• The korean journal of orthodontics
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• v.26 no.1 s.54
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• pp.53-63
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• 1996

In order In analyze the occlusion of TMD patient, 73 casts and post eroanterior cephalometric X-rays of patients showing TMD symptoms at first interview were measured and compared that of 30 non-patients . Horizental overjet, vertical overbite, openbite, crossbite, depth of curve of Spee, midline deviation, facial asymmetry, attrition, and TPI were measured and processed statistically The results could be summarized as follows, 1. TMD group showed the highest prevalence in twenties, teens, and before 9 years old group in order, and more prevalent in female than male. 2. There were no statistically significance between two groups of overjet and overbite measurements, but showed significance of 6 classification of anterior tooth relationship between two groups TMD groups. 3. n group had more anterior openbite than normal group but there were no statistically significance between two groups. 4. Anterior crossbite was more prevalent in normal group brit posterior crossbite was more prevalent in TMD group. 5. TMD group showed deeper curve of Spee and there were statistically significance between two groups. 6. TMD group had more attrition than normal group and there were statistically significance beween two groups. 7 TMD group showed more facial asymmetry than normal group. 8. TPI did not showed statistical significance beween two groups. According to the above results, TMD group showed severe and complex mode of malocclusion and this should be carefully regarded when treatment planning and during the treatment of malocclusion.

• The korean journal of orthodontics
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• v.33 no.3 s.98
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• pp.211-222
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• 2003

The purpose of this study was to determine whether there is an association between disk displacement of the Temporomandibular Joint (TMJ) and dentofacial asymmetry In orthodontic patients. The subjects consisted of 60 female orthodontic patients between the ages of 18 and 38 years (mean age 23.3 years) who had visited the Department of Orthodontics at Seoul National University Dental Hospital from January 2000 to April 2002. On the basis of magnetic resonance imaging (MRI) of their bilateral TMJs, the subjects were divided Into four groups'. bilateral normal group (twenty-one persons); disk displacement of right TMJ group (six persons); disk displacement of left TMJ group (nine persons); and disk displacement of both TMJs group (twenty-four persons) Postero-anterior (PA) cephalograms and diagnostic models which had been taken before orthodontic treatment were measured. In the linear measurements, a line connecting the right and left Latero-Orbitale (Lo) represented the horizontal reference line (H). The vertical reference line (V) was constructed as a line bisecting and running perpendicular to H. One-way analysis of variance (ANOVA) was used to test whether the mean values of measurements between groups were significantly different. In addition, Bonferronil's multiple comparison test was performed at a level of 0.05. The results were as follows; 1 In the diagnostic model analysis, the overjet, nght molar relationship, and left molar relationship were significantly different among the four groups. 2. In the PA cephalometric analysis, differences in the right and left vertical position of the lower first molar and Ag were significantly dissimilar among the four groups. 3. If the disk displacement of TMJ was present on one side, the ipsilateral ramus was shorter, resulting in asymmetry in the vertical position of Ag. This study indicated that dentofacial asymmetry might be related to the disk displacement of TMJ.

• 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.

• Journal of Korean Ophthalmic Optics Society
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• v.12 no.4
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• pp.55-69
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• 2007

The purpose of this study was to perform a clinical test using ez NANOsence II RGP contact lenses for the effects of visual acuity and cornea on subjects with abnormal refraction status. One hundred twenty one adults (twenty nine males, ninety two females, range = 17 to 43, mean = 22.86) were recorded. The subject's history including, the symptoms from previous lens wear, were studied. The subjects were observed, both pre and post lens wear, for any symptoms and signs of change of the eye. The Visual acuity and the binocular status were tested at the far distance using the contact lens. The refraction test was performed on the naked eye using the objective method (Topcon KR-8100, Japan). The Stereopsis test was performed at the near distance after contact lens wear by the Titmus fly (Stereo Optical Co., U.S.A) and TNO (TECH, The netherlands). The contrast sensitivity diagnosis was performed at 1m distance after contact lens wear by the contrast sensitivity chart (pelli-Robertson, USA). The corneal topography was analyzed on the naked eye after lens wear by ORB scan (Bausch Lomb, U.S.A.). The ultra structure of surface on the contact lens was observed using SEM (JMS-5800, Japan). The chemical component's of the contact lens was analyzed by EDS program. The results of this study were as follows: 1. The longer of contact lens wear period, The subjects have acquired the most improved visual function. 2. Subjects had experienced few side effects wearing the contact lenses. 3. The lenses were easy to use by the subjects. 4. The longer of contact lens wear period, the power of cornea had more decrease. but the base curve of cornea had more increase and corneal astigmatism was decrease (p<0.01). Also, the thickness of corneal center was few decrease. 5. Longer periods of using the contact lens showed stereopsis and contrast sensitivity at more normal values. 6 The corneal topographical after lens wear showed most subjects with similar morphology for different wear periods. 7. The surface ultrastructure of the new and used contact lens was the similar fine shape. 8. The chemical component's of in the new and used contact appeared to have similar results. In conclusion, this study showed that the surface ultrastructure and chemical component's of the new and used contact lens are similar. In addition, the subjects had improved the quality of vision and few experienced any side effects during long periods of contact lens wear. Also they have decrease of corneal astigmatism during the long period of lens wear. Our test has showed that the chemical composition and fine structure of contact lens have related to the visual function on contact lens wearer. In this paper, we suggested that ez NANOsence II RGP contact lenses had a moderate effect for correcting vision of abnormal refraction eye.

