• 한국방사선학회논문지
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• 제12권5호
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• pp.677-682
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• 2018

본 연구는 유방 전단파 탄성 초음파에서 탄성도 점수와 변형비를 이용한 방법이 양성과 악성병변의 감별진단에 유용한지를 평가하였다. 탄성 초음파를 시행한 224명을 대상으로 하였으며, 유방조직검사 결과를 바탕으로 후향적인 분석을 하였다. 유방 종괴의 양성과 악성에 따른 5단계의 탄성도 점수와의 동질성 비교는 Fisher's Exact test, 변형비와의 차이검증은 Mann-Whitney U test를 실시하였다. ROC 곡선분석을 통해 악성병변의 예측을 위한 탄성도 점수와 변형비의 최적 cut off 값을 결정하였다. 양성과 악성 결절 군의 분류에 따른 탄성도 점수의 동질성 비교와 변형비의 차이검증 결과에서 각각 통계적으로 유의한 차이를 보였으며(p=.000), ROC 곡선분석에서 양성과 악성 결절의 예측을 위한 탄성도 점수와 변형비의 AUC 0.824, 0.806, cut off 값 3, 4.4로 결정되었다(p=.001). 따라서 탄성도 점수와 변형비는 유방 종괴의 감별진단에 도움을 줄 수 있을 것이다.

• 한국방사선학회논문지
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• 제13권4호
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• pp.539-546
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• 2019

간조직 생검은 침습적이며, 합병증의 위험을 동반함에도 불구하고 간섬유화의 정도를 예측하는 표준 진단법으로 적용된다. 이러한 단점을 보완하기 위해 본 연구에서는 만성 C형간염 환자 200명을 대상으로 Fibroscan(R)을 이용하여 간섬유화 등급을 나누고, ROC 곡선을 측정하여 혈청학적검사로 계산되는 FIB-4, APRI, AAR의 유용성과 실질적인 Cut-off value를 알아보고자 하였다. 그 결과 간섬유화 평가를 위해 AAR을 적용하는 것보다는 APRI, FIB-4를 이용하는 것이 적절할 것으로 생각되며, 경한 섬유화 등급을 예측하기 위해서는 APRI, 간경변군인 F4등급에는 FIB-4를 사용하는 것이 유용하다고 판단된다. 혈청학적 간섬유화 표지자의 간편하고 반복 측정이 가능하다는 장점을 이용해 간 섬유화의 경과 관찰 기간을 줄일 수 있으므로 나아가 간경변과 간암의 유병률을 감소시킬 수 있을 것으로 사료된다.

• Asian Pacific Journal of Cancer Prevention
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• 제14권3호
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• pp.1803-1806
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• 2013

Purpose: Carbohydrate antigen (CA) 242 is inversely related to prognosis in many cancers. However, few data regarding CA 242 in esophageal cancer (EC) are available. The aim of this study was to determine the prognostic value of CA 242 and propose an optimum cut-off point in predicting survival difference in patients with esophageal squamous cell carcinoma (ESCC). Methods: A retrospective analysis was conducted of 192 cases. A receiver operating characteristic (ROC) curve for survival prediction was plotted to verify the optimum cuf-off point. Univariate and multivariate analyses were performed to evaluate prognostic parameters for survival. Results: The positive rate for CA 242 was 7.3% (14/192). The ROC curve for survival prediction gave an optimum cut-off of 2.15 (U/ml). Patients with CA 242 ${\leq}$ 2.15 U/ml had significantly better 5-year survival than patients with CA 242 >2.15 U/ml (45.4% versus 22.6%; P=0.003). Multivariate analysis showed that differentiation (P=0.033), CA 242 (P=0.017), T grade (P=0.004) and N staging (P<0.001) were independent prognostic factors. Conclusions: Preoperative CA 242 is a predictive factor for long-term survival in ESCC, especially in nodal-negative patients. We conclude that 2.15 U/ml may be the optimum cuf-off point for CA 242 in predicting survival in ESCC.

