• Journal of radiological science and technology
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• v.36 no.2
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• pp.165-173
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• 2013

This study was the estimation of the dose distribution for proton, prompt gamma rays and proton induced neutron particles, in case of exposing the proton beam to polymer gel dosimeter and water phantom. The polymer gel dosimeter was compositeness material of Gelatin, Methacrylic acid, Hydroquinone, Tetrakis and Distilled water. The density of gel dosimeter was $1.04g/cm^3$ which was similar to water. The 72, 116 and 140 MeV proton beams were used in the simulation. Proton beam interacted with the nuclei of the phantom and the nuclei in excited states emitted prompt gamma rays and proton induced neutron particles during the process of de-excitation. The proton particles, prompt gamma rays, proton induced neutron particles were detected by polymer gel dosimeter and water phantom, respectively. The gap of the axis for gel was 2 mm. The Bragg-peak for proton particles in gel dosimeter was similar to water phantom. The dose distribution for proton and prompt gamma rays in gel dosimeter and water phantom was approximately identical in case of 72, 116 and 140 MeV for proton beam. However, in case of proton induced neutron particles for 72, 116 and 140 MeV proton beam, particles were not detected in gel dosimeter, while the Water phantom absorbed neutron particles. Considering the resulting data, gel dosimeter which was developed in the normoxic state attentively detected the dose distribution for proton beam exposure except proton induced neutron particles.

• Radiation Oncology Journal
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• v.20 no.3
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• pp.283-293
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• 2002

Purpose : A PC based brachytherapy planning system was developed to display dose distributions on simulation images by 2D isodose curve including the dose profiles, dose-volume histogram and 30 dose distributions. Materials and Methods : Brachytherapy dose planning software was developed especially for the Ir-192 source, which had been developed by KAERI as a substitute for the Co-60 source. The dose computation was achieved by searching for a pre-computed dose matrix which was tabulated as a function of radial and axial distance from a source. In the computation process, the effects of the tissue scattering correction factor and anisotropic dose distributions were included. The computed dose distributions were displayed in 2D film image including the profile dose, 3D isodose curves with wire frame forms and dosevolume histogram. Results : The brachytherapy dose plan was initiated by obtaining source positions on the principal plane of the source axis. The dose distributions in tissue were computed on a $200\times200\;(mm^2)$ plane on which the source axis was located at the center of the plane. The point doses along the longitudinal axis of the source were $4.5\~9.0\%$ smaller than those on the radial axis of the plane, due to the anisotropy created by the cylindrical shape of the source. When compared to manual calculation, the point doses showed $1\~5\%$ discrepancies from the benchmarking plan. The 2D dose distributions of different planes were matched to the same administered isodose level in order to analyze the shape of the optimized dose level. The accumulated dose-volume histogram, displayed as a function of the percentage volume of administered minimum dose level, was used to guide the volume analysis. Conclusion : This study evaluated the developed computerized dose planning system of brachytherapy. The dose distribution was displayed on the coronal, sagittal and axial planes with the dose histogram. The accumulated DVH and 3D dose distributions provided by the developed system may be useful tools for dose analysis in comparison with orthogonal dose planning.

• Childhood Kidney Diseases
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• v.7 no.2
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• pp.133-141
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• 2003