• Korean Security Journal
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• no.21
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• pp.75-94
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• 2009

Since mechanical security systems are mostly composed of electronic, information and communication devices, they have effects in the aspects of overall social environment and crime-oriented environment. Also, the importance is increasing for wireless recognition of RFID and tracing function, which will be usefully utilized in controlling the incomings and outgoings of people/vehicles or allowance, surveillance and control. This is resulting from the increase in the care for the elderly according to the overall social environment, namely, the aging society, and the number of women entering, as well as the increase in the number of heinous crimes. The purpose of this study is to examine the theoretical considerations on ubiquitous sensor network and present a direction for securities companies for their development by focusing on the technological and application areas. To present strategies of response to a new environment for security companies, First, a diversification strategy is needed for security companies. The survival of only high level of security companies in accordance with the principle of liberal market competition will bring forth qualitative growth and competitiveness of security market. Second, active promotion by security companies is needed. It is no exaggeration to say that we are living in the modern society in the sea of advertisements and propaganda. The promotional activities that emphasize the areas of activity or importance of security need to be actively carried out using the mass media to change the aware of people regarding security companies, and they need to come up with a plan to simultaneously carry out the promotional activities that emphasize the public aspect of security by well utilizing the recent trend that the activities of security agents are being used as a topic in movies or TV dramas. Third, technically complementary establishment of ubiquitous sensor network and electronic tag is needed. Since they are used in mobile electronic tag services such as U-Home and U-Health Care, they are used throughout our lives by forming electronic tag environment within safe ubiquitous sensor network based on the existing privacy guideline for the support of mobile electronic tag terminal commercialization, reduction in communication and information usage costs, continuous technical development and strengthening of privacy protection, and the system of cooperation of academic-industrial-research needs to be established among the academic world and private research institutes for these parts.

• Journal of radiological science and technology
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• v.29 no.4
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• pp.229-236
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• 2006

Purpose: This study was conducted to search for the type of technical error in DEXA(dual-energy X-ray absorptiometry) and the effect of error to measurement of BMD. Materials and Methods: The changes of BMD($g/cm^2$, T-score) by patients information(Age, Weight, Height, Manopause age) input error and Confirming ROI error were investigated. Using spine phantom, we canned 10 times by age(5, 10), weight(10, 20 kg), height(5, 10 cm), manopause age(5, 10) increase & decrease respectively. Scanning region(L-spine, femur, Forearm) of 10 patients was calculated by changing ROI respectively. Analysis of difference for mean(precision 1%) were carried out. Results: The error of patient information(Age, Weight, Height, Manopause age) was not changed differently. In confirming ROI, the BMD and T-score of L-spine involving T-12 was decreased to $0.063\;g/cm^2$, 0.3 and involving L-5 increased to $0.077\;g/cm^2$, 0.5. In narrowing 1 cm of vertical line of ROI, the BMD and T-score decreased to $0.006\;g/cm^2$, 0.1 and in 2 cm, $0.021\;g/cm^2$, 0.15, each. In hip ROI, Upper and left shift(0.5 cm) of line was not influenced BMD and T-score. In 0.5 cm lower shift(lesser trochanter below), the BMD and T-score increased $0.031\;g/cm^2$, 0.3 and in 1 cm $0.094\;g/cm^2$, 0.65, each. In forearm ROI, the BMD and T-score decreased $0.042\;g/cm^2$, 0.9 involving 1 cm lower wrist. And expanding 1 cm of vertical line, the BMD and T-score decreased $0.008\;g/cm^2$, 0.1 and in 2 cm, $0.021\;g/cm^2$, 0.3, each. The L-spine, hip, forearm ROI error was changed differently. Conclusion: There are so many kinds of technical error in BMD processing. Errors according to age, weight, height, manopause age did not influent to $BMD(g/cm^2)$ and T-score. There are mean differences BMD and T-score in confirming ROI. For the precision exam, in L-spine processing, L1-4 have to confirmed without shift of ROI vertical line. In hip processing, the ROI have to included greater trochanter, femur head and lesser trochanter. In forearm processing, the ROI have to included wrist, radius and ulnar.