• 대한방사선기술학회지:방사선기술과학
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• 제41권4호
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• pp.305-312
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• 2018

The incidence of cardiovascular disease increases rapidly after 40's. The thickness of the epicardial adipose tissue was measured to analyze the risk factors affecting the thickness change. We present the cut off value for the epicardial adipose tissue thickness for high impacted variables. For the study, 547 patients underwent echocardiography, epicardial adipose tissue thickness, body mass index, abdominal subcutaneous fat thickness and diabetes mellitus were used as analytical variables. As a result, multiple regression analysis of age group showed that diabetes mellitus was highly influential in all age group, so we could predict the cut off value for the epicardial adipose tissue thickness for diabetes mellitus. As a result of ROC curve analysis, cut off value of 7.44 mm was obtained with sensitivity of 79.6% and specificity of 60.6% for diab etes variab le. Logistic regression analysis b ased on this value showed that the risk for diab etes increased 6 times with each increase in the thickness of the epicardial adipose tissue. Among the various obesity indexes, epicardial adipose tissue is used as an important index especially to prevent the risk of cardiovascular disease. Therefore, we suggest that the use of echocardiography as a routine screening method for the prevention of cardiovascular disease and metabolic syndrome, which is rapidly increasing in patients over 40's age, will enable more effective monitoring. Radiation is the emission or transmission of energy in the form of waves or particles through space or through a material medium.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2001년도 하계학술대회 논문집
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• pp.809-812
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• 2001

We were fabricated of NiCr thin film resistors on A1$_2$O$_3$and SiO$_2$/Si substrates by dc magnetron sputtering system. The AC characteristics of resistors were studied. The cut-off frequency were found >10 MHz for the resistors with 39 ohm value of Alumina substrates, but the cut-off frequency were found 400 kHz for the resistors with 168 ohm value of SiO$_2$/Si substrates. In high frequency applications, the substrate selection is the most important factor.

• Childhood Kidney Diseases
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• 제25권2호
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• pp.78-83
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• 2021

Background: Uric acid levels in urine are measured using urine specimens 24 hours or by uric acid glomerular filtration rate (UAGFR) with spot urine, which additionally requires a blood sample. This study aimed to investigate whether urinary uric acid creatinine ratio (UUACr) obtained by spot urine alone could be recognized as a substitute for UAGFR value, and hyperuricosuria can be screened by UUACr. UUACr is known to vary with age and regional differences. This study focused on the reference value of each value in Korean young populations. Method: We enrolled Korean subjects 1-20 years with normal kidney function, from a single hospital, classified into 5 age groups, 1-5 years, 6-8 years, 9-12 years, 13-15 years, and 16-20 years. We checked spot urine uric acid, creatinine and serum uric acid, creatinine levels on the same day from February 2014 to December 2018. We measured the average of UAGFR and UUACr in each groups. The UUACr cut-off value of the upper 2 standard deviation (SD) of UAGFR were taken. Results: The upper 2 SD of UUACr (mg/mg) and UAGFR (mg/dL) were determined in all age groups. UUACr decreased with grown up (P=0.000), but UAGFR were not statistically different among the groups. UUACr and UAGFR were not significantly different by gender. UUACr and UAGFR were positively correlated; UUACr cut-off value of upper 2 SD UAGFR (0.54 mg/dL) was 0.65 mg/mg in total age. Conclusions: UUACr could potentially be used to screen for hyperuricosuria.

• Journal of Radiation Protection and Research
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• 제45권4호
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• pp.178-186
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• 2020

Background: Reactor pressure vessel (RV) with internals (RVI) are activated structures by neutron irradiation and volume contaminated wastes. Thus, to develop safe and optimized disposal plan for them at a disposal site, it is important to perform exact activation calculation and evaluate the dose rate on the surface of casks which contain cut-off pieces. Materials and Methods: RV and RVI are subjected to neutron activation calculation via Monte Carlo methodology with MCNP6 and ORIGEN-S program-neutron flux, isotopic specific activity, and gamma spectrum calculation on each component of RV and RVI, and dose rate evaluation with MCNP6. Results and Discussion: Through neutron activation analysis, dose rate is evaluated for the casks containing cut-off pieces produced from decommissioned RV and RVI. For RV cut-off ones, the highest value of dose rate on the surface of cask is 6.97 × 10-1 mSv/hr and 2 m from it is 3.03 × 10-2 mSv/hr. For RVI cut-off ones, on the surface of it is 0.166 × 10-1 mSv/hr and 2 m from it is 1.04 × 10-1 mSv/hr. Dose rates for various RV and RVI cut-off pieces distributed lower than the limit except the one of 2 m from the cask surface of RVI. It needs to adjust contents in cask which carries highly radioactive components in order to decrease thickness of cask. Conclusion: Two types of casks are considered in this paper: box type for very-low-level waste (VLLW) as well as low-level waste (LLW) and cylinder type for intermediate-level waste (ILW). The results will contribute to the development of optimal loading plans for RV and RVI cut-off pieces during the decommissioning of nuclear power plant that can be used to prepare radioactive waste disposal plans for the different types of wastes-ILW, LLW, and VLLW.

