• Journal of the Korean Society of Radiology
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• v.11 no.7
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• pp.547-553
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• 2017

In the current medical field, lead is widely used as a radiation shield. However, the lead weight is very heavy, so wearing protective clothing such as apron is difficult to wear for long periods of time and there is a problem with the danger of lethal toxicity in humans. Recently, many studies have been conducted to develop substitute materials of lead to resolve these problems. As a substitute materials for lead, barium(Ba) and iodine(I) have excellent shielding ability. But, It has characteristics emitting characteristic X-rays from the energy area near 30 keV. For patients or radiation workers, shielding materials is often made into contact with the human body. Therefore, the characteristic X-rays generated by the shielding material are directly exposured in the human body, which increases the risk of increasing radiation absorbed dose. In this study, we have developed the FLUKA transport code, one of the most suitable elements of radiation transport codes, to remove the characteristic X-rays generated by barium or iodine. We have verified the reliability of the shielding fraction of the structure of the structure shielding by comparing with the MCPDX simulations conducted as a prior study. Using the MCNPX and FLUKA, the double layer shielding structures with the various thickness combination consisting of barium sulphate ($BaSO_4$) and bismuth oxide($Bi_2O_3$) are designed. The accuracy of the type shown in IEC 61331-1 was geometrically identical to the simulation. In addition, the transmission spectrum and absorbed dose of the shielding material for the successive x-rays of 120 kVp spectra were compared with lead. In results, $0.3mm-BaSO_4/0.3mm-Bi_2O_3$ and $0.1mm-BaSO_4/0.5mm-Bi_2O_3$ structures have been absorbed in both 33 keV and 37 keV characteristic X-rays. In addition, for high-energy X-rays greater than 90 keV, the shielding efficiency was shown close to lead. Also, the transport code of the FLUKA's photon transport code was showed cut-off on low-energy X-rays(below 33keV) and is limited to computerized X-rays of the low-energy X-rays. But, In high-energy areas above 40 keV, the relative error with MCNPX was found to be highly reliable within 6 %.

• Pediatric Infection and Vaccine
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• v.16 no.2
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• pp.162-166
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• 2009

Purpose : Urinary tract infection (UTI) is one of the most common bacterial infectious disease in childhood. Renal scarring is an important complication of UTIs. Known risk factors for renal scarring are younger age, anatomic defects, delayed treatment, and causative pathogens other than Escherichia coli. The aim of this study was to compare the characteristics of clinical and laboratory features of UTI with E. coli to those with non-E. coli in infants. Methods : We reviewed the medical records of 1,120 infants under 12 months of age who had been admitted for UTIs between January 1998 and December 2007. All patients who were diagnosed with UTIs were divided into two groups (E. coli and non-E. coli UTIs). Results : Three hundred twenty-four of 1,120 cases met the inclusion criteria. The number of E. coli and non-E. coli UTIs was 273 (84.3%) and 51 (15.7%), respectively. As compared to the non-E. coli UTI group, the E. coli UTI group was younger (3.59 vs. 4.47 months, P =0.008), a longer duration of pyuria (3.96 vs. 3.06 days, P =0.01), higher peripheral white blood cell counts (13.89 vs. $12.13{\times}10^3/mm^3$, P =0.043), and lower rates of high degree (III-V) vesico-ureteral reflux (P =0.005). Conclusion : UTIs with E. coli might have more severe clinical features and a lower prevalence of high grade vesicoureteral reflux than UTIs with non-E. coli. However, no difference was noted in the clinical response to antibiotic therapy between the two groups.

• Pediatric Gastroenterology, Hepatology & Nutrition
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• v.9 no.2
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• pp.193-199
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• 2006