• Journal of radiological science and technology
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• v.35 no.4
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• pp.345-352
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• 2012

As the breast cancer rate is increasing fast in Korean women, people pay more attention to mammography and number of mammography have been increasing dramatically over the last few years. Mammography is the only means to diagnose breast cancer early, but harms caused by radiation exposure shouldn't be overlooked. Therefore, it is important to calculate the radiation dose being absorbed into the breast tissue during the process of mammography for a protective measure against radiation exposure. Because it is impossible to directly measure the radiation dose being absorbed into the human body, statistical calculation methods are commonly used, and most of them are supposed to simulate the interaction between radiation and matter by describing the human body internal structure with anthropomorphic phantoms. However, a simulation using Geant4 Code of Monte Carlo Method, which is well-known as most accurate in calculating the absorbed dose inside the human body, helps calculate exact dose by recreating the anatomical human body structure as it is through the DICOM file of CT. To calculate the absorbed dose in the breast tissue, therefore, this study carried out a simulation using Geant4 Code, and by using the DICOM converted file provided by Geant4, this study changed the human body structure expressed on the CT image data into geometry needed for this simulation. Besides, this study attempted to verify if the dose calculation of Geant4 interlocking with the DICOM file is useful, by comparing the calculated dose provided by this simulation and the measured dose provided by the PTW ion chamber. As a result, under the condition of 28kVp/190mAs, the Difference(%) between the measured dose and the calculated dose was found to be 0.08 %~0.33 %, and at 28 kVp/70 mAs, the Difference(%) of dose was 0.01 %~0.16 %, both of which showed results within 2%, the effective difference range. Therefore, this study found out that calculation of the absorbed dose using Geant4 Simulation is useful in measuring the absorbed dose in the breast tissue for mammography.

• Journal of radiological science and technology
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• v.32 no.3
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• pp.299-306
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• 2009

Purpose : To compare radiation dose for coronary CT angiography (CTA) obtained with 6 examination protocols such as a retrospectively ECG gated helical scan, a prospectively ECG gated sequential scan, low kVp technique, and cardiac dose modulation technique. Materials and Methods : Coronary CTA was performed by using 6 current clinical protocols to evaluate effective dose and organ dose in primary beam area with anthropomorphic female phantom and glass dosimetric system in 64 channel multi-detector CT. After acquiring topograms of frontal and lateral projection with 80 kVp and 10 mA, main coronary scan was done with 0.35 sec tube rotation time, 40 mm collimation ($0.625\;mm{\times}64\;ea$), small scan field of view (32 cm diameter), 105 mm scan length. Heart beat rate of phantom was maintained 60 bpm in ECG gating. In constant mAs technique 120 kVp, 600 mA was used, and 100 kVp for low kVp technique. In a retrospectively ECG gated helical CT technique 0.22 pitch was used, peak mA (600 mA) was adopted in range of $40{\sim}80%$ of R-R interval and 120mA(80% reduction) in others with cardiac dose modulation. And 210 mAs was used without cardiac dose modulation. In a prospectively ECG gated sequential CT technique data were acquired at 75% R-R interval (middle diastolic phase in cardiac cycle), and 120 msec additional padding of the tube-on time was used. For effective dose calculation region specific conversion factor of dose length product in thorax was used, which was recommended by EUR 16262. Results : The mean effective dose for conventional coronary CTA without cardiac dose modulation in a retrospectively ECG gated helical scan was 17.8 mSv, and mean organ dose of heart was 103.8 mGy. With low kVp and cardiac dose modulation the mean effective dose showed 54.5% reduction, and heart dose showed 52.3% reduction, compared with that of conventional coronary CTA. And at the sequential scan(SnapShot pulse mode) under prospective ECG gating the mean effective dose was 4.9 mSv, this represents an 72.5% reduction compared with that of conventional coronary CTA. And heart dose was 33.8 mGy, this represents 67.4% reduction. In the sequential scan technique under prospective ECG gating with low kVp the mean effective dose was 3.0 mSv, this represents an 83.2% reduction compared with that of conventional coronary CTA. And heart dose was 17.7 mGy, this represents an 82.9% reduction. Conclusion : In coronary CTA at retrospectively ECG gated helical scan, cardiac dose modulation technique using low kVp reduced dose to 50% above compared with the conventional helical scan. And the prospectively ECG gated sequential scan offers substantially reduced dose compared with the traditional retrospectively ECG gated helical scan.