Purpose : Idiopathic Membranous Nephropathy(IMN) is a rare renal disease in children. To help better understanding of its clinical course and treatment strategies, we reviewed the clinical manifestations and pathological findings of children with IMN. Methods : Among 58 cases with MN, from 1977 to 2003, 42(72.4%) were hepatitis B virus (HBV) associated and 16(27.6%), 6 males and 10 females, were idiopathic. All cases diagnosed aster 2000 were IMN. Several clinicopathological findings(sex, onset age, proteinuria, serum albumin, cholesterol, creatinine clearance, tubulointerstitial changes, glomerular sclerosis, hypertension, renal vein thrombosis, the use of ACE inhibitor, and immunosuppressive therapy) were compared between the remission and the non-remission group of the patients with IMN. Results : The median onset age was 13.4 years. Clinical manifestations were nephrotic syn-drome(7 cases, 43.8%), gross hematuria(5 cases, 31.3%) and microscopic hematuria with proteinuria(3 cases, 18.8%). Hypertension, hypocalcemic tetany and renal vein thrombosis were accompanied in 2, 1 and 2 cases, respectively. In addition to the typical findings of MN, the kidney biopsies showed segmental sclerosis(5 cases, 31.3%) or global sclerosis(6 cases, 37.5 %), diffuse crescents(1 case), and mild(11 cases, 68.7%) or moderate tubulointerstitial changes(3 cases, 18.8%). Thirteen cases(86.7%) received oral steroid. Among them 2 cases received cyclophophamide and 1 received cyclosporin as well. Ten cases(62.5%) received ACE inhibitors. In the patients followed up, 7 cases(46.7%) became free from proteinuria (remission group) while 8(53.3%) presented continous proteinuria (non-remission group), two (13.3%) of which progressed to renal failure. Clinicopathological findings showed no significant differences between the two groups. Conclusion : With HBV vaccination, HBV associated MN decreased markedly and IMN has taken up most of MN in children. For better understanding of this rare disease, a prospective multicenter study of the clinical course and treatment strategies should be done.

• Childhood Kidney Diseases
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• v.14 no.1
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• pp.42-50
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• 2010

Purpose : The clinical characteristics and associated anomalies in children with solitary kidney (SK) were analyzed retrospectively. Methods : Total 38 children diagnosed to have SK at our hospital between December 1989 and December 2009 were recruited, and the clinical records including imaging studies were retrospectively reviewed. SK was defined as unilateral renal agenesis by imaging studies only, and patients with regression of unilateral dysplastic kidney were excluded. Results : Among total 38 patients, 12 were male. The median age at the diagnosis of SK was 6.5 months (at birth-13 years). SK was detected by prenatal ultrasonography in 14 patients and during work-up for renal or urinary tract diseases in 13 (including urinary tract infection in 7). In 10 patients, SK was detected incidentally. Anomalies in the SK were noted in 17 patients including vesicoureteral reflux in 11. Other anomalies in the genitourinary tract were present in 16 patients, and multi-organ-involving syndromes or chromosomal anomalies were detected in 9. The mean duration of follow-up was 9 years (9 months-20 years). Two patients developed chronic renal failure during follow-up, and the median serum creatinine concentration of the remaining 36 at their last follow-up was 0.6 mg/dL. Conclusion : SK may be isolated and clinically asymptomatic; it is frequently accompanied by other anomalies in genitourinary tract and other organs, some of which can induce progressive renal dysfunction. Early recognition of associated anomalies with SK and regular follow-up is recommended to reduce long-term risk.

• Journal of Marine Bioscience and Biotechnology
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• v.1 no.2
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• pp.91-97
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• 2006

For efficient removal of nitrogenous compounds produced in recirculating aquaculture system, the N removal characteristics of immobilized mixed microorganisms were investigated at various mixing ratios of photosynthetic bacteria (PSB) immobilized in PVA beads or CTA cubes and ammonium utilizing bacteria (AUB) immobilized in PVA beads. On the optimal medium of AUB, the maxium gas production rate was obtained at the mixing ratio of 10:40 (PSB:AUB), and the gas production rate increased as the portion of AUB beads in the mixed beads increased. When the mixing ratios of PSB:AUB beads were 50:0, 40:10, 25:25 and 10:40, the final pHs were measured to be 6.29, 6.01, 5.69 and 5.13, respectively. On the optimal medium of PSB, however, the volume and the rate of gas production decreased remarkably as the portion of AUB beads in the mixed beads increased. The final pH was measured to be approximately 6.5, regardless of the mixing ratio. In the reactions by the mixed culture of PSB cubes and AUB beads, all results showed the same tendency of those by the mixed culture of PSB and AUB beads, but the volume and the rate of gas production decreased remarkably, even with 0.2ml of gas production in control. From all the results, the use of mixed PSB and AUB beads at the ratio of 10:40 seems to be efficient to remove nitrogenous compounds in wastewater from recirculating aquaculture system.

