• The Journal of Advanced Prosthodontics
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• v.8 no.2
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• pp.85-93
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• 2016

PURPOSE. The purpose of this study was to determine the effect of anchorage systems and palatal coverage of denture base on load transfer in maxillary implant-retained overdenture. MATERIALS AND METHODS. Maxillary implant-retained overdentures with 4 implants placed in the anterior region of edentulous maxilla were converted into a 3-D numerical model, and stress distribution patterns in implant supporting bone in the case of unilateral vertical loading on maxillary right first molar were compared with each other depending on various types of anchorage system and palatal coverage extent of denture base using three-dimensional finite element analysis. RESULTS. In all experimental models, the highest stress was concentrated on the most distal implant and implant supporting bone on loaded side. The stress at the most distal implant-supporting bone was concentrated on the cortical bone. In all anchorage system without palatal coverage of denture base, higher stresses were concentrated on the most distal implant and implant supporting bone on loaded side. CONCLUSION. It could be suggested that when making maxillary implant retained overdenture, using Hader bar instead of milled bar and full palatal coverage rather than partial palatal coverage are more beneficial in distributing the stress that is applied on implant supporting bone.

• Progress in Medical Physics
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• v.27 no.4
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• pp.180-188
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• 2016

Acuros XB advanced dose calculation algorithm (AXB, Varian Medical Systems, Palo Alto, CA) has been released recently and provided the advantages of speed and accuracy for dose calculation. For clinical use, it is important to investigate the dosimetric performance of AXB compared to the calculation algorithm of the previous version, Anisotropic Analytical Algorithm (AAA, Varian Medical Systems, Palo Alto, CA). Ten volumetric modulated arc therapy (VMAT) plans for each of the following cases were included: head and neck (H&N), prostate, spine, and lung. The spine and lung cases were treated with stereotactic body radiation therapy (SBRT) technique. For all cases, the dose distributions were calculated using AAA and two dose reporting modes in AXB (dose-to-water, $AXB_w$, and dose-to-medium, $AXB_m$) with same plan parameters. For dosimetric evaluation, the dose-volumetric parameters were calculated for each planning target volume (PTV) and interested normal organs. The differences between AAA and AXB were statistically calculated with paired t-test. As a general trend, $AXB_w$ and $AXB_m$ showed dose underestimation as compared with AAA, which did not exceed within -3.5% and -4.5%, respectively. The maximum dose of PTV calculated by $AXB_w$ and $AXB_m$ was tended to be overestimated with the relative dose difference ranged from 1.6% to 4.6% for all cases. The absolute mean values of the relative dose differences were $1.1{\pm}1.2%$ and $2.0{\pm}1.2%$ when comparing between AAA and $AXB_w$, and AAA and $AXB_m$, respectively. For almost dose-volumetric parameters of PTV, the relative dose differences are statistically significant while there are no statistical significance for normal tissues. Both $AXB_w$ and $AXB_m$ was tended to underestimate dose for PTV and normal tissues compared to AAA. For analyzing two dose reporting modes in AXB, the dose distribution calculated by $AXB_w$ was similar to those of AAA when comparing the dose distributions between AAA and $AXB_m$.

• Journal of the Korean Physical Society
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• v.80
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• pp.516-525
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• 2022

This study is to assess the clinical use of commercial PerFRACTION^TM for patient-specific quality assurance of volumetric-modulated arc therapy. Forty-six pretreatment verification plans for patients treated using a TrueBeam STx linear accelerator for lesions in various treatment sites such as brain, head and neck (H&N), prostate, and lung were included in this study. All pretreatment verification plans were generated using the Eclipse treatment planning system (TPS). Dose distributions obtained from electronic portal imaging device (EPID), ArcCHECK^TM, and two-dimensional (2D)/three-dimensional (3D) PerFRACTION^TM were then compared with the dose distribution calculated from the Eclipse TPS. In addition, the correlation between the plan complexity (the modulation complexity score and the leaf travel modulation complexity score) and the gamma passing rates (GPRs) of each quality assurance (QA) system was evaluated by calculating Spearman's rank correlation coefficient (r_s) with the corresponding p-values. The gamma passing rates of 46 patients analyzed with the 2D/3D PerFRACTION^TM using the 2%/2 mm and 3%/3 mm criteria showed almost similar trends to those analyzed with the Portal dose imaging prediction (PDIP) and ArcCHECK^TM except for those analyzed with ArcCHECK^TM using the 2%/2 mm criterion. Most of weak or moderate correlations between GPRs and plan complexity were observed for all QA systems. The trend of mean rs between GPRs using PDIP and 2D/3D PerFRACTION^TM for both criteria and plan complexity indices as in the GPRs analysis was significantly similar for brain, prostate, and lung cases with lower complexity compared to H&N case. Furthermore, the trend of mean rs for 2D/3D PerFRACTION^TM for H&N case with high complexity was similar to that of ArcCHECK^TM and slightly lower correlation was observed than that of PDIP. This work showed that the performance of 2D/3D PerFRACTION^TM for pretreatment patient-specific QA was almost comparable to that of PDIP, although there was small difference from ArcCHECK^TM for some cases. Thus, we found that the PerFRACTION^TM is a suitable QA system for pretreatment patient-specific QA in a variety of treatment sites.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.15 no.12
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• pp.4400-4419
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• 2021