• Journal of radiological science and technology
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• v.40 no.1
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• pp.109-120
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• 2017

In order to examine how Radiological Technologists perceive the oriental doctor's use of Medical Imaging Equipment, surveys were conducted for the members of the Korean Radiological Technologists Association. The total number of respondents were 515 and 481, with 34 insincere responses removed caused of nonvalidated answer. The results of the analysis are as follows. Although there were no statistical significance in the difference in perception by location of residence, work place, and educational background, respondents with higher education showed a tendency to agree on the use of comprehensive medical imaging equipment, but tended to oppose the use of special medical imaging equipment. Differences in perception by gender showed a greater negative perception toward the oriental doctor's use of medical imaging equipment by women than men. In particular, women showed more negative tendency for oriental doctor's use of special medical imaging equipment such as MRI, CT, and ultrasound equipment compared to men, and this was statistically significant. The difference in perception by age showed that the oriental doctor's use of medical imaging equipment was negative in the 20~30s, neutral in the 40~50s, and positive in the 60s, which were statistically significant. The difference in perception by work experience showed that the longer the work experience was, the more positive it was toward oriental doctor's use of medical imaging equipment. Specifically, the most favorable tendency was found with work experience of more than 30 years, which was statistically significant. The results of this study revealed the Radiological Technologists' perceptions on the oriental doctor's use of Medical Imaging Equipment and this can contribute to the direction of public health promotion in the future.

• Korean Journal of Community Nutrition
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• v.7 no.1
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• pp.121-129
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• 2002

Osteoporosis, the typical metabolic bone disease of the elderly, is characterized by a reduction in bone mineral density (BMD) and increased fracture risk. Genetic and environmental factors are known to play a key role in bone metabolism, and diet is also considered to be one of the important factors. The purpose of the present study was to investigate the relationship among the factors affecting BMD, including stature, body weight, age, time period since onset of menopause, and biochemical markers of bone turnover in postmenopausal women. Seventy-eight postmenopausal women who visited health promotion center for health examinations volunteered to participate in this study and they were divided into two groups according to the time period since onset of menopause : women with a time period since onset of menopause of less than 5 years (Group 1) and women with a time period since onset of menopause of 5 years or more (Group 2). The demographic characteristics and dietary intake were surveyed using a questionnaire. BMDs of the lumbar spine and femoral neck of subjects were measured by dual energy X-ray absorptiometry. Serum levels of 25-hydroxy-vitamin D and parathyroid hormone (PTH), known to be indicators of bone related hormone status, were anlyzed. Serum samples were measured for calcium, phosphorus, alkaline phosphatase, and osteocalcin as bone formation indicators, and urine was analysed for deoxypyridinoline, creatinine, calcium, and sodium as bone resorption indicators. The results are as follow : The mean BMDs of the lumbar spin and femoral neck were $1.02 \pm 0.02 g/cm^2 and 0.81 \pm 0.02 g/cm^2 respectively, and the BMD level of Group 2 was significantly lower than tat of Group 1 (p<0.01, p<0.05, respectively). The mean daily intake of energy was 1838 $\pm$ 55 kcal. When nutrient intake was compared with the recommended dietary allowances (RDA) of the subjects, only calcium, vitamin A and riboflavin intake showed means lower than the RDA. The nutrient intake did not show any significant differences between Group 1 and 2 Serum and urine levels of biochemical markers of bone turnover did not show any significant differences between Group 1 and 2, and all were within the normal range. However, the PTH and deoxypyridinoline levels showed a tendency to be higher, and the osteocalcin level to be lower in Group 2 than in Group 1. Although age and years after menopause (YAM) showed negative correlations with lumbar spine bone mineral density (LBMD) (r= -0.38, p<0.001, and r= -0.26, p< 0.05, respectively), no correlation was found with femoral neck bone mineral density (NBMD). While height, body weight and body mass index (BMI) showed a positive correlation with LBMD (r= 0.32, p<0.001, r= 0.38, p<0.001, r= 0.22, p= 0.05, respectively), only body weight and BMI showed a positive correlation with NBMD (r= 0.30, p<0.01, and r= 0.27, p<0.05, respectivley). There was no significant corealtion between BMDs and the nutrient intake of subjects, except in the case of carbohydrates (r= 0.22, p<0.05). Also, serum and urine levels of bone turnover markers showed no significant correlation with nutrient intake. On the other hand, serum osteocalcin had a positive correlation with vitamin C intake (r= 0.22, p= 0.05), and urine deoxypyridinolin showed a negative correlation with niacin intake (r= -0.22, p= 0.05). Urinary na was negatively correlated with protein intake(r= -0.23, p= 0.05). The results suggested that it is difficult to prevent the decrease in bone mass among postmenopausal women eating the usual Korean diet. However, the BMDs of the lumbar spine and femoral neck were positively related to body weight ad BMI in postmenopausal women. Therefore, this study confirmed that one of the most effective ways to minimize bone loss in postmenopausal women would be to maintain an adequate body weight with balanced nutrient intake and activity in the pre-and postmenopausal periods.