• The Korean Journal of Nuclear Medicine Technology
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• v.21 no.2
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• pp.74-79
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• 2017

Purpose Proton therapy can deliver an optimal dose to tumor while reducing unnecessary dose to normal tissue as compared the conventional photon therapy. As proton beams are irradiated into tissue, various positron emitters are produced via nuclear fragmentation reactions. These positron emitters could be used for the dose verification by using PET. However, the short half-life of the radioisotopes makes it hard to obtain the enough amounts of events. The aim of this study is to investigate the effect of off-line PET imaging scan time on the PET image quality. Materials and Methods The various diameters of spheres (D=37, 28, 22 mm) filled with distilled water were inserted in a 2001 IEC body phantom. Then proton beams (100 MU) were irradiated into the center of the each sphere using the wobbling technique with the gantry angle of $0^{\circ}$. The modulation widths of the spread out bragg peak were 16.4, 14.7 and 9.3 cm for the spheres of 37, 28 and 22 mm in diameters respectively. After 5 min of the proton irradiation, the PET images of the IEC body phantom were obtained for 50 min. The PET images with different time courses (0-10 min, 11-20 min, 21-30 min, 31-40 min and 41-50 min) were obtained by dividing the frame with a duration of 10 min. In order to evaluate the off-line PET image quality with the different time courses, the contrast-to-noise ratio (CNR) of the PET image calculated for each sphere. Results The CNRs of the sphere (D=37 mm) were 0.43, 0.42, 0.40, 0.31 and 0.21 for the time courses of 0-10 min, 11-20 min, 21-30 min, 31-40 min and 41-50 min respectively. The CNRs of the sphere (D=28 mm) were 0.36, 0.32, 0.27, 0.19 and 0.09 for the time courses of 0-10 min, 11-20 min, 21-30 min, 31-40 min and 41-50 min respectively. The CNR of 37 mm sphere was decreased rapidly after 30 min of the proton irradiation. In case of the spheres of 28 mm and 22 mm, the CNR was decreased drastically after 20 min of the irradiation. Conclusion The off-line PET imaging time is an important factor for the monitoring of the proton therapy. In case of the lesion diameter of 22 mm, the off-line PET image should be obtained within 25 min after the proton irradiation. When it comes to small size of tumor, the long PET imaging time will be beneficial for the proton therapy treatment monitoring.

• Pediatric Gastroenterology, Hepatology & Nutrition
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• v.3 no.1
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• pp.68-74
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• 2000

Purpose: This study was to investigate the clinical manifestations of FTT in children. Methods: From March 1997 to July 1999, clinical observations were made on patients with FTT who had visited to Samsung Medical Center. Detailed histories and through physical examinations were taken, and when suspected organic FTT, basic laboratory studies were done. Results: Upon the review of medical records, we investigated the clinical manifestations of 74 children, aged 1 month and 13 year 1 month. The causes of FTT were composed of either physiologic (47.8%) or pathologic (52.2%) ones. Among the physiologic FTT, were there familial short stature (FSS, 14.5%), intrauterine growth retardation (IUGR, 14.5%), constitutional growth delay (CGD, 11.6%), idiosyncrasy and prematurity. Among pathologic causes, neurologic disorders (20%) are the most common causes of FTT, and then follow by GI (13.4%), allergic and infectious disorders in decreasing order. The data showed that average caloric intake in patients with FTT was 76,2% of recommended amount. FTT patients with CGD, IUGR, and idiosyncrasy had tendency to take small foods. The FTT children with prematurity, IUGR and pathologic FTT, were short and thin for their ages. However FTT children with CGD and FSS had tendency to be thin with relatively normal heights for their ages, in comparison with those of the children with prematurity, IUGR and pathologic FTT. Conclusion: The diagnosis of FTT was easily obtained with simple and through medical history, physical examination, and minimal laboratory tests. In this study, organic FTT was more prevalent than physiologic one. This results indicate that early intervention is mandatory, because children may develop significant long-term sequelae from nutritional deficiency.

• Pediatric Gastroenterology, Hepatology & Nutrition
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• v.14 no.1
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• pp.52-58
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• 2011

