• Title/Summary/Keyword: reliable

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Tokamak plasma disruption precursor onset time study based on semi-supervised anomaly detection

  • X.K. Ai;W. Zheng;M. Zhang;D.L. Chen;C.S. Shen;B.H. Guo;B.J. Xiao;Y. Zhong;N.C. Wang;Z.J. Yang;Z.P. Chen;Z.Y. Chen;Y.H. Ding;Y. Pan
    • Nuclear Engineering and Technology
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    • v.56 no.4
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    • pp.1501-1512
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    • 2024
  • Plasma disruption in tokamak experiments is a challenging issue that causes damage to the device. Reliable prediction methods are needed, but the lack of full understanding of plasma disruption limits the effectiveness of physics-driven methods. Data-driven methods based on supervised learning are commonly used, and they rely on labelled training data. However, manual labelling of disruption precursors is a time-consuming and challenging task, as some precursors are difficult to accurately identify. The mainstream labelling methods assume that the precursor onset occurs at a fixed time before disruption, which leads to mislabeled samples and suboptimal prediction performance. In this paper, we present disruption prediction methods based on anomaly detection to address these issues, demonstrating good prediction performance on J-TEXT and EAST. By evaluating precursor onset times using different anomaly detection algorithms, it is found that labelling methods can be improved since the onset times of different shots are not necessarily the same. The study optimizes precursor labelling using the onset times inferred by the anomaly detection predictor and test the optimized labels on supervised learning disruption predictors. The results on J-TEXT and EAST show that the models trained on the optimized labels outperform those trained on fixed onset time labels.

High-resolution medium-range streamflow prediction using distributed hydrological model WRF-Hydro and numerical weather forecast GDAPS (분포형 수문모형 WRF-Hydro와 기상수치예보모형 GDAPS를 활용한 고해상도 중기 유량 예측)

  • Kim, Sohyun;Kim, Bomi;Lee, Garim;Lee, Yaewon;Noh, Seong Jin
    • Journal of Korea Water Resources Association
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    • v.57 no.5
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    • pp.333-346
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    • 2024
  • High-resolution medium-range streamflow prediction is crucial for sustainable water quality and aquatic ecosystem management. For reliable medium-range streamflow predictions, it is necessary to understand the characteristics of forcings and to effectively utilize weather forecast data with low spatio-temporal resolutions. In this study, we presented a comparative analysis of medium-range streamflow predictions using the distributed hydrological model, WRF-Hydro, and the numerical weather forecast Global Data Assimilation and Prediction System (GDAPS) in the Geumho River basin, Korea. Multiple forcings, ground observations (AWS&ASOS), numerical weather forecast (GDAPS), and Global Land Data Assimilation System (GLDAS), were ingested to investigate the performance of streamflow predictions with highresolution WRF-Hydro configuration. In terms of the mean areal accumulated rainfall, GDAPS was overestimated by 36% to 234%, and GLDAS reanalysis data were overestimated by 80% to 153% compared to AWS&ASOS. The performance of streamflow predictions using AWS&ASOS resulted in KGE and NSE values of 0.6 or higher at the Kangchang station. Meanwhile, GDAPS-based streamflow predictions showed high variability, with KGE values ranging from 0.871 to -0.131 depending on the rainfall events. Although the peak flow error of GDAPS was larger or similar to that of GLDAS, the peak flow timing error of GDAPS was smaller than that of GLDAS. The average timing errors of AWS&ASOS, GDAPS, and GLDAS were 3.7 hours, 8.4 hours, and 70.1 hours, respectively. Medium-range streamflow predictions using GDAPS and high-resolution WRF-Hydro may provide useful information for water resources management especially in terms of occurrence and timing of peak flow albeit high uncertainty in flood magnitude.