Purpose: The proper diagnosis of Meckel's diverticulum (MD) is difficult and delayed because of the variety of clinical manifestations. We reviewed clinical characteristics of symptomatic MD to facilitate early detection. Methods: We analyzed retrospectively the clinical manifestations, diagnostic tools, histopathological findings, and operative findings in 58 patients with symptomatic MD. Results: The male to female ratio was 2.8 : 1. The most common symptom of MD was bleeding. Others symptoms included: vomiting, abdominal pain, irritability, abdominal distension and fever in the order of frequency. The clinical manifestations of symptomatic MD were lower gastrointestinal bleeding, intestinal obstruction, perforation, diverticulitis and hemoperitoneum, in the order of frequency. The causes of intestinal obstruction were intussusception, internal hernia, band, volvulus, invagination, in the order of frequency. Seventy five percent of patient with MD were diagnosed prior to 5 years of age. The most frequently used diagnostic tool was the Meckel's scan. The diverticulum was located 2 cm to 120 cm proximal to the ileocecal valve. The length of the diverticulum ranged from 1 cm to 10 cm and 94% were less than 5 cm. The most common ectopic tissue found in the MD was gastric mucosa. Ileal resection was more frequently performed than diverticulectomy. Conclusion: In cases of unexplained gastrointestinal bleeding, obstruction and repeated intussusception, the meckel's scan, ultrasound and computed tomography shoud be considered to rule out MD, and if clinically necessary, an exploratory laparotomy when needed.

• The Journal of the Korean bone and joint tumor society
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• v.6 no.2
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• pp.61-68
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• 2000

Purpose : We examined the patients to evaluate the radiologic findings of solitary plasmacytoma of the bone. Materials and Methods : We retrospectively reviewed radiologic findings of 9 cases with solitary plasmacytoma of the bone (SPB) for recent 5 years, but 2 cases were not included this study due to an abnormal finding of bone marrow and another 2 cases were not included due to an abnormal manifestations of computed tomography (n=1) and MRI (n=1). Results : Among 5 cases, 4 cases had an osteolytic bone destruction and 1 case had an osteosclerotic bone destruction on the plain radiograph. Computed tomography and MRI showed more informations about trabeculated bone destruction and the soft-tissue extension of the lesion comparing to plain radiographs. The MRI finding of SPB in 4 cases showed a relatively high signal intensity on T1-weighted image and intermediate signal intensity on T2-weighted image, on which the signal intensity of the lesion is slightly higher than that of the muscle. One case had an extensive soft-tissue involvement and multiple necrosis, which presented iso to low signal intensity on T1-weighted image and high heterogeneous signal intensity on T2-weighted image. The Gadolinium-enhanced T1-weighted images of 5 cases showed diffusely strong enhancement of the lesion except on the necrosis areas. Conclusion : Computed tomography and MRI may present some characteristics of SPB and demonstrate another foci of plasma cell infiltrates, so these can be helpful for the diagnosis and treatment of SPB.

• Pediatric Infection and Vaccine
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• v.10 no.1
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• pp.81-86
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• 2003

Purpose : Streptococcus pneumoniae remains a leading cause of meningitis, sepsis, pneumonia, and otitis media in children worldwide. Emergence of drug-resistant organism has substantially complicated the therapy of these infections. This study was conducted to determine the clinical features and changing patterns of antibiotic-resistant rates of Streptococcus pneumoniae. Methods : We have retrospectively examined 306 cases of culture proven patients who were admitted to the Department of Pediatrics, Severance hospital, from the year 1991 to year 2000. The type of culture specimen used, presence of penicillin resistance, characteristics according to various presenting diseases and their prevailing year were also examined. Results : The mean age of cases was 7.9 year and the ratio of male to female was 1.6 : 1. The main age group of pneumococcal infection was under 2 years(42%). Systemic infections associated with pneumococci were sepsis(19.3%) and meningitis(9.5%), while local infections presented as pneumonia(29.2%), otitis media(19.3%), exudative tonsillitis(13.3%), and sinusitis(9.2%) in the order of frequency. Seasonal variation was seen in the incidence of pneumococcal infection: high incidence of infection was seen in Spring(Mar.~Apr; 32%), while the incidence was low during summer(Aug.~Sep.; 6%). Penicillin-resistant rate of pneumococci was steadily on the increase since the year 1991(65%) to year 2000(84%). Conclusion : Antibiotic-resistant pneumococci increased during the past decade. For effective prevention of pneumococcal infections, national survey of pneumococcal infections and expanded use of pneumococcal vaccination would be needed.