• The Korean Journal of Nuclear Medicine
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• v.39 no.1
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• pp.57-68
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• 2005

Purpose: The objective of this study was to assess attenuation correction algorithms with the $^{137}Cs$ point source for the brain positron omission tomography (PET) imaging process. Materials & Methods: Four different types of phantoms were used in this study for testing various types of the attenuation correction techniques. Transmission data of a $^{137}Cs$ point source were acquired after infusing the emission source into phantoms and then the emission data were subsequently acquired in 3D acquisition mode. Scatter corrections were performed with a background tail-fitting algorithm. Emission data were then reconstructed using iterative reconstruction method with a measured (MAC), elliptical (ELAC), segmented (SAC) and remapping (RAC) attenuation correction, respectively. Reconstructed images were then both qualitatively and quantitatively assessed. In addition, reconstructed images of a normal subject were assessed by nuclear medicine physicians. Subtracted images were also compared. Results: ELEC, SAC, and RAC provided a uniform phantom image with less noise for a cylindrical phantom. In contrast, a decrease in intensity at the central portion of the attenuation map was noticed at the result of the MAC. Reconstructed images of Jaszack and Hoffan phantoms presented better quality with RAC and SAC. The attenuation of a skull on images of the normal subject was clearly noticed and the attenuation correction without considering the attenuation of the skull resulted in artificial defects on images of the brain. Conclusion: the complicated and improved attenuation correction methods were needed to obtain the better accuracy of the quantitative brain PET images.

• Journal of Nutrition and Health
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• v.25 no.2
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• pp.179-186
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• 1992

Dietary intakes of 57 college women were measured by 7-day weight food records(7WR) Nutrient intakes of 7WR were compared with results of using 1-day weighted food records(1WR) and 2-day weighed food records(2WR), 7WR were recorded for 7 consecutive days by subjects and its first two days were chosen to provide 1WR and 2WR Mean nutrient intakes of the group were not significantly different between 1WR or 2WRand 7WR. Within-person variations were found to be greater than between-person variations. The ratio of within- and between-person variability was lowest for the vitamin A and highest for the calcium. Data on 7WR were analyzed to estimate the number of recording days needed to ensure r$\geq$0.9 between observed and turn mean intakes. The 11 to 13 days needed for energy sugar protein and vitamin A and 20 days for calcium The results indicated that the number of days needed varied substantially among individuals for the same nutrient and within individuals for different nutrients.

• Journal of Nutrition and Health
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• v.44 no.1
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• pp.49-60
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• 2011

This study was performed to develop a children's dietary life safety index required by the Special Act on Safety Management of Children's Dietary Life enacted in 2009. An analytical hierarchy process was used to obtain initial weights of dietary life safety evaluation indicators. The Delphi method was applied to develop the weights along with 98 food and nutrition professionals. Three representative policy indicators, nine strategy indicators, 11 main evaluation indicators, and 20 detailed evaluation indicators were selected for the children's dietary life safety assessment. Three policy indicators and nine strategy indicators were the following: children's food safety indicator (support level of children' safety, safety management level of children's favorite foods, and safety management level of institutional food service), children's nutrition safety indicator (management level of missing meals and obesity, nutrition management level of children's favorite foods, and nutrition management level of institutional food service), and children's perception and practice level indicator ("Dietary Life Law" perception level, perception, and practice level for dietary life safety management, perception, and practice level for nutrition management). Weights of 40%, 40%, and 20% were given for the three representative policy indicators. The relative importance of nine strategic indicators, which were determined by the Delphi method is as follows: For children’s food safety, support level of children's safety, safety management level of children's favorite foods, and safety management level of institutional food service were given weights of 12%, 9%, and 19%, respectively. For children's nutrition safety, the missing meals and obesity management level, nutrition management level of children's favorite foods, and the nutrition management level of institutional food service were given weights of 13%, 11%, and 16%, respectively. The "Dietary Life Law" perception level, perception and practice level of dietary life safety management, and perception and practice level of nutrition management were given weights of 4%, 7%, and 9%, respectively.