Lived experience of mothers who have child with cerebral palsy (뇌성마비아 어머니의 경험)

  • Lee Hwa Za;Kim Yee Soon;Lee Gee Won;Gwan Soo Za;Kang In Soon;An Hea Gyung
    • Child Health Nursing Research
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    • v.2 no.1
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    • pp.93-111
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    • 1996
  • The purpose of the study is to identify the lived experience of mothers who have children with cerebral palsy in order to understand their agony. Moreover, the result of study was to find some nursing intervention for disabled children and their mothers. For this purpose, ten mothers who are willing to cooperate with this research were selected at random from those who have children with the cerebral palsy, currently using the municipal facilities for the handicapped with cerebral malfunction. Data collection was done from October 4, 1994 th December 31, 1994. The data were collected by asking the mothers mentioned above with some unstructured open-ended questions, recorded on the tapes with permission by the interviewee in order to prevent missing of the interviewed contents. These collected data have been substantiated and properly analyzed on the basis of phenomenological approach initiated by Colaizzi's method. The results and validity are proved to be credible by means of the individual checking of the interviewed mothers. The results of this study are as follows : 1. When the mother is first informed of the diagnosis of cerebral palsy on her child, she usually misses the crucial timing needed for proper treatment of the child's disorder because she is notified through the doctor's indifference and his apparently inactive, matter-of-fact attitude. At first she suspects the doctor's diagnosis and tries to attribute it to the unknown cause from a certain genetic problem and then she quickly wants to deny the whole situation that her child is really suffering from the cerebral palsy. The reality is too much for her to accept as it is and she would not believe her child is abnormal. Therefore, she even attempts depend on the power of God for its solution. 2. The mother, who goes thorough this kind of uncommon experiences, is totally devoted to the treatment and care of the child and completely ignores her own life and happiness. At the same time, she feels sorry for her other normal children she believes having not enough care and concern. Also, she feels sorry for the sick child when the child's brothers or sisters show special concern for the patient out of sympathy. It is sorry and not satisfied for her that the child is growing with abnormality and neighbor other around have inappropriate attitudes. Likewise, she is discontent with her husband's lack of concern about the child's treatment. She believes that the health care system in this society isn't fulfilling its due purpose. In the state of her utmost distress and anxiety, she always feels the need of competent consultants, and is angry about that her child is treated as an abnormal being, she is trying to hide the child from other people and to make him or her disappear, if possible. Although she doesn't have harmonious relation with her husband, she id happy when he shows his affection for the child and she feels relieved and thankful when the relatives don't mention about the child's condition Since the child's overall status of health is continuously in unstable conditions, requiring her all-time readiness for an emergency, she feels guilty of her child's illness toward the fEmily members as if it was her own fault to have borne such an abnormal child and she feels responsible for the child morally and financially if necessary Because her life is centered on taking care of the child, she cannot afford to enjoy her own life and happiness. She is a lonely mother, fatigued, with no proper relationship with other people around her. With this sense of guilt and responsibility as a mother of an unusual disease, she has no choice but to grieve her destiny from which she is not allowed to escape. 3. Nevertheless, the mother with the child suffering from the cerebral palsy does not easily give up the hope of getting her child cured and she believes that in the long run, though slower than hoped, her abnormal son or daughter will be eventually cured to become a normal sibling someday. This kind of hope is sustained by the mother's strong faith coming from observing the progress of other similar children getting better. Sometimes she is encouraged to have this faith by other mothers who share the same painful experiences, believing that her child will improve even more rapidly than others with the same palsy. Full of hope, she painstakingly waits for the child's healing. Moreover, she plans to have another child. she thinks that the patient child's brothers and sisters only can truly understand and look after the patients. However, when she notices that the progress of other children under the treatment does not look so hopeful, she is distressed by the thoughts that her child may never get well. Too, she is worried that the patient's brother or sister will be born as the same invalid with the cerebral disease. She is discouraged to have another baby as much as she is encouraged to. She is also troubled by the thought that in case she has another baby, she will have to be forced. to neglect the patient child, especially when she does have an extra hand or some reliable person to help her with taking care of the patient.

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Ultrasonographic study on the masseter muscle thickness of adult Korean (한국인 성인의 교근 두께에 관한 초음파검사적 연구)