In the 4th Industrial Revolution, the healthcare industry is undergoing a paradigm shift from post-care and management systems based on diagnosis and treatment to disease prevention and management based on personal precision medicine. To optimize medical services for individual patients, an open ecosystem for the healthcare industry that allows the exchange and utilization of personal health records (PHRs) is required. However, under the current system of hospital-centered data management, it is difficult to implement the linking and sharing of PHRs in practice. To address this problem, in this study, we present the design and implementation of a patient-centered PHR platform using blockchain technology. This platform achieved transparency and reliability in information management by eliminating the risk of leakage and tampering/altering personal information, which could occur when using a PHR. In addition, the patient-consent system was applied to a PHR; thus, the patient acted as the user with ownership. The proposed blockchain-based PHR platform enables the integration of personal medical information with scattered distribution across multiple hospitals, and allows patients to freely use their health records in their daily lives and emergencies. The proposed platform is expected to serve as a stepping stone for patient-centered healthcare data management and utilization.

• The Korean Journal of Cytopathology
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• v.6 no.2
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• pp.85-98
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• 1995

In 1989, the Bethesda System (TBS) was introduced as an attempt to standardize cervical/vaginal reporting systems. TBS nomenclature was created for reporting cytologic diagnoses to replace the currently used Cervical Intraepithelial Neoplasia (CIN) and Papanicolaou Class System, which are deemed less reproducible. The name for preinvasive squamous lesions was changed to squamous intraepithelial lesion(SIL), subdivided into low-grade and high-grade types. TBS recommends a specific format for cytologic report, starling with explicit statement on the adequacy of the specimen, followed by general categorization and descriptive diagnosis. Pathologic and epidemiologic studios performed over last 10 years have provided evidence that human papillomavirus (HPV) plays a significant role in the development of cervical neoplasia, TBS corresponds not only to currently held views of the behavior of preinvasive lesions and their HPV distribution, but also to the current guidelines for clinical management.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.11 no.9
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• pp.4379-4397
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• 2017

Three different improvements of the Velocity-based model were proposed in a minimal velocity-based pedestrian model. The improvements of the models are based on the different agent forms. The different representations of the agent lead to different results, in this paper, we simulated the pedestrian movements in some typical scenes by using different agent forms, and the agent forms included the circles with different radiuses, the ellipse and the multi-circle stand for one pedestrian. We have proposed a novel model of pedestrian dynamics to optimize the simulation. Our model specifies the pedestrian behavior using a dynamic ellipse, which is parameterized by their velocity and can improve the simulaton accuracy. We found a representation of the pedestrian much closer to the reality. The phenomena of the self-organization can be observable in the improved models.

• Korea Journal of Hospital Management
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• v.6 no.1
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• pp.120-146
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• 2001

This study was carried out to provide the essential information in improving the graduate medical education in Korea. For the study, a survey targeting the directors of GME of nationwide teaching hospitals was performed with a questionnaire asking the questions such as the director's perception on the quality of GME, trainees' salary level, trainees' specialty selection tendency, training system and its duration. The collected data were analyzed using t-test, ANOVA, and $x^2$-test. The results were as follows: 1. The survey were executed on 240 teaching hospitals in Korea and the response rate was 66.2% (159 hospitals replied). 2. The bigger a hospitals is the better in Quality of education. Larger hospitals tend to have better status in all items including medical specialists' experience, contents of medical curriculum, general environment for medical education and medical trainees's salary level. The result supported the general perception on the positive relationship between hospital size and Quality of GMA. 3. Providing convenience for medical trainees who prepares for the medical specialist Qualifying examination didn't affect the results of the examination. 4. The directions of GME have a perception that the trainees give positive impact on financial performance of their hospitals. This seems to be one of the reasons that hospitals try to retain as many trainees as possible. 5. The directors of GME considered medical trainees as an educate, and most of them responded positively on the need of governmental supports for the education cost and the trainee's salary. Considering above results, it seems that GME would get more social attention and the trainees' impact on hospitals operation would be increased more than before. In response to these trends, hospitals would find out the ways to lower dependency on trainees, and this change of attitude of hospitals on the GME would cause problems in operation of hospitals and GME itself. In order to prevent these problems the policy on GME should be directed in following ways. 1. The contents of Qualifying examination for specialist should be improved. 2. The curriculum of GME should be strictly followed. 3. The status of trainee in a hospital has to be defined as eductee. 4. Government has to support a half of the education cost and salary of trainee. 5. The distribution of the trainee among the hospital group have to be based on total available. 6. The financial support and welfare of trainee should be improved gradually and systematically.