• The Korean Journal of Nuclear Medicine
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• v.30 no.4
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• pp.560-569
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• 1996

Background and Purpose : Standardized uptake value(SUV) has been used as a quantitative index for differentiating benign and malignant tumors with F-18-FDG PET In this study, we produced whole body parametric images of SUV(WBPIS) by body weight normalization, and validated the values by comparison with SUV's calculated with regional scans. Subjects and Methods : Whole body scans were followed by regional scans sequentially on 23 patients. In whole body study, transmission and emission scans were acquired for 2 minutes and 6 minutes for each bed position, respectively. In regional study, transmission and emission scans were acquired for 20 minutes. Measured and segmented/ smoothed attenuation correction were applied using these 2 min transmission scans in whole body studies. The effects of attenuation correction on SUVs were evaluated quantitatively using F-18 filled cylindrical phantom. The mean and peak SUVs obtained from WBPIS were compared with SUVs of the regional scans. Results : In phantom studies, with any method of attenuation correction using regional or whole body studies of phantom, SUVs were nearly consistent. In whole body scan, SUV obtained using measured attenuation correction method was a little higher than SUV of regional scan. SUV obtained using segmented/smoothed attenuation correction method was a little lower. In patient studies, WBPIS using segmented/smoothed attenuation correction method was much smoother and more readable. SUVs of WBPIS obtained with both methods of attenuation correction were well correlated with SUVs of regional scans(r=0.9). SUVs of WBPIS with measured attenuation correction method were 5% lower than SUVs of regional scans. SUVs of WBPIS with segmented/smoothed attenuation correction method were 10% lower than SUVs of regional scans. The differences of SUVs of WBPIS by the two attenuation correction methods were relatively small compared with the possible differences derived from biological characteristics of tumors. Conclusion : We concluded that WBPIS could be useful in the quantification of tumor as well as in localization of whole body lesions, which were often outside the field of view in regional scan. WBPIS made using segmented/smoothed attenuation correction method could be used in clinical routines and SUVs from attenuation corrected F-18-FDG PET could be used interchangeably with SUVs of regional studies.

• Journal of the korean academy of Pediatric Dentistry
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• v.37 no.2
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• pp.193-201
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• 2010

Early childhood caries (ECC) is a comprehensive terminology that includes nursing bottle caries and rampant dental caries occurred in infants and children. In previous studies, ECC was thought to affect body growth of children negatively. The purpose of this study was to evaluate the effect of ECC on body growth of children in respect of their chronologic age and degree of dental caries. Height and body weight were used as means for physical growth measurements. Children, who visited the pediatric department of Yonsei University Dental Hospital, received oral and physical examinations, and they were divided into the control and ECC groups. Then, each group was subdivided according to their age and gender. Two-sample T test was used to compare the mean height and body weight of the control and ECC groups, and Likelihood Ratio Chi-square test was used to compare their growth percentile distribution. When the mean height and weight were compared, there was a common tendency observed even though statistical significance was not found in all cases. Before the age of 3-4, the mean height and weight tended to be greater in the ECC groups compared to the control groups, whereas after the age of 3-4, the mean height and weight of the ECC group tended to be less compared to the control group. In addition, in groups with age equal or greater than 3-4, which presented significant difference in height and body weight, the percentage of children showing less than 3 percentile growth was greater in the ECC group than the control group. These results imply the negative effects of the ECC on physical growth of the infants and children, and its effects on physical growth may present different characteristics according to chronologic age of the patients.

• Korean Journal of Psychosomatic Medicine
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• v.26 no.1
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• pp.35-43
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• 2018