  • Cha, Bong-Kuen;Park, In-Woo;Lee, Yeun-Hee
    • The korean journal of orthodontics
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    • v.31 no.2 s.85
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    • pp.225-236
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    • 2001
  • It is widely accepted that the shape and structure of bone are closely related to the activity of attached muscle. Numerous clinical and animal experimental studies indicated the significant effects of masticatory muscle function on maxillofacial morphology. Recently, the development of ultrasonography has spread throughout different fields of medicine. In the clinical examinations, ultrasonography is a convenient, inexpensive technique to apply with accurate and reliable results. The aim of this study is to assess the thickness of the masseter muscle and its correlation to maxillofacial skeleton by examining 35 male and 15 female dental students at Kangnung National University. The masseter muscle thickness of the subjects were measured by ultrasonographic scanning with a 7.5MHz linear probe, and their maxillofacial morphology were investigated by lateral cephalometric radiographs. The relationship between the masseter muscle thickness and maxillofacial morphology of normal adult was statistically analyzed, and the following results were obtained. 1. The average thickness of male masseter muscle was 13.8${\pm}$1.71mm in the relaxed state and 14.8${\pm}$1.77mm at maximal clenching state, while that of female was 11.6${\pm}$1.58mm and 12.4${\pm}$1.47mm, respectively. Ethnic difference in thickness of the masseter muscle and maxillofacial skeleton was found when the results of many researchers were compared with those of this study. 2. The thickness of the masseter muscle in both sexes increased significantly at maximal clenching state than in relaxed state(P<0.05). 3. The masseter muscle thickness of male was greater than that of female both in the relaxed state and maximal clenching states(P<0.05). 4. In males, the thickness of the masseter muscle was negatively correlated with the mandibular plane angle and positively correlated with the mandibular ramus height and anterior cranial base length(P<0.05). It may suggest that the male with thicker masseter muscle has smaller facial divergence. 5. No significant correlation was found between the masseter muscle thickness and maxillofacial morphology in females(P<0.05). Therefore, these data suggest that ultrasonography can add valuable information to the conventional examinations of masseter muscle function.

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The Pattern Analysis of Financial Distress for Non-audited Firms using Data Mining (데이터마이닝 기법을 활용한 비외감기업의 부실화 유형 분석)

  • Lee, Su Hyun;Park, Jung Min;Lee, Hyoung Yong
    • Journal of Intelligence and Information Systems
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    • v.21 no.4
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    • pp.111-131
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    • 2015
  • There are only a handful number of research conducted on pattern analysis of corporate distress as compared with research for bankruptcy prediction. The few that exists mainly focus on audited firms because financial data collection is easier for these firms. But in reality, corporate financial distress is a far more common and critical phenomenon for non-audited firms which are mainly comprised of small and medium sized firms. The purpose of this paper is to classify non-audited firms under distress according to their financial ratio using data mining; Self-Organizing Map (SOM). SOM is a type of artificial neural network that is trained using unsupervised learning to produce a lower dimensional discretized representation of the input space of the training samples, called a map. SOM is different from other artificial neural networks as it applies competitive learning as opposed to error-correction learning such as backpropagation with gradient descent, and in the sense that it uses a neighborhood function to preserve the topological properties of the input space. It is one of the popular and successful clustering algorithm. In this study, we classify types of financial distress firms, specially, non-audited firms. In the empirical test, we collect 10 financial ratios of 100 non-audited firms under distress in 2004 for the previous two years (2002 and 2003). Using these financial ratios and the SOM algorithm, five distinct patterns were distinguished. In pattern 1, financial distress was very serious in almost all financial ratios. 12% of the firms are included in these patterns. In pattern 2, financial distress was weak in almost financial ratios. 14% of the firms are included in pattern 2. In pattern 3, growth ratio was the worst among all patterns. It is speculated that the firms of this pattern may be under distress due to severe competition in their industries. Approximately 30% of the firms fell into this group. In pattern 4, the growth ratio was higher than any other pattern but the cash ratio and profitability ratio were not at the level of the growth ratio. It is concluded that the firms of this pattern were under distress in pursuit of expanding their business. About 25% of the firms were in this pattern. Last, pattern 5 encompassed very solvent firms. Perhaps firms of this pattern were distressed due to a bad short-term strategic decision or due to problems with the enterpriser of the firms. Approximately 18% of the firms were under this pattern. This study has the academic and empirical contribution. In the perspectives of the academic contribution, non-audited companies that tend to be easily bankrupt and have the unstructured or easily manipulated financial data are classified by the data mining technology (Self-Organizing Map) rather than big sized audited firms that have the well prepared and reliable financial data. In the perspectives of the empirical one, even though the financial data of the non-audited firms are conducted to analyze, it is useful for find out the first order symptom of financial distress, which makes us to forecast the prediction of bankruptcy of the firms and to manage the early warning and alert signal. These are the academic and empirical contribution of this study. The limitation of this research is to analyze only 100 corporates due to the difficulty of collecting the financial data of the non-audited firms, which make us to be hard to proceed to the analysis by the category or size difference. Also, non-financial qualitative data is crucial for the analysis of bankruptcy. Thus, the non-financial qualitative factor is taken into account for the next study. This study sheds some light on the non-audited small and medium sized firms' distress prediction in the future.

