthermore, the three-year-average DMYs of "Alfalfa short" (31,044 kg/ha) and "Radar II Brand" (31,163 kg/ha) were significantly higher than those of other cultivars. In addition, differences among the feed values of the alfalfa cultivars were relatively less significant than the differences among their productivity, as the feed value was less influenced by the cultivation conditions and cultivars. Although "Jin Huang Hou" and "Certified organic" exhibited the highest feed values when cultivated in central region in South Korea, "Natsuwakaba" outperformed all cultivars in both productivity and feed value. The acid and neutral detergent fiber (ADF and NDF, respectively) contents of "Jin Huang Hou" (38.9% and 47.26%, respectively) were significantly lower than those of other cultivars. In contrast, the ADF and NDF contents of "Burgaltai" (46.52% and 55.56%, respectively) implied poor feed value upon cultivation in South Korea. The crude protein (CP) content in the alfalfa cultivars ranged from 14.95% to 19.44% during early flowering, and the highest CP content was observed for "Certified organic." The in-vitro digestibility of alfalfa was approximately 70% for all cultivars during early flowering, indicating good digestibility of most of the cultivars.

• Korean Journal of Radiology
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• v.25 no.1
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• pp.43-54
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• 2024

Objective: To evaluate the added value of diffusion-weighted imaging (DWI)-based quantitative parameters to distinguish uterine sarcomas from atypical leiomyomas on preoperative magnetic resonance imaging (MRI). Materials and Methods: A total of 138 patients (age, 43.7 ± 10.3 years) with uterine sarcoma (n = 44) and atypical leiomyoma (n = 94) were retrospectively collected from four institutions. The cohort was randomly divided into training (84/138, 60.0%) and validation (54/138, 40.0%) sets. Two independent readers evaluated six qualitative MRI features and two DWI-based quantitative parameters for each index tumor. Multivariable logistic regression was used to identify the relevant qualitative MRI features. Diagnostic classifiers based on qualitative MRI features alone and in combination with DWI-based quantitative parameters were developed using a logistic regression algorithm. The diagnostic performance of the classifiers was evaluated using a cross-table analysis and calculation of the area under the receiver operating characteristic curve (AUC). Results: Mean apparent diffusion coefficient value of uterine sarcoma was lower than that of atypical leiomyoma (mean ± standard deviation, 0.94 ± 0.30 10^-3 mm²/s vs. 1.23 ± 0.25 10^-3 mm²/s; P < 0.001), and the relative contrast ratio was higher in the uterine sarcoma (8.16 ± 2.94 vs. 4.19 ± 2.66; P < 0.001). Selected qualitative MRI features included ill-defined margin (adjusted odds ratio [aOR], 17.9; 95% confidence interval [CI], 1.41-503, P = 0.040), intratumoral hemorrhage (aOR, 27.3; 95% CI, 3.74-596, P = 0.006), and absence of T2 dark area (aOR, 83.5; 95% CI, 12.4-1916, P < 0.001). The classifier that combined qualitative MRI features and DWI-based quantitative parameters showed significantly better performance than without DWI-based parameters in the validation set (AUC, 0.92 vs. 0.78; P < 0.001). Conclusion: The addition of DWI-based quantitative parameters to qualitative MRI features improved the diagnostic performance of the logistic regression classifier in differentiating uterine sarcomas from atypical leiomyomas on preoperative MRI.

• Journal of Distribution Science
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• v.13 no.9
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• pp.59-70
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• 2015

Purpose - This study aims to suggest strategies for Korean enterprises advancing into the Vietnam bakery market by analyzing the effects of perceived values on brand preference and purchase intention among Korean and Vietnamese consumers. Research design, data, and methodology - The perceived value model designed includes functional (price, quality), emotional, and social values. The survey collected data from 500 consumers in Seoul (Korea) and HoChiMinh (Vietnam). The SPSS 18.0 package was used for analysis. Results - First, among Vietnamese consumers, perceived value had a positive (+) effect on global brand preference in the order of functional value of quality, social value, and the functional value of price. However, from an ethnocentric trend and brand image origin, emotional value had a negative effect on global brand preference. In contrast, among Korean consumers, perceived value had a positive (+) effect on global brand preference in the order of functional value of quality, the functional value of price, and the social value. However, emotional value had no effect on global brand preference. Second, for both Korean and Vietnamese consumers, perceived value had a significant positive effect on purchase intention. Third, unlike the Korean consumer, for the Vietnamese consumer, global brand preference had a significant effect on purchase intention. Conclusions - The study implies the following. First, the Vietnamese bakery market has a high proportion of middle-aged customers in their 40s (64%). In terms of monthly income, there was a large proportion (40%) of high-income earners (over $325). Therefore, bakery consumption can be seen as concentrated among middle-aged and high-income consumers. Based on this, bakery strategies should include efforts to increase purchase prices as well as ways to attract local consumers (large cities). Second, unlike Korean consumers, among Vietnamese consumers, the resistance to a global brand based on emotional value (the ethnocentric tendency and brand image origin) can be seen as relatively low. Thus, in the case of the Vietnam bakery market, to increase a global brand's preference, the company should develop a differentiated strategy so that Vietnamese consumers can recognize it better, focusing on product quality, good service quality, and price in the local environment and on social value for social development. Third, in the case of the Vietnamese customer, we found that social value exerts the greatest influence on purchase intention. Therefore, a brand that engenders an image of building the local Vietnamese community can achieve a higher social value and influence purchase intention. In addition, although Vietnamese consumers have ethnocentric tendencies in terms of products, we found that if it is a preferred global brand then there are intentions to purchase. Fourth, in the case of Vietnam, if the preference for global brands is formed, consumer awareness may be connected to purchase intention. Therefore, global brands operating in Vietnam should pay attention to how to improve consumer preferences for global brands in order to increase purchase intention.