Objectives : Effects of multiple trauma are complex and extend beyond core PTSD symptoms. However, few psychological instruments for trauma assessment address this issue of symptom complexity. The Trauma Symptom Checklist-40 (TSC-40) is a self-report scale that assesses wide range of symptoms associated with childhood or adult traumatic experience. The purpose of the present study was to evaluate the validity of the Korean Version of the TSC-40 in a sample of psychiatric outpatients. Methods : Data of 367 treatment-seeking patients with DSM-IV diagnoses were obtained from an outpatient department of psychiatric unit at a university hospital. The diagnoses were anxiety disorder, posttraumatic stress disorder, depressive disorder, adjustment disorder and others. Included in the psychometric data were the TSC-40, the Life events checklist, the Impact of Event Scale-Revised, the Zung's Self-report Depression Scale, and the Zung's Self-report Anxiety Scale. Cronbach's ${\alpha}$ for internal consistency were calculated. Convergent and concurrent validity was approached with correlation between the TSC-40 and other scales (PTSD, anxiety and depression). Results : Exploratory factor analysis of the Korean Version of TSC-40 extracted seven-factor structure accounted for 59.55% of total variance that was contextually similar to a six-factor structure and five-factor structure of the original English version. The Korean Version of TSC-40 demonstrated a high level of internal consistency. (Cronbach's ${\alpha}=0.94$) and good concurrent and convergent validity with another PTSD scale and anxiety and depression scales. Conclusions : Excellent construct validity of The Korean Version of TSC-40 was proved in this study. And subtle difference in the factor structure may reflect the cultural issues and the sample characteristics such as heterogeneous clinical population (including non-trauma related disorders) and outpatient status. Overall, this study demonstrated that the Korean version of TSC-40 is psychometrically sound and can be used for Korean clinical population.

• Journal of Yeungnam Medical Science
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• v.12 no.2
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• pp.226-236
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• 1995

We studied to evaluate CT characteristics of bronchogenic cysts. We retrospectively evaluated CT of 11 patients with pathologically proved bronchogenic cyst. Precontrast and postcontrast CT scan was performed in all. We analyzed CT with viewpoints of location, size, attenuation on pre- and postcontrast scan, and calcification. Three of 11 bronchogenic cysts were intrapulmonary in location and eight were located in the mediastinum. Two of 3 intrapulmonary bronchogenic cysts were located in the right lower lobe, and the remaining one was left lower lobe. Intrapulmonary bronchogenic cysts ranged from 6cm to 12cm in diameter (average, 9.7 cm). On CT, intrapulmonary bronchogenic cysts appeared as thin-wall air cyst, homogenous water attenuation and soft tissue attenuation with air bubble respectively. Mediastinal bronchogenic cysts were located in posterior mediastinum(n=5), superior mediastinum(n=2), middle mediastinum(n=1) respectively. These cysts ranged in size from 3cm to 8cm in diameter (average, 5.0 cm). On CT, five showed homogenous water attenuation, two soft tissue attenuation similar to that of muscle, one air-fluid level. Calcification or contrast enhancement was not detected in any cases. On operative findings, all of intrapulmonary bronchogenic cysts contained dirty pus-like material and all of mediastinal bronchogenic cysts contained whitish or yellowish mucus material. Bronchogenic cysts showed homogenous water density in many cases, homogenous soft tissue density, air-fluid level and air-filled cyst. The constellation of CT findings may be helpful in the diagnosis and differentiation of bronchogenic cyst.

• Korean Journal of Psychosomatic Medicine
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• v.24 no.1
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• pp.74-82
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• 2016

Objectives : Suicide attempters have impaired decision making and are at high risk of reattempt. Therefore it is important to refer them to psychiatric treatment. Especially, People with medical comorbidity are at higher risk of suicidal attempt and mortality. The aim of this study was to investigate the characteristics of suicidal attempters and to analyze the influence of the medical comorbidity on decision to receive psychiatric treatment after visit to an emergency department. Methods : One hundred and thirty two patients, who visited the emergency room of a general hospital in Gyeonggi-do between January, 2012 and December, 2012 were enrolled as the subjects of this study. After reviewing each subject's medical records retrospectively, demographic and clinical factors were analyzed. Results : Regardless of the engagement type, either via admission or outpatient clinic, the determinant factors of psychiatric treatment engagement were psychiatric diagnosis, employment status, previous psychiatric treatment history, and previous attempt history. Comparison of severity of medical comorbidity(Charlson Comorbidity Index) showed that suicide attempters who received psychiatric treatment via admission or refused the treatment tended to have higher level of medical comorbidity than who received psychiatric treatment via outpatient department. Conclusions : Our findings showed that medical comorbidity of suicide attempters affected the decision to accept psychiatric treatment. All psychiatrists should evaluate the presence and the severity of medical comorbidity of the suicide attempters and consider implementing more intervention for the medically ill attempters who are willing to discharge against advice.