Element Dispersion and Wall-rock Alteration from Daebong Gold-silver Deposit, Republic of Korea (대봉 금-은광상의 모암변질과 원소분산 특성 연구)

  • Yoo, Bong-Chul;Chi, Se-Jung;Lee, Gil-Jae;Lee, Jong-Kil;Lee, Hyun-Koo
    • Economic and Environmental Geology
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    • v.40 no.6
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    • pp.713-726
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    • 2007
  • The Daebong deposit consists of gold-silver-bearing mesothermal massive quartz veins which fill fractures along fault zones($N10{\sim}20^{\circ}W,\;40{\sim}60^{\circ}SW$) within banded gneiss or granitic gneiss of Precambrian Gyeonggi massif. Ore mineralization of the deposit is composed of massive white quartz vein(stage I) which was formed in the same stage by multiple episodes of fracturing and healing and transparent quartz vein(stage II) which is separated by a major faulting event. The hydrothermal alteration of stage I is sericitization, chloritization, carbonitization, pyritization, silicification and argillization. Sericitic zone occurs near and at quartz vein and includes mainly sericite, quartz, and minor illite, carbonates and epidote. Chloritic zone occurs far from quartz vein and is composed of mainly chlorite, quartz and minor sericite, carbonates and epidote. Fe/(Fe+Mg) ratios of sericite and chlorite range 0.36 to 0.59($0.51{\pm}0.10$) and 0.66 to 0.73($0.70{\pm}0.02$), and belong to muscovite-petzite series and brunsvigite, respectively. Calculated $Al_{IV}-Fe/(Fe+Mg)$ diagrams of sericite and chlorite suggest that this can be a reliable indicator of alteration temperature in Au-Ag deposits. Calculated activities of chlorite end member are $a3(Fe_5Al_2Si_3O_{10}(OH){_6}=0.00964{\sim}0.0291,\;a2(Mg_5Al_2Si_3O_{10}(OH){_6}= 9.99E-07{\sim}1.87E-05,\;a1(Mg_6Si_4O_{10}(OH){_6}=5.61E-07{\sim}1.79E-05$. It suggest that chlorite from the Daebong deposit is iron-rich chlorite formed due to decreasing temperature from $T>450^{\circ}C$. Calculated $log\;{\alpha}K^+/{\alpha}H^+,\;log\;{\alpha}Na^+/{\alpha}H^+,\;log\;{\alpha}Ca^{2+}/{\alpha}^2H^+$ and pH values during wall-rock alteration are $4.6(400^{\circ}C),\;4.1(350^{\circ}C),\;4.0(400^{\circ}C),\;4.2(350^{\circ}C),\;1.8(400^{\circ}C),\;4.5(350^{\circ}C),\;5.4{\sim}6.5(400^{\circ}C)\;and\;5.1{\sim}5.5(350^{\circ}C)$, respectively. Gain elements (enrichment elements) during wallrock alteration are $K_2O,\;P_2O_5,\;Na2O$, Ba, Sr, Cr, Sc, V, Pb, Zn, Be, Ag, As, Ta and Sb. Elements(Sr, V, Pb, Zn, As, Sb) represent a potentially tools for exploration in mesothermal and epithermal gold-silver deposits.

A Study on the Critical Success Factors of Social Commerce through the Analysis of the Perception Gap between the Service Providers and the Users: Focused on Ticket Monster in Korea (서비스제공자와 사용자의 인식차이 분석을 통한 소셜커머스 핵심성공요인에 대한 연구: 한국의 티켓몬스터 중심으로)