• Journal of Preventive Medicine and Public Health
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• 제43권1호
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• pp.9-17
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• 2010

Objectives: Parkinson's disease is one of the most common neurodegenerative diseases in the elderly population. In order to estimate the prevalence of Parkinson's disease in the community, the application of a good screening tool is essential. We evaluated the validity and reliability of a Parkinson's disease screening questionnaire and propose an alternative measure to improve its validity for use in community surveys. Methods: We designed the study in a three-phase approach consisting of a screening questionnaire, neurologic examination, and confirmatory examination. A repeated survey was administered to patients with disease detected in the community and on 150 subjects. We examined internal consistency using Cronbach's alpha test, test-retest reliability using the kappa statistic, and validity using sensitivity, specificity, and ROC curves. Unadjusted odds ratios were utilized for the estimation of weights for each questionnaire item. Results: The Cronbach's alpha of the questionnaire was 0.708. The kappa statistic for test-retest reliability was good to generally fair in most of the items. When newly proposed weighting scores were used, the optimum cut-off value was 7/8. When cut-off value was 5/6 for surveying prevalence in a community, the sensitivity was 0.98, and the specificity was 0.61, with simultaneous improvement in reliability. Conclusions: We recommend 5/6 as the ideal cut-off value for the survey of PD prevalence in community. This questionnaire designed for the Korean community could help future epidemiologic studies of PD.

• 대한물리의학회지
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• 제14권4호
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• pp.29-35
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• 2019

PURPOSE: The aim of this study was to provide the standard value of the Five Times Sit to Stand Test (FTSST) measurement on the daily life independence of the elderly in Korea and examine the effects of this test on their daily lives. METHODS: This study was conducted on elderly people over 65 years of age living in Gyeongsangbuk-do, Korea. FTSST was performed while sitting position on a chair. The subjects were classified into independent and dependent living groups according to their lifestyle, and their influence was then examined through logistic regression analysis. To determine the usefulness and cut-off value of the FTSST, the analysis was performed using the ROC curve. RESULTS: The elderly were more likely to live in a group rather than independently as the FTSST time increased (p<.05) (OR=1.098). The area of the lower part of the ROC curve was .707, and as the FTSST increased, a subject was more likely to live in a group rather than independently (p<.05). The cut-off value was assigned to the point where both the specificity and sensitivity were at the coordinates. The sensitivity and specificity were .626 and .753, respectively at 15.62 seconds. CONCLUSION: The elderly in Korea are more likely to live a group-dependent lifestyle than live independently; the likelihood of this outcome is increased further for every additional second beyond 15.62 seconds. The loss of independence of daily life could be predicted based on the status of a subject's lower leg strength using the FTSST.

• Asian Pacific Journal of Cancer Prevention
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• 제16권9호
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• pp.3875-3879
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• 2015

Background: The neutrophil/lymphocyte ratio (NLR) is a simple index of systemic inflammatory response, and has been shown to be a prognostic indicator in some types of cancer. Inflammation has been implicated in the initiation and progression of thyroid cancer. The aim of this study was to examine the relationship of NLR with papillary thyroid cancer (PTC) and different benign thyroid pathologies like multinodular goiter (MNG) and lymphocytic thyroiditis (LT). Materials and Methods: We retrospectively evaluated the neutrophil, lymphocyte counts and NLR calculated from these parameters of 232 patients with histologically confirmed as multinodular goiter (group MNG) (n=70), lymphocytic thyroiditis (group LT) (n=97), LT with PTC (group LT-PTC) (n=25) and PTC (group PTC) (n=40). The optimal cut-off value for NLR was determined. Results: NLR level was significantly higher in groups LT-PTC and PTC as compared to groups MNG and LT (p<0.05). NLR of LT subgroups according to TSH levels were not different (p>0.05). When we grouped the patients as benign and malignant according to PTC presence, the optimum NLR cut-off point obtained from ROC analysis was 1.91 (sensitivity 89.0% and specificity 54.5%). Conclusions: Since NLR was significantly elevated in group LT-PTC and group PTC, NLR value may give an opinion as a potential marker in differentiation of benign and malign thyroid disorders. For this purpose a cut-off value of 1.91 for NLR may be accepted.