• The Korean Journal of Nuclear Medicine Technology
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• v.22 no.1
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• pp.35-42
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• 2018

Purpose Standardized uptake value(SUV) has been widely used as a quantitative metric of uptake in PET/CT for diagnosis of malignant tumors and evaluation of tumor therapy response. However, the SUV depends on various factor including PET/CT scanner specifications and reconstruction parameter. The purpose of this study is to validate a EQ PET to evaluate SUV across different PET/CT systems. Materials and Methods First, NEMA IEC body phantom data were used to calculate the EQ filter for OSEM3D with PSF and TOF reconstruction from three different PET/CT systems in order to obtain EARL compliant recovery coefficients of each spheres. The Biograph true point 40 PET/CT images were reconstructed with a OSEM3D+PSF reconstruction, images of the Biograph mCT 40 and Biograph mCT 64 PET/CT scanners were reconstructed with a OSEM3D+PSF, OSEM3D+TOF, OSEM3D+PSF+TOF. Post reconstructions, the proprietary EQ filter was applied to the reconstruction data. Recovery coefficient can be estimated by ratio of measured to true activity concentration for spheres of different volume and coefficient variability(CV) value of RC for each sphere was compared. For clinical study, we compared SUVmax applying different reconstruction algorithms in FDG PET images of 61 patients with lung cancer using Biograph mCT 40 PET/CT scanner. Results For the phantom studied, the mean values of CV for OSEM3D, OSEM3D+PSF, OSEM3D+TOF and OSEM3D+PSF+TOF reconstructions were 0.05, 0.04, 0.04 and 0.03 respectively for RC. Application of the proprietary EQ filter, the mean values of CV for OSEM3D, OSEM3D+PSF, OSEM3D+TOF and OSEM3D+PSF+TOF reconstructions were 0.04, 0.03, 0.03 and 0.02 respectively for RC. Clinical study, there were no statistical significance of the difference applying EQ PET on SUVmax of 61 patients FDG PET image. (p=1.000) Conclusion This study indicates that CV values of RC in phantom were decreased after applying EQ PET for different PET/CT system and The EQ PET reduced reconstruction dependent variation in SUVs for 61 lung cancer patients, Therefore, EQ PET will be expected to provide accurate quantification when the patient is scanned on different PET/CT system.

• Childhood Kidney Diseases
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• v.16 no.1
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• pp.38-45
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• 2012

Purpose: The incidence of community-acquired urinary tract infection (UTI) due to extended-spectrum ${\beta}$-lactamase producing $Escherichia$ $coli$ (ESBL(+) $E.$ $coli$) has increased worldwide. ESBL causes resistance to various types of the newer ${\beta}$-lactam antibiotics, including the expanded spectrum cephalosporins and monobactams. We aimed to investigate the severity of UTI and associated genitourinary malformations in children with febrile UTI caused by ESBL(+) $E.$ $coli$. Methods: We retrospectively reviewed the medical records of 290 patients diagnosed as febrile UTI caused by $E.$ $coli$ between January 2008 and October 2010 at Korea University Medical center. We classified the patients into two groups with ESBL(+) and ESBL(-) $E.$ $coli$ group according to the sensitivity of urine culture. Fever duration, admission period, white blood cell (WBC) counts and C-reactive protein (CRP) in peripheral blood, the presence of hydronephrosis, cortical defects, vesicoureteral reflux (VUR) and renal scar were compared between the two groups. Results: Patients with ESBL(+) $E.$ $coli$ were 32, and those with ESBL(-) $E.$ $coli$ were 258. If we excluded those tested with a sterile urine bag, patients with ESBL(+) $E.$ $coli$ were 22, and those with ESBL(-) $E.$ $coli$ were 212. Whether the results of sterile urine bag tests were included or not, there was no significant difference in all parameters between the two groups statistically. Conclusion: Our data shows that ESBL(+) $E.$ $coli$ may not be related to the severity of UTI and associated genitourinary malformations.