  • Kim, Il Jung;Lee, Dae Chul;Lim, Gyoo Gun
    • Asia pacific journal of information systems
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    • v.24 no.2
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    • pp.211-232
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    • 2014
  • Recently, there is a growing interest toward social commerce using SNS(Social Networking Service), and the size of its market is also expanding due to popularization of smart phones, tablet PCs and other smart devices. Accordingly, various studies have been attempted but it is shown that most of the previous studies have been conducted from perspectives of the users. The purpose of this study is to derive user-centered CSF(Critical Success Factor) of social commerce from the previous studies and analyze the CSF perception gap between social commerce service providers and users. The CSF perception gap between two groups shows that there is a difference between ideal images the service providers hope for and the actual image the service users have on social commerce companies. This study provides effective improvement directions for social commerce companies by presenting current business problems and its solution plans. For this, This study selected Korea's representative social commerce business Ticket Monster, which is dominant in sales and staff size together with its excellent funding power through M&A by stock exchange with the US social commerce business Living Social with Amazon.com as a shareholder in August, 2011, as a target group of social commerce service provider. we have gathered questionnaires from both service providers and the users from October 22, 2012 until October 31, 2012 to conduct an empirical analysis. We surveyed 160 service providers of Ticket Monster We also surveyed 160 social commerce users who have experienced in using Ticket Monster service. Out of 320 surveys, 20 questionaries which were unfit or undependable were discarded. Consequently the remaining 300(service provider 150, user 150)were used for this empirical study. The statistics were analyzed using SPSS 12.0. Implications of the empirical analysis result of this study are as follows: First of all, There are order differences in the importance of social commerce CSF between two groups. While service providers regard Price Economic as the most important CSF influencing purchasing intention, the users regard 'Trust' as the most important CSF influencing purchasing intention. This means that the service providers have to utilize the unique strong point of social commerce which make the customers be trusted rathe than just focusing on selling product at a discounted price. It means that service Providers need to enhance effective communication skills by using SNS and play a vital role as a trusted adviser who provides curation services and explains the value of products through information filtering. Also, they need to pay attention to preventing consumer damages from deceptive and false advertising. service providers have to create the detailed reward system in case of a consumer damages caused by above problems. It can make strong ties with customers. Second, both service providers and users tend to consider that social commerce CSF influencing purchasing intention are Price Economic, Utility, Trust, and Word of Mouth Effect. Accordingly, it can be learned that users are expecting the benefit from the aspect of prices and economy when using social commerce, and service providers should be able to suggest the individualized discount benefit through diverse methods using social network service. Looking into it from the aspect of usefulness, service providers are required to get users to be cognizant of time-saving, efficiency, and convenience when they are using social commerce. Therefore, it is necessary to increase the usefulness of social commerce through the introduction of a new management strategy, such as intensification of search engine of the Website, facilitation in payment through shopping basket, and package distribution. Trust, as mentioned before, is the most important variable in consumers' mind, so it should definitely be managed for sustainable management. If the trust in social commerce should fall due to consumers' damage case due to false and puffery advertising forgeries, it could have a negative influence on the image of the social commerce industry in general. Instead of advertising with famous celebrities and using a bombastic amount of money on marketing expenses, the social commerce industry should be able to use the word of mouth effect between users by making use of the social network service, the major marketing method of initial social commerce. The word of mouth effect occurring from consumers' spontaneous self-marketer's duty performance can bring not only reduction effect in advertising cost to a service provider but it can also prepare the basis of discounted price suggestion to consumers; in this context, the word of mouth effect should be managed as the CSF of social commerce. Third, Trade safety was not derived as one of the CSF. Recently, with e-commerce like social commerce and Internet shopping increasing in a variety of methods, the importance of trade safety on the Internet also increases, but in this study result, trade safety wasn't evaluated as CSF of social commerce by both groups. This study judges that it's because both service provider groups and user group are perceiving that there is a reliable PG(Payment Gateway) which acts for e-payment of Internet transaction. Accordingly, it is understood that both two groups feel that social commerce can have a corporate identity by website and differentiation in products and services in sales, but don't feel a big difference by business in case of e-payment system. In other words, trade safety should be perceived as natural, basic universal service. Fourth, it's necessary that service providers should intensify the communication with users by making use of social network service which is the major marketing method of social commerce and should be able to use the word of mouth effect between users. The word of mouth effect occurring from consumers' spontaneous self- marketer's duty performance can bring not only reduction effect in advertising cost to a service provider but it can also prepare the basis of discounted price suggestion to consumers. in this context, it is judged that the word of mouth effect should be managed as CSF of social commerce. In this paper, the characteristics of social commerce are limited as five independent variables, however, if an additional study is proceeded with more various independent variables, more in-depth study results will be derived. In addition, this research targets social commerce service providers and the users, however, in the consideration of the fact that social commerce is a two-sided market, drawing CSF through an analysis of perception gap between social commerce service providers and its advertisement clients would be worth to be dealt with in a follow-up study.