Purpose: Mecnoium obstruction in very low birth weight infants (VLBWI), which delays enteral feeding and is one of the major causes of bowel obstruction, can be diagnosed and treated with hyperosmolar water-soluble contrast enema. The purpose of this study was to observe the clinical findings of meconium obstruction, the improvement of small bowel obstruction after contrast enema, and the complications related to the enema. Methods: Hypersolmolar water-soluble contrast enemas were performed in 14 VLBWIs with meconium obstruction. Clinical findings, radiologic findings, feeding intolerance, effectiveness, and complications of enemas were observed. Also, clinical findings related to meconium obstruction were compared with 18 VLBWIs without meconium obstruction. Results: 1) Fourteen VLBWIs with meconium obstruction had significantly lower 5 minutes Apgar scores than 18 VLBWIs without meconium obstruction (p<0.05). Moreover, the day of last meconium passing, and the day of the first trial and full enteral feeding were delayed significantly. 2) A total of 18 enemas were performed in the 14 infants. The contrast medium passed the ileocecal valve and reached the terminal ileus in 12 enemas. Of the 12 enemas, 11 were successful, but 1 infant underwent an ileotomy, even though the contrast medium reached the terminal ileum. 3) Intestinal obstruction was not relieved in three of five infants, in whom the contrast medium failed to pass the ileocecal valve. Obstruction was relieved after repeated enemas in which the contrast medium reached the terminal ileum. 4) No complications associated with water-soluble contrast enemas were observed. Conclusion: Hyperosmolar water-soluble contrast enema is considered to be safe and therapeutic for meconium obstruction in VLBWIs.

• Pediatric Gastroenterology, Hepatology & Nutrition
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• v.11 no.2
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• pp.110-115
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• 2008

Purpose: Intussusceptions are one of the most common causes of intestinal obstruction in infants and young children. Although it is easily treated by non-operative reduction using barium, water or air, this treatment is very stressful for young patients and may cause bowel perforation, peritonitis and shock. In this study, we identified the risk factors associated with the failure of non-operative reduction, to identify a group of children that would benefit from the procedure and those who would not. Methods: We reviewed the medical records of patients with intussusception who were treated at the Korea University Medical Center Ansan hospital from March 1998 to July 2006. Three hundred fourteen children with intussusception were identified. Among them, non-operative reductions were performed in three hundred. Clinical and radiological variables were compared according to the failure or success of the non-operative reduction. Results: Non-operative reductions were successful in 243 (81%) and failed in 57 (19%). The group that had failed procedures had a younger age (12.3${\pm}$17.2 months vs. 18.0${\pm}$15.8 months, p=0.03), longer symptom duration before reduction (33.6${\pm}$29.0 hr vs. 21.5${\pm}$20.3 hr, p<0.01), more vomiting and lethargy (p<0.01), but less abdominal pain and irritability (p<0.01), compared with the group that had a successful procedure. Logistic regression analysis showed that the factors associated with the failure of non-operative reductions were a younger age, less than 6 months of age (odds ratio: 2.5, 95% confidence interval: 1.2~5.2, p=0.01), duration of symptoms, longer than 24 hrs before reduction (odds ratio: 2.1, 95% confidence interval: 1.2~4.2, p=0.03), bloody stool (odds ratio: 4.8, 95% confidence interval: 1.9~12.2, p<0.01), lethargy (odds ratio: 3.4, 95% confidence interval: 1.1~10.4, p=0.04), and abdominal pain or irritability (odds ratio: 0.2, 95% confidence interval: 0.1~0.4, p<0.01). Conclusion: For children with intussusception, an age younger than 6 months, and duration of symptoms more than 24 hrs before reduction, as well as the presence of bloody stools, lethargy and abdominal pain or irritability were variables associated with failure of a non-operative reduction. Knowledge of these variables should be considered in making clinical decisions for therapeutic interventions.

• Pediatric Infection and Vaccine
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• v.5 no.2
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• pp.245-257
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• 1998

Purpose : Although hepatitis B vaccine has been available to general population in Korea since 1983, it was difficult to compare various types of hepatitis B virus(HBV) vaccines primarily due to the differences in vaccination schedule, dosage, test methods and seropositive antibody level. In this study we reviewed the results of previous studies published in Korea, which include antibody positive rates and antibody titers of various vaccines, and examined the immunogenicity of these HBV vaccines. Methods : Studies published in medical journals, university journals concerning antibody positive rates following hepatitis B vaccination were reviewed. Inclusion criteria were those studies in which seroprotective antibody rate of 10mIU/mL or the sample ratio unit of 10 RU were used as the cut-off value and in which the test methods were RIA or ELISA. Exclusion criteria were; 1) unclear or inconsistent vaccine dosage, 2) no record of antibody titers or seroconversion rate, 3) no defined antibody rate or ratio for positive rating and 4) the vaccination schedule other than 0-1-2 months or 0-1-6 months. Results : 23 out of 52 studies were subjected for the review for seroconversion rates. 1) As for the immunogenicity in each age group, the seroconversion rates of Hepaccine(Cheil Jedang) were 85.1% in infants, 83.3% in children and 62.7% in adults, indicating higher rates in infants and children compared to adults(P<0.01). The seroconversion rates of Hepavax(Korea Green Cross) were 84.7%, 81.1% and 90.8%, indicating higher rates in infants and adults compared to children(P<0.01). 2) The seroconversion rate of Hepavax was 85.6% with 0-1-6 mo. schedule, 78.5% with 0-1-2 mo. schedule with a statistically significant difference(P<0.01). 4) There was no difference of seroconversion rates between the two doses of Hepavax, $5{\mu}g$ and $10{\mu}g$ in infants and children. 5) In adults the seroconversion rates were 62.7% with Hepaccine, 90.8% with Hepavax, and 94.8% with Engerix-B(SmithKline Beecham). Conclusion : In Korea, the incidence of chronic hepatitis B is high and changing the schedule in vaccination cannot contribute to the increase of the serocoversion rate. And in order to maximize immunogenicity, more effective vaccines as well as more proper vaccination methods should be used.