• Journal of Chest Surgery
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• v.32 no.5
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• pp.413-421
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• 1999

Background: Ischemia reperfusion injury is known to contribute to the major causes of the early graft failure in lung transplantation. Triiodothyronine (T3) has been suggested to ameliorate ischemia reperfusion injury from both in vivo and in vitro experiments of various organs. Prospecting its beneficial effect for pulmonary allograft preservation, we made a new solution by adding T3 into the extracellular type dextran solution. Material and Method: Twelve adult mongrel dogs underwent left lung allotransplantation. Six donor dogs were flushed with the new solution(Group 1, n=6), and the remaining six were flushed with Euro-Collins solution to serve as controls(Group 2, n=6). Allografts were stored in each preservation solution for 20 hours at 4$^{\circ}C$. Left single lung transplantations were performed. The right pulmonary artery and the right main bronchus were clamped at 15 minutes after the reperfusion and maintained throughout the experiment to evaluate the transplanted left lung function. Result: Arterial carbon dioxide tension was better in group 1 than in group 2 throughout the experiment period and the difference was statistically significant at 2 hours after reperfusion(28.0${\pm}$3.0 mmHg and 53.1${\pm}$17.4 mmHg, p<0.05). The differences of arterial oxygen partial pressure, peak airway pressure and pulmonary vascular resistance showed no statistical significance. The malondialdehyde(MDA) level, measured from tissue obtained at 120 minutes after reperfusion showed no statistically significant difference. The tissue wet/dry ratio of group 1(649${\pm}$27 %) was significantly lower than that of group 2(686${\pm}$71 %, p<0.05). The microscopic examination revealed varying degrees of injury represented mainly by findings such as perivascular neutrophil infiltration, capillary hemorrhage and interstitial congestion. These findings were less severe in group 1 than those in group 2. Conclusion: The new solution demonstrated superior allograft preservation after 20 hour ischemia compared to Euro-Collins solution in canine single left lung transplantation model, these results suggest that T3 might be a promising agent for pulmonary allograft preservation.

• Childhood Kidney Diseases
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• v.13 no.1
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• pp.40-48
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• 2009

Purpose : This study was performed to identify factors related to the resolution of primary vesicoureteral reflux (VUR) in infants. Methods : We reviewed 183 infants (M : F=149 : 34) diagnosed as urinary tract infection (UTI) between February 2002 and July 2007 at Sanggye Paik Hospital. The diagnosis of UTI was made by culture from a urine specimen obtained by suprapubic puncture (n=97), catheterization (n=83), or collection bag method (n=3, twice positive culture of same organism). All of the infants were performed renal ultrasonography, DMSA scan and voiding cystourethrography (VCUG) study. Follow-up imaging consisted of contrast VCUG or direct isotope VCUG at interval of 1 year. We evaluated the relationship of clinical and laboratory finding, radiologic finding in infants with VUR. Results : Among 51 VUR patients, 18 infants had grade I-II, 12 infants had grade III and the other 21 patients had grade IV-V. Abnormal findings including hydronephrosis on renal ultrasonography were not correlated with severity of VUR. However, the incidence of renal defect in the first DMSA scan showed a tendency of direct correlation with severity of VUR in female patients only (P<0.001). There was significant difference of resolution rate in three VUR groups (grade I-II, III, IV-V) in male patients only (P=0.025). Resolution rate was higher for male patients with unilateral VUR than bilateral (P<0.001). But unilaterality had not any affect on VUR resolution in female VUR patients (P=0.786). Resolution rate was higher for VUR patients without renal scar than VUR patients with renal scar (P<0.001). Conclusion : According to our findings, grade of VUR, laterality and renal scar are the factors that contribute to resolution of primary VUR in male and female infants differently.

• Journal of Chest Surgery
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• v.38 no.9 s.254
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• pp.616-621
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• 2005

Background: In the resection of lung cancer, pneumonectomy occupied $20 {\~}35\%$ of all resections, and significantly high operative mortality is reported in right pneumonectomy ($10{\~}25\%$). The aim of this study is to identify the characteristics of morbidity, operative mortality and factors affecting operative mortality after pneumonectomy. Material and Method: This study recruited the database which performed pneumonectomy for lung cancer in Korea Cancer Center Hospital from Aug 1987 to Apr 2002. Result: Total of 386 pneumonectomies were peformed in that period. Sidedness were left in 238, right in 148; and the procedures were standard resection in 207, and extended resection in 179. Morbidity occurred in 115 cases ($29.8\%$, 115/386). Mortality occurred in 12 cases ($3.1\%$, 12 in 386). This mortality rate was similar to that of lobectomy ($2.1\%$, 13 in 613) during the same period. Morbidity consisted of 42 hoarseness, 17 (9) pneumonia and ARDS, 8 empyema, 5 (1) broncho-pleural fistula, 5 reoperation for bleeding, 5 (1) arrhythmia, 1 (1) pulmonary edema, and 25 others (The number in the parenthesis is the number of mortality case for that morbidity). Several factors affecting the operative mortality were evaluated. At first, extended procedure ($3.3\%$, 6 in 179) affected the operative mortality similar to the standard procedure ($2.9\%$, 6 in 207)(p=0.812). Second, the rate of operative mortality in an elderly group over 60 years ($5.5\%$, 10 in 182) was significantly higher than the younger group under 60 years ($1\%$, 2 in 204)(p=0.016). Third, sidedness of resection affects to operative mortality. Right pneumonectomy ($6.8\%$, 10 in 148) showed higher operative mortality than that of left pneumonectomy ($0.8\%$, 2 in 238)(p=0.002). The group over 60 years showed higher incidence of respiratory morbidity ($11.0\%$, 20 in 182) than that of the group under 60 years ($3.4\%$, 7 in 204)(p=0.005). Right pneumonectomy also showed significantly higher incidence ($11.5\%$, 17 in 148) than that of left pneumonectomy ($4.2\%$, 10 in 238)(p=0.008). Conclusion: Age and sidedness of pneumonectomy were the risk factors of operative mortality and respiratory complications, Therefore, careful selection of patients and more attention perioperatively were demanded in right pneumonectomy. However, because the operative mortality is acceptable, pneumonectomy could be done safely if the pneumonectomy is necessary for curative resection of lung cancer.