• Journal of Nutrition and Health
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• v.51 no.1
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• pp.87-102
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• 2018

Purpose: The purpose of this study was to develop a valid instrument for measuring the dietary quality and behaviors of Korean elderly. Methods: The development of the Nutrition Quotient for Elderly (NQ-E) was conducted in three steps: item generation, item reduction, and validation. The 41 items of the NQ-E checklist were derived from a systematic literature review, expert in-depth interviews, statistical analyses of the fifth Korean National Health and Nutrition Examination Survey data, and national nutrition policies and recommendations. Pearson's correlation was used to determine the level of agreement between the questionnaires and nutrient intake level, and 24 items were selected for a nationwide survey. A total of 1,000 nationwide elderly subjects completed the checklist questionnaire. The construct validity of the NQ-E was assessed using confirmatory factor analysis, LISREL. Results: The nineteen checklist items were used as final items for NQ-E. Checklist items were composed of four-factors: food behavior (6 items), balance (4 items), diversity (6 items), and moderation (3 items). The standardized path coefficients were used as the weights of the items. The NQ-E and four-factor scores were calculated according to the obtained weights of the questionnaire items. Conclusion: NQ-E would be a useful tool for assessing the food behavior and dietary quality of the elderly.

• The Journal of Korean Society for Radiation Therapy
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• v.30 no.1_2
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• pp.129-138
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• 2018

Purpose : An aim of this study was to compare the effect of multi leaf collimator(MLC) types for high dimension radiotherapy in treatment sites used clinically. Material and Method : 70 patients with lung cancer, spine cancer, prostate cancer, whole pelvis, head and neck, breast cancer were included in this study. High definition(HD) MLC of TrueBeam STx (Varian Medical system, Palo Alto, CA) and millenium(M) MLC of VitalBeam (Varian Medical system, Palo Alto, CA) were used. Radiotherapy plans were performed for each patient under same treatment goals with Eclipse (Version 13.7, Varian Palo Alto USA, CA). To compare the indicators of the radiotherapy plans, planning target volume(PTV) coverage, conformity index(CI), homogeneity index(HI), and clinical indicators for each treatment sites in normal tissues were evaluated. To evaluate low dose distribution, $V_{30%}$ values were compared according to MLC types. Additionally, length and volume of targets for each treatment sites were investigated. Result : In stereotatictic body radiotherapy(SBRT) plan for lung, the average value of PTV coverage was reduced by 0.52 % with HD MLC. With SBRT plan using HD MLC for spine, the average value of PTV coverage decreased by 0.63 % and maximum dose decreased by 1.13 %. In the test of CI and HI, the values in SBRT plan with HD MLC for spine were 1.144, 1.079 and the values using M MLC were 1.160, 1.092 in SBRT plan for lung, The dose evaluation of critical organ was reduced by 1.48 % in the ipsilateral lung mean dose with HD MLC. In prostate cancer volumetric modulated arc therapy(VMAT) with HD MLC, the mean dose and the $V_{30}$ of bladder and the mean dose and the $V_{25}$ of rectum were reduced by 0.53 %, 1.42 %, 0.97 %, and 0.69 %, respectively (p<0.05). The average value of heart mean dose was reduced by 0.83 % in breast cancer VMAT with M MLC. Other assessment indices for treatment sites showed no significant difference between treatment plans with two types of MLC. Conclusion : Using HD MLC had a positive impact on the PTV coverage and normal tissue sparing in usually short or small targets such as lung and spine SBRT and prostate VMAT. But, there was no significant difference in targets with long and large such as lung, head and neck, and whole pelvis for VMAT.