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.4
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• pp.1621-1626
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• 2014

Background: Breast cancer is the most common malignant tumor in females worldwide. Many differences exist in clinico-pathological characteristics of breast cancer patients between China and Western countries. This study aimed to analyze clinico-pathological characteristics of breast cancer from central China. Methods: Clinico-pathological information on breast cancer from three hospitals in central China was collected and analyzed. Results: From 1994 to 2012, 2,525 patients with a median age 50 years were included in this study. The 45-49-year age group and invasive ductal carcinoma not otherwise specified accounted for the highest proportions (19.1%, 480/2,525 and 81.0%, 1,982/2,446). Stages 0-I, II and III accounted for 28.0% (682/2,441), 48.4% (1,180/2,441), and 23.7% (578/2,441), respectively. Distribution of N stage showed that N0 accounted for 53.2% (1,344/2,525), and proportion of N0 rose from 51.1% (157/307) in 30-39-year age group to 64.3% (110/171) in ${\geq}$ 70-year age group, with an average increase of 2.1% in each age group. Modified radical mastectomy, radical mastectomy, breast-conserving surgery and simple mastectomy were performed for 71.8% (1,812/2,525), 18.0% (454/2,525), 5.2% (131/2,525) and 2.6% (66/2,525), respectively. Proportions of breast-conserving surgery in age ${\leq}$ 44-year group (68/132, 51.5%) and simple mastectomy in age ${\geq}$ 60-year group (57/89, 64.0%) were higher than in the other age groups. Breast cancers positive for estrogen receptor accounted for 53.0% (1,107/ 2,112). The comparisons among this study and other reports showed higher proportion of younger patients, lower proportion of breast-conserving surgery and positive estrogen receptor patients in China than western countries. Conclusions: Clinico-pathological characteristics in this study demonstrated clear differences between the center of China than Western countries. Additional classification systems should be developed to guide grading of early breast cancer more accurately, especially for N0 patients. Invasive ductal carcinoma is a focus for intensive research.

• The Journal of Korean Society for Radiation Therapy
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• v.35
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• pp.7-13
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• 2023

Purpose: In this study, we evaluated the effect of using a customized bolus on dose delivery in the treatment plan when cervical cancer protruded out of the body along with the uterus and evaluated reproducibility in patient set-up. Materials & Methods: The treatment plan used the Eclipse Treatment Planning System (Version 15.5.0, Varian, USA) and the treatment machine was VitalBeam (Varian Medical Systems, USA). The radiotherapy technique used 6 MV energy in the AP/PA direction with 3D-CRT. The prescribed dose is 1.8 Gy/fx and the total dose is 50.4 Gy/28 fx. Semiflex TM31010 (PTW, Germany) was used as the ion chamber, and the dose distribution was analyzed and evaluated by comparing the planned and measured dose according to each position movement and the tumor center dose. The first measurement was performed at the center by applying a customized bolus to the phantom, and the measurement was performed while moving in the range of -2 cm to +2 cm in the X, Y, and Z directions from the center assuming a positional error. It was measured at intervals of 0.5 cm, the Y-axis direction was measured up to ±3 cm, and the situation in which Bolus was set-up incorrectly was also measured. The measured doses were compared based on doses corrected to CT Hounsfield Unit (HU) 240 of silicon instead of the phantom's air cavity. Result: The treatment dose distribution was uniform when the customized bolus was used, and there was no significant difference between the prescribed dose and the actual measured value even when positional errors occurred. It was confirmed that the existing sheet-type bolus is difficult to compensate for irregularly shaped tumors protruding outside the body, but customized Bolus is found to be useful in delivering treatment doses uniformly.

• Journal of the Korean Dietetic Association
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• v.16 no.4
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• pp.378-396
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• 2010

The objectives of this study were to explore hospital foodservice management and to investigate conditions related to health insurance coverage of inpatient meals. A questionnaire was distributed to the nutrition departments of 44 hospitals in Seoul on July 2009. The average kitchen area was 0.5 $m^2$, and centralized distribution systems were in place. Partition walls from contamination zones, separate work tables to prevent cross-contamination, exclusive areas for preparing tube feeding, and split carts with refrigerated and convection heat settings were largely used in tertiary hospitals. Most dietitians did meal rounds (93.2%) and surveyed for patient satisfaction (86.4%). The major theme of QI (Quality Improvement) was menu management (31.8%). The health insurance fees for meals were (won)4,938.9 for a general diet, (won)5,199.8 for a therapeutic diet, (won)4,067.0 for tube feeding, (won)9,950.0 for sterilized diet, and (won)18,383.4 for diets not covered by health insurance. The prices for general and therapeutic diets were significantly lower in hospitals compared to tertiary or general hospitals (P<0.001). The cost composed of 48.3% food, 44.0% labor and 7.7% overhead for general diets and 47.9%, 44.5% and 7.6% for therapeutic diets. In the case of health insurance coverage for patient meals, the number of items applied to general diets averaged 2.8 out of 4 and for therapeutic diets it averaged 1.9 out of 3. To reform the health insurance coverage system for patient meals, it is urgent that the qualified level of patient meals is presented from a national viewpoint, and monitoring should be performed consistently by developing the evaluation tools.