• Journal of KIISE:Computer Systems and Theory
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• v.33 no.3
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• pp.166-177
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• 2006

The cache size tends to grow in the embedded processor as technology scales to smaller transistors and lower supply voltages. However, larger cache size demands more energy. Accordingly, the ratio of the cache energy consumption to the total processor energy is growing. Many cache energy schemes have been proposed for reducing the cache energy consumption. However, these previous schemes are concerned with one side for reducing the cache energy consumption, dynamic cache energy only, or static cache energy only. In this paper, we propose a hybrid scheme for reducing dynamic and static cache energy, simultaneously. for this hybrid scheme, we adopt two existing techniques to reduce static cache energy consumption, drowsy cache technique, and to reduce dynamic cache energy consumption, way-prediction technique. Additionally, we propose a early wake-up technique based on program counter to reduce penalty caused by applying drowsy cache technique. We focus on level 1 data cache. The hybrid scheme can reduce static and dynamic cache energy consumption simultaneously, furthermore our early wake-up scheme can reduce extra program execution cycles caused by applying the hybrid scheme.

• Clinical and Experimental Pediatrics
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• v.51 no.6
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• pp.576-583
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• 2008

Purpose : The identification of specific behaviors conducive to overeating or inactivity is the cornerstone of obesity management. The Committee on Nutrition of the Korean Pediatric Society developed parent and self-reporting questionnaires about eating behavior and physical activity in 2006. The aim of this study was to evaluate the usefulness of the questionnaires in assessing modifiable lifestyle factors related to obesity. Methods : A retrospective chart review was performed for 177 children (6-11 years old) and 134 adolescents (12-16 years old) from 10 hospitals between May 2006 and January 2007 who had completed parent or self-reporting questionnaires. Cases were divided into normal and overweight groups at or above the age-gender-specific 85th percentile based on 2007 Korean national growth charts. Results : Compared to children, the adolescents tended to have a significantly more sedentary lifestvle and inappropriate dietary behaviors significantly (P<.05). Overweight mothers were significantly associated with overweight children and adolescents (P<.05). Being overweight was significantly associated with a family history of adult diseases for children and adolescents (P<.05). Inappropriate eating behaviors (strong appetite, eating fast, eating until they were full, binge eating, favoring greasy foods) were associated with being overweight in children and adolescents. Sedentary activity such as TV viewing and using a computer were significantly associated with overweight in children and adolescents (P<.05). Conclusion : Intervention to modify obesity-related lifestyle factors is needed before adolescence. These questionnaires are useful in identifying modifiable lifestyle factors and in individual counseling for overweight children and adolescents in pediatric clinics.

• Journal of radiological science and technology
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• v.36 no.4
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• pp.313-318
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• 2013