• Journal of Radiation Protection and Research
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• v.35 no.4
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• pp.135-141
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• 2010

Purpose : The patients who visited this department for pulmonary disease and need CT scans for Follow-up to observe change of CT value, evaluation of image quality and decrease of radiation dose as change of kVp. Subjects and Methods : Subjects were the patients of 20 persons visited this department for pulmonary disease and Somatom Sensation 16(Semens, Enlarge, Germany) was used. Measurement of CT value as change of kVp was done by setting up ROI diameter of 1cm at the height of thyroid, aortic arch, right pulmonary artery in arterial phase image using 100 kVp, measuring 3 times, and recorded the average. CT value of phantom was measured by scanning phantoms which means contrast media diluted by normal saline by various ratio with tube voltage of 80 kVp, 100 kVp, 120 kVp, 140 kVp and recorded the average of 3 CT values of center of phantom image. In analysing radiation dose, CTDIVOL values of the latest arterial phase image of 120 kVp and as this research set that of 100 kVp were analyzed comparatively. 2 observers graded quality of chest images by 5 degrees (Unacceptable, Suboptimal, Adequate, Good, Excellent). Results : CT value of chest image increased at 100 kVp by 14.06%~27.26% in each ROI than 120 kVp. CT value of phantom increased as tube voltage lowered at various concentration of contrast media. CTDIVOL decreased at 100 kVp(5.00 mGy) by 36% than 120 kVp(7.80 mGy) in radiation dose analysis. here were 0 Unacceptable, 1 Suboptimal, 3 Adequate, 10 Good, 6 Excellent in totally 20 persons. Conclusion : Chest CT scanning with low kilo-voltage for patients who need CT scan repeatedly can bring images valuable for diagnose, and decrease radiation dose against patients.

• Korean Journal of Veterinary Research
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• v.15 no.2
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• pp.161-176
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• 1975

In order to evaluate the epizootiological influence of high-land on cattle feeding, routine hematological observation, with additional examinations of feces and general clinical condition, was conducted comparing the high-land cows resident at altitude of 800 to 1,200 meters in Daegwanryeong to the low-land cows resident at altitudes of less than 100 meters in Samcheok and Gangneung. The high-land cows were divided into 3 groups such as group A, B and C, consisting of 15, 16 and 20 adult cows respectively, and among the 3 groups only group C was exposed to abrupt high-land cold before observation. The low-land cows, that is group D, were consisted of 25 adult cows. The results obtained in the survey were summarized as follows: 1. Number of erythrocytes, concentration of hemoglobin and packed cell volume were remarkably higher (p<0.01) in all of 3 groups (group A, B and C) of high-land cows than trios of low-land cows (group D). These higher values in high-land cows were ascribable to the better feeding and hygienic management, and lesser infestation of small-type Piroplasma (Theileria) and internal parasites in contrast with the low-land cows. 2. Remarkably higher value of mean corpuscular volume (p<0.01) and a tendency to lower value of mean corpuscular hemoglobin concentration were noted in group D in contrast with group A, B and C. The reason was attributed to the higher infestation (p<0.01) of smalltype piroplasma in low-land cows in contrast with high-land cows. 3. It was noticiable that even though lesser infestation of small type Piroplama in the highland cows was shown, a natural case of clinical small-type-piroplasmosis was found in high-land group B as well as a case in the low-land group D. The blood Pattern showed characteristic macrocytic-hypochromic-anemia with increased reticulocytes in both two cases (Table 7). 4. In the observation of leukocytic series, marked increase of eosinophils in group D was seen in accordance with heavy infestation of gastrointestinal nematodes, and increased neutrophils with higher appearance of nonlobulated form and eosinopenia in group C only was observed suggesting the leukocytic response to the cold exposure in high-land. 5. Mean values of thrombocytes in group A,B,C and D were 48.4, 40.7, 42.7 and $32.3{\times}10^4/mm^3$ respcetively, and no statistically significant differences were observed.