• Pediatric Infection and Vaccine
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• v.5 no.2
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• pp.221-229
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• 1998

Purpose : The symptom of urinary tract infection in children is non-specific and systemic compared to that of adults. So the diagnosis of UTI in children can be delayed. If UTI in children is not appropriately managed, it may he resulted in renal failure, hypertension, growth failure in adolescence because there are already documented renal scar or urinary tract abnormality in infection period. Especially upper UTI that involve renal parenchyme may be result in fatal complication. The purpose of this study is analyzing the relationship between acute reactive marker and $^{99m}TC$-DMSA renal scan in upper urinary tract infection. Methods : This study included 56 children admitted at Dankook University Hospital Pediatric Department in Jan. 1995~May. 1998. We analyzed quantatively the results of acute reactive marker(CRP, ESR, WBC), pyuria, fever and compared to those of sonographically find ing and $^{99m}TC$-DMSA renal scan. Comparison between groups were performed by the chi-square (x2) test and a p value of less than 0.05 was considered statistically significant. Results : 1) The number of boys less than 1 year of age was larger than that of girls. But the number of boys more than 1 year of age was reversed. 2) The higher me level of reactive marker (CRP, WBC), the more the probability of upper UTI. 3) The higher fever, the more the probability of upper UTI. 4) The more pyuria, the more probability of upper UTI. 5) The more higher the grade of vesicoureteral reflux, the more probability of upper UTI. 6) $^{99m}TC$-DMSA renal scan is more sensitive and more specific diagnostic tool than renal sonogram. Conclusion : The appearance of an abnormal $^{99m}TC$-DMSA renal scan is correlated with acute reactive marker (CRP, ESR, WBC), fever, pyuria. $^{99m}TC$-DMSA renal scan can be a good valuable predictor tool in upper UTI. So we can start early treatment and decrease the incidence of complication of upper urinary tract by above indicators before knowing the result of urine culture. And we can follow up the patients in more good relationships with their parents by telling them the duration of treatment and follow-up plan.

• Pediatric Infection and Vaccine
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• v.17 no.1
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• pp.30-35
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• 2010

Purpose : We investigated the causative organism and its antibiotic susceptibility of community acquired urinary tract infection (UTI) in children at a secondary hospital to test the adequacy of the current guidelines. Methods : Children diagnosed with UTI at the Department of Pediatrics, Kwandong University MyMyongji Hospital by pyuria and bacterial growth of greater than $1.0{\times}10^5CFU/mL$ on clean catch midstream urine from January 2005 to December 2008 were studied retrospectively. The epidemiologic data, causative organism, and the antibiotic susceptibility were analyzed. Results : Sixty two children were diagnosed with sixty four cases of UTI's. Two bacteria were isolated in one case and thus data on 65 urine cultures were analyzed. The male:female ratio was 1.6:1 and 78.1% were less than 12 months of age. Escherichia coli was the predominant cause consisting of 53 cases (82.8%) of the cases. K. pneumoniae (5), Enterobacter (4), Enterococcus (1), $\beta$-streptococcus (1), Diphtheroides (1) were isolated. The antibiotic resistance of E. coli were as follows; ampicillin 69.8%, cefotaxime 1.9%, gentamicin 15.1%, amikacin 0.0%, levofloxacin 1.9%, and trimethoprim/sulfamethoxazole 26.4 %. Only one case of the E. coli was extended spectrum $\beta$-lactamase (ESBL) positive. Conclusion : Compared to prior reports from other tertiary hospitals in Korea, E. coli was the predominant cause in childhood UTI and the rate of ESBL positivity was low. The antibiotic resistance was also different compared to prior reports. We conclude that a difference in the cause and antibiotic resistance of childhood UTI exists between centers and this should be taken into consideration when prescribing antibiotics for childhood UTIs.