The Quantitative Assessment of Renal Function and Size by Differences of Acquisition Counts in $^{99m}Tc$-DMSA Renal Scan ($^{99m}Tc$-DMSA 신장검사에서 획득 계수의 차이에 따른 기능 및 형태 평가)

  • Shim, Dong-Oh;Kim, Ho-Sung;Chung, Eun-Mi
    • The Korean Journal of Nuclear Medicine Technology
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    • v.14 no.2
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    • pp.117-121
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    • 2010
  • Purpose: In nuclear medicine study, there are two methods, preset count method and preset time method, to acquire static images. We usually use preset count method for static image in $^{99m}Tc$-DMSA renal scan, but occasionally use preset time method. In case of using preset count method, we always acquire same counts but it causes a difference of scan time. In case of using preset time method, it takes same scan time to acquire images but it causes different counts. Therefore, the purpose of this study is to investigate any differences of function and formal information in both kidney by acquisition counts Materials and Methods: From January 11, 2010 to March 31, 2010, we analyzed the 30 patients (M: 11, W: 19). who were examined by $^{99m}Tc$-DMSA scan and have one side of functioning kidney relatively between 40~60%. And the patients who have cold and hot region in image were analyzed but we did not accept images of patients when it was hard to divide kidney into cortex. There was no division between subjects and age of subjects is $14.83{\pm}22.07$ old. We used the BrightView gamma camera from PHILIPS. To analyze function and formal of kidney, we used JET stream release 3.0 version from PHILIPS. Using SPSS 12.0 program, we compared descriptive statistics and paired T-test. Images were acquired sequentially in the same parameters, but there are three methods which different from acquisition time and scan time, 100 kcounts, 300 kcounts and 7 minutes method (exceed 300 kcounts). To assess function and formal information of kidney, we measured renal relative function, geometric mean and size of kidney and analyzed each difference. Results: In case of renal relative function in both kidney, 100 kcounts method was $50.52{\pm}3.64%$. 300 kcounts method was $50.38{\pm}3.66%$ and 7 minutes method was $49.91{\pm}3.40%$ and there were no statistical significant differences between each method. In case of geometric mean, 100 kcounts method was $50.08{\pm}3.25%$. 300 kcounts method was $49.89{\pm}3.40%$ and 7 minutes method was $49.91{\pm}3.24%$. And also, there were no statistical significant differences. When comparing size of kidney, 100 kcounts method was $8.23{\pm}1.96$ cm. 300 kcounts method was $8.12{\pm}1.90$ cm and 7 minutes method was $8.35{\pm}1.97$ cm. In case of right kidney, 100 kcounts method was $7.91{\pm}1.88$ cm. 300 kcounts method was $8.12{\pm}1.90$ cm and 7 minutes method was $8.25{\pm}1.96$ cm. From those values, we recognized that there were significant differences each method (p<0.05). Conclusion: From results of this study, there were no statistical differences in renal relative function and geometric mean by acquisition counts. However, in shape of kidney, the more acquisition counts are increasing, the more size of kidney is getting big. And there were statistical significant differences. Therefore, to perform reliable quantitative result, preset count method is more desirable than preset time method. Especially, in case of a follow-up test, if we use preset time method, it will cause differences of formal results in kidney due to acquisition counts each time we examine patients.

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Evaluation of Standardized Uptake Value and Metabolic Tumor Volume between Reconstructed data and Re-sliced data in PET Study (PET 검사 시 Reconstructed data와 Re-sliced data의 표준섭취계수와 Metabolic Tumor Volume의 비교 평가)