Positron emission tomography/computed tomography (PET/CT) imaging with fluorodeoxyglucose (FDG) have been used as a powerful fusion modality in nuclear medicine not only for detecting cancer but also for staging and therapy monitoring. Nevertheless, there are various causes of FDG uptake in normal and/or benign tissues. The purpose of present study was to investigate whether additional delayed imaging can improve the diagnosis to differentiate the rates of FDG uptake at axillary lymph nodes (ALN) between malignant and benign in breast cancer patients. 180 PET/CT images were obtained for 27 patients with ALN uptake. The patients who had radiotherapy and chemotherapy were excluded from the study. $^{18}F$-FDG PET/CT scan at 50 min (early phase) and 90 min (delayed phase) after $^{18}F$-FDG injection were included in this retrospective study. The staging of cancers was confirmed by final clinical according to radiologic follow-up and pathologic findings. The standardized uptake value (SUV) of ALN was measured at the Syngo Acquisition Workplace by Siemens. The 27 patients included 18 malignant and 9 ALN benign groups and the 18 malignant groups were classified into the 3 groups according to number of metastatic ALN in each patient. ALNs were categorized less than or equal 3 as N1, between 4 to 9 as N2 and more than 10 as N3 group. Results are expressed as the mean${\pm}$standard deviation (S.D.) and statistically analyzed by SPSS. As a result, Retention index (RI-SUV max) in metastasis was significantly higher than that in non-metastasis about 5 fold increased. On the other hand, RI-SUV max in N group tended to decrease gradually from N1 to N3. However, we could not prove significance statistically in malignant group with ANOVA. As a consequence, RI-SUV max was good indicator for differentiating ALN positive group from node negative group in breast cancer patients. These results show that dual-time-point scan appears to be useful in distinguishing malignant from benign.

• Neonatal Medicine
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• v.16 no.1
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• pp.36-46
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• 2009

Purpose: To evaluate the neonatal statistics on a national basis, data for birth characteristics and neonatal mortality were collected and analyzed from 57 hospitals in Korea. Methods: Questionnaires were distributed to determine the characteristics of neonatal births and mortality rates in 57 hospitals in Korea during 2007. We analyzed the characteristics of all inborn births and hospitalized neonates in the neonatal care units (NICUs) and compared the results with published Korean data from 1996 and 2002. Results: A total of 40,433 inborn live births were reported from the 57 hospitals during 2007. Pre-term, term, and post-term births comprised 24.2%, 75.6%, and 0.2% of the neonates, respectively. Low birth weight infants (LBWIs), very low birth weight infants (VLBWIs), and extremely low birth weight infants (ELBWIs) made up 22.0%, 4.6%, and 1.7% of the neonates, respectively. A total of 21,957 (collected by gestational period) and 21,356 (collected by birth weight) neonates were hospitalized in the 57 NICUs. Pre-term, term, and post-term neonates comprised 39.8%, 59.8%, and 0.4% of the neonates, respectively. LBWIs, VLBWIs, and ELBWIs made up 37.3%, 9.5%, and 3.3% of the neonates, respectively. Pre-term, term, and post-term neonates had mortality rates of 4.5%, 0.7%, and 3.7%, respectively, while the mortality rates of LBWIs, VLBWIs, and ELBWIs were 4.7%, 15.3%, and 32.2%, respectively. In comparison with prematurity data from 1996 and 2002, LBWIs, and ELBWIs had a marked increase in birth frequency and a decreased mortality rate in Korea during 2007. Conclusion: The number of live births and the survival rate of pre-term neonates, especially VLBWIs and ELBWIs, are increasing. Even though the outcomes of neonatal care are improving, further efforts to manage these premature infants are needed.

• Childhood Kidney Diseases
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• v.9 no.2
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• pp.128-136
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• 2005

Purpose : Urine collection using a sterile adhesive bag for urinalysis has been used commonly in infants and young children. However, this method has had some drawbacks. So, this study was performed to evaluate the usage of disposable diapers as a substitute for the routine urine collection method. Methods : 60 mL of self voided fresh urine was collected from 99 patients. Half of the urine was poured on the disposable diapers which did not contain absorbent gel beads. After 1 hr, we obtained the urine samples(extracted urine) by compressing the wet diapers using a 50 ml syringe. Routine, microscopic and biochemical analyses were performed on the other half of fresh urine and extracted urine. Then we compared each result by correlative analysis. Results : 198 samples from 99 patients were evaluated. The results of routine urinalysis except WBC and biochemical urinalysis showed a significant correlation between the two groups(P<0.05). The relative coefficients of urine SG, pH, glucose, protein, blood and leukocytes between the two groups were 0.964, 0.938, 0.977, 0.956, 0.931 and 0.738, respectively. Those of urinary sodium, potassium, chloride and creatinine were 0.997, 0.998, 0.995 and 0.998, respectively Microscopic examinations showed lower relative coefficients than the other results, 0.740 for RBC and 0.602 for WBC, but these were still significant(P<0.05). Conclusion : The results of the urine analysis with extracted urine from diapers correlates well with that of fresh urine. This new method is very helpful and can be used as an alternative of urine collection, especially for infants and young children. (J Korean Soc Pediatr Nephrol 2005;9:128-136)