• Pediatric Infection and Vaccine
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• v.15 no.1
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• pp.36-44
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• 2008

Purpose : Orbital cellulitis is rare, but it could be from the serious complication of sinusitis in children. It is often difficult to distinguish periorbital cellulitis from orbital cellulitis. The purpose of this study is to describe the clinical features of orbital and periorbital cellulitis in a pediatric population and to assess the predisposing factors and their complications. Methods : Forty-one patients aged 18 years and younger who were admitted between January 2000 and December 2006 to Hanil General Hospital and Kyunghee University Hospital with orbital or periorbital cellulitis. The retrospective analyses included clinical characteristics of orbital and periorbital cellulitis, dermographics, past history, predisposing factors, clinical presentations, treatments, and complications. Results : Among 41 patients, 34 patients had periorbital cellulitis, 7 patients had orbital cellulitis. While paranasal sinus disease was the most common predisposing cause in orbital cases, skin lesion, insect bite, dacrocystitis and conjunctivitis were the common causes in periorbital cases. In comparison with periorbital cases, orbital cases had higher level of white blood cell count, erythrocyte sedimentation rate, and C-reactive protein. Blood cultures were taken in 23 patients, but only one had Staphylococcus aureus from blood. Only one case had surgical incision and drainage and recovered without complications. Conclusion : From the results of our data, when patient shows erythematous swelling of periorbital area with opthalmoplegia, chemosis and proptosis, orbital CT scan is required to make diagnosis of orbital cellulitis. Most cases of orbital cellulitis can be treated successfully without surgical intervention. If there is no clinical improvement, repeated CT scan and/or surgical intervention should be considered.

• Pediatric Infection and Vaccine
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• v.15 no.1
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• pp.52-58
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• 2008

Purpose : Whole blood interferon-$\gamma$ assay was developed and many studies showed its usefulness in diagnosing tuberculosis (TB) including latent tuberculosis infection (LTBI). However, assessment in children has been limited. This study was undertaken to evaluate the usefulness of QuantiFERON-TB Gold for the diagnosis of LTBI in children exposed to pulmonary TB. Methods : Children who visited Seoul National University Bundang Hospital with a history of TB exposure were enrolled from January 2006 to December 2007. They were evaluated with chest x-rays, tuberculin skin test (TST) and QuantiFERON-TB Gold test. TST was retested 3 months later for those with initial negative reactivity. Definition of LTBI was made on the basis of the TST reactivity. Results : Among the 103 children with a history of TB exposure, 49 children were tested with chest x-ray, TST, and QuantiFERON-TB Gold. Twenty-two were males. Median age was 7.5 years (range; 3 months to 14.7 years). According to TST reactivity, LTBI was in 8 (19%), no infection was in 21 (50%), possible LTBI was in 13 (31%). QuantiFERON-TB Gold test was positive in 5 of the 49 subjects (10%); 3 of the 13 subjects (23.1%) in unknown status, 1 of the 8 subjects (13%) in LTBI, and 1 of the 21 subjects (5%) without infection. The agreement between the QuantiFERON-TB Gold and the TST was poor (${\kappa}=0.101$). Conclusion : QuantiFERON-TB Gold showed poor sensitivity for the diagnosis of LTBI in children with exposure to TB. QuantiFERON-TB Gold alone does not seem to be useful in the diagnosis of LTBI in children.

• Pediatric Infection and Vaccine
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• v.15 no.1
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• pp.59-67
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• 2008

Purpose : According to the 2008 WHO report, incidence, prevalence, and mortality of tuberculosis are decreasing globally. The 7th National Tuberculosis Survey of 1995 in Korea showed that the prevalence of tuberculosis was also decreasing. This study was performed to review the hospitalized childhood tuberculosis in a children's hospital over a 20 year period. Methods : Medical records of children <16 years of age hospitalized with the diagnosis of tuberculosis at the Seoul National University Children's Hospital between 1988 and 2007 were reviewed retrospectively. Changes in number of patients and involved sites were also analyzed by four 5-year periods. Results : Out of the 186 hospitalized patients, 59.1% were male. Median age at diagnosis was 5.5 years old (range, 10 days-15 years). The main involved sites included the lung (n=54, 29%) or pleura (n=12, 6.5%), central nervous system (n=49, 26.3%), lymph node (n=15, 8.1 %), bone and joint (n=9, 4.8%), gastrointestinal tract (n=5, 2.7%) or peritoneum (n=5, 2.7%), pericardium (n=2, 1.1%) and others (n=3, 1.6%). Total 32 patients (17.2%) showed miliary pattern. The proportion of hospitalization with newly diagnosed tuberculosis among all cause hospitalization decreased from 0.61% to 0.09%, comparing the period of 1988-1992 and 2003-2007 (P<0.001) and the incidence of hospitalized tuberculosis of any involved organs also decreased with a statistical significance. Conclusion : The data from a single children's hospital suggest that the number of hospitalized childhood patients with tuberculosis has decreased over a 20 year period in Korea.