  • Do, Yong Ho;Lee, Hong Jae;Kim, Jin Eui
    • The Korean Journal of Nuclear Medicine Technology
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    • v.20 no.2
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    • pp.3-8
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    • 2016
  • Purpose SUV is one of the parameters that assist diagnosis in origin, metastasis and staging of cancer. Specially, it is important to compare SUV before and after chemo or radiation therapy to find out effectiveness of treatment. Storing PET data which has no quantitative change is needed for SUV comparison. However, there is a possibility to loss the data in external hard drive or MINIpacs that are managed by department of nuclear medicine. The aim of this study is to evaluate SUV and metabolic tumor volume (MTV) among reconstructed data (R-D) in workstation, R-D and re-sliced data (S-D) in PACS. Materials and Methods Data of 20 patients (aged $60.5{\pm}8.3y$) underwent $^{18}F-FDG$ PET (Biograph truepoint 40, mCT 40, mCT 64, mMR, Siemens) study were analysed. $SUV_{max}$, $SUV_{peak}$ and MTV were measured in liver, aorta and tumor after sending R-D in workstation, R-D and S-D in PACS to syngo.via software. Results R-D of workstation and PACS showed the same value as mean $SUV_{max}$ in liver, aorta and tumor were $2.95{\pm}0.59$, $2.35{\pm}0.61$, $10.36{\pm}6.15$ and $SUV_{peak}$ were $2.70{\pm}0.51$, $2.07{\pm}0.43$, $7.67{\pm}3.73$(p>0.05) respectively. Mean $SUV_{max}$ of S-D in PACS were decreased by 5.18%, 7.22%, 12.11% and $SUV_{peak}$ 2.61%, 3.63%, 10.07%(p<0.05). Correlation between R-D and S-D were $SUV_{max}$ 0.99, 0.96, 0.99 and $SUV_{peak}$ 0.99, 0.99, 0.99. And 2SD in balnd-altman analysis were $SUV_{max}$ 0.125, 0.290, 1.864 and $SUV_{peak}$ 0.053, 0.103, 0.826. MTV of R-D in workstation and PACS show the same value as $14.21{\pm}12.72cm^3$(p>0.05). MTV in PACS was decreased by 0.12% compared to R-D(p>0.05). Correlation and 2SD between R-D and S-D were 0.99 and 2.243. Conclusion $SUV_{max}$, $SUV_{peak}$, MTV showed the same value in both of R-D in workstation and PACS. However, there was statistically difference in $SUV_{max}$, $SUV_{peak}$ of S-D compare to R-D despite of high correlation. It is possible to analyse reliable pre and post SUV if storing R-D in main hospital PACS system.

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Dosimetric Characteristics of Detectors in Measurement of Beam Data for Small Fields of Linear Accelerator (선형가속기의 소조사면에 대한 빔 자료 측정에서 검출기의 선량 특성 분석)

  • Koo, Ki-Lae;Yang, Oh-Nam;Lim, Cheong-Hwan;Choi, Won-Sik;Shin, Seong-Soo;Ahn, Woo-Sang
    • Journal of radiological science and technology
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    • v.35 no.3
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    • pp.265-273
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    • 2012
  • Aquisition of accurate beam data is very important to calculate a reliable dose distribution of the treatment planning system for small radiation fields in intensity-modulated radiation therapy(IMRT) and stereotactic radiosurgery(SRS). For the measurement of small fields, the choice of a suitable detector is important due to the shape gradient in profile penumbra, the lack of lateral electronic equilibrium, and the effect of effective detector volume. Therefore, this study was to analyze the dosimetric characteristics of various detectors in measurement of beam data for small fields of linear accelerator. 0.01cc and 0.13cc ion chambers (CC01 and CC13) and a stereotactic diode detector(SFD) were used for measurement of small fields. The beam data, including the percent depth dose, output factor, and beam profile were acquired under 6 MV and 15 MV photon beams. Measurements were performed with the field size ranging from $2{\times}2cm^2$ to $5{\times}5cm^2$. For $2{\times}2cm^2$ field size, the differences of the ratios of $PDD_{20}$ and $PDD_{10}$ measured by CC01 and SFD detectors were 1.02% and 0.12% for 6 MV and 15 MV photon beams, respectively. For field sizes larger than $3{\times}3cm^2$, the differences of values of $PDD_{20}/PDD_{10}$ obtained from each detector were 1.15% and 0.71% for 6 MV and 15 MV photon beams, respectively. The output factors obtained from CC01 and SFD for $2{\times}2cm^2$ field size were within 0.5% and 1.5% for 6 MV and 15 MV, respectively. The differences in output factor of three detectors for $3{\times}3cm^2$ to $5{\times}5cm^2$ field sizes were within 0.5%. Profile penumbras measured by the SFD, CC01, and CC13 detectors at three depths were average 2.7 mm and 3.5 mm, 3.4 mm and 4.3 mm, and 5.2 mm and 6.1 mm for 6 MV and 15 MV photon beams, respectively. In conclusion, it could be possible to use of the CC01 and SFD detectors for the measurement of percent depth dose and output factor for $2{\times}2cm^2$ field size, and to use of three detectors for $3{\times}3cm^2$ to $5{\times}5cm^2$ field sizes. CC01 and SFD detectors, consider ably smaller than the radiation field, should be used in order to accurately measure the profile penumbra for small field sizes.