• Journal of the Korean Society of Radiology
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• v.18 no.3
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• pp.283-292
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• 2024

Radiation side effects and complications on the ocular adnexa during electron beam therapy for orbital lymphoma can increase the incidence of posterior subcapsular cataracts. This study simulated a medical linear accelerator and a mathematical model of the eye using monte carlo simulations to evaluate the dose to the ocular adnexa and compare the shielding effectiveness on different parts of the ocular adnexa based on lens shield thickness. The dose assessment results of the ocular adnexa showed that the lens's sensitive area had the highest absorbed dose distribution when no shield was used, followed by the lens's non-sensitive area, the anterior chamber, vitreous humor, cornea, and eyelid in descending order. With the use of a shield, a 2 mm thick shield demonstrated a dose reduction effect of over 90% in the lens's sensitive area, over 83% in the non-sensitive area and anterior chamber, and a dose reduction effect of 30 to 62% in the vitreous body, cornea, and eyelid. For dose reduction in the lens's sensitive area during electron beam therapy for orbital lymphoma, it is necessary to use a shield of at least 2 mm thickness. Additionally, shielding strategies considering the thickness and area of the shield for other ocular adnexa besides the lens are required.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.18 no.spc
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• pp.75-87
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• 2020

The Korea Atomic Energy Research Institute (KAERI) has developed geological repository systems for the disposal of high-level wastes and spent nuclear fuels (SNFs) in South Korea. The purpose of the most recently developed system, the improved KAERI Reference Disposal System Plus (KRS⁺), is to dispose of all SNFs in Korea with improved disposal area efficiency. In this paper, a system-level safety assessment model for the KRS⁺ is presented with long-term assessment results. A system-level model is used to evaluate the overall performance of the disposal system rather than simulating a single component. Because a repository site in Korea has yet to be selected, a conceptual model is used to describe the proposed disposal system. Some uncertain parameters are incorporated into the model for the future site selection process. These parameters include options for a fractured pathway in a geosphere, parameters for radionuclide migration, and repository design dimensions. Two types of SNF, PULS7 from a pressurized water reactor and Canada Deuterium Uranium from a heavy water reactor, were selected as a reference inventory considering the future cumulative stock of SNFs in Korea. The highest peak radiological dose to a representative public was estimated to be 8.19×10^-4 mSv·yr^-1, primarily from ¹²⁹I. The proposed KRS⁺ design is expected to have a high safety margin that is on the order of two times lower than the dose limit criterion of 0.1 mSv·yr^-1.

• Journal of Preventive Medicine and Public Health
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• v.43 no.3
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• pp.245-256
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• 2010

Objectives: This study aims to compare quality indicators for the hemodialysis services between patients with health insurance and those with medical aid. Methods: This study used data from sampled hospitals that provided a hemodialysis service. A total of 2287 patients were selected, and the information for hemodialysis service has been granted from medical record reviews. A multi-level regression analysis was used to examine the differences in process and outcome indicators for hemodialysis between patients with health insurance and those with medical aid. Process indicators were defined as: frequency of hemodialysis, hemodialysis time, erythropoietin (EPO) use, measurement of hemodialysis dose at least once a month, measurement of phosphate at least once every three months, and measurement of albumin at least once every three months. Outcome indicators were defined as: hemodialysis adequacy, anemia management, blood pressure management, and calcium, phosphate and nutrition management. The total scores for outcome indicators ranged from 0 (worst) to 4 (best). Results: There was a significant difference in the measurement of hemodialysis dose at least once a month between patients with health insurance and those with medical aid (OR 0.66, 95% CI = 0.43 - 0.99). However, frequency of hemodialysis, hemodialysis time, EPO use, measurement of phosphate at least once every three months, measurement of albumin at least once every three months, hemodialysis adequacy management, Hb${\geq}$11 g/dL, blood pressure within the range of 100-140 /60-90 mmHg, calcium x phosphate${\leq}$55 $g^2/dL^2$ and albumin${\geq}$4 g/dL were not significantly different between the groups. Conclusions: There were no significant differences in outcome indicators for hemodialysis between the groups. Further studies are warranted into the mechanism that results in no differences in the outcome indicators for hemodialysis.

• Journal of the Korean Medical Association
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• v.61 no.11
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• pp.687-698
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• 2018

Inappropriate antibiotic use significantly contributes to antibiotic resistance, resulting in reduced antibiotic efficacy and an increased burden of disease. The objective of this study was to investigate the characteristics of prescribers whose antibiotics use was high and to explore factors affecting the use of antibiotics by medical institutions. This study analyzed the National Health Insurance claims data from 2015. Antibiotic prescription data were analyzed in terms of the number of defined daily doses per 1,000 patients per day, according to the World Health Organization anatomical-therapeutic-chemical classification and methodologies for measuring the defined daily dose. We investigated the characteristics of prescribers and medical institutions with high antibiotic use. Multivariate regression analyses were performed on the basis of characteristics of the medical institution (number of patients, type of medical institution [hospital or clinic], age of the physician, etc.). The number of patients and number of beds were found to be significant factors affecting antibiotic use in hospitals, and the number of patients, region, and medical department were significant factors affecting antibiotic use at the level of medical institutions. These findings are expected to help policy-makers to better target future interventions to promote prudent antibiotic prescription.

• Korean Journal of Clinical Pharmacy
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• v.34 no.2
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• pp.134-139
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• 2024

Background: Increasing numbers of studies and research about artificial intelligence (AI) and machine learning (ML) have led to their application in clinical trials. The purpose of this study is to analyze computer-based new technologies (AI/ML) applied on clinical trials registered on ClinicalTrials.gov to elucidate current usage of these technologies. Methods: As of March 1st, 2023, protocols listed on ClinicalTrials.gov that claimed to use AI/ML and included at least one of the following interventions-Drug, Biological, Dietary Supplement, or Combination Product-were selected. The selected protocols were classified according to their context of use: 1) drug discovery; 2) toxicity prediction; 3) enrichment; 4) risk stratification/management; 5) dose selection/optimization; 6) adherence; 7) synthetic control; 8) endpoint assessment; 9) postmarketing surveillance; and 10) drug selection. Results: The applications of AI/ML were explored in 131 clinical trial protocols. The areas where AI/ML was most frequently utilized in clinical trials included endpoint assessment (n=80), followed by dose selection/optimization (n=15), risk stratification/management (n=13), drug discovery (n=4), adherence (n=4), drug selection (n=1) and enrichment (n=1). Conclusion: The most frequent application of AI/ML in clinical trials is in the fields of endpoint assessment, where the utilization is primarily focuses on the diagnosis of disease by imaging or video analyses. The number of clinical trials using artificial intelligence will increase as the technology continues to develop rapidly, making it necessary for regulatory associates to establish proper regulations for these clinical trials.

• Journal of Radiation Protection and Research
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• v.35 no.4
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• pp.163-166
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• 2010

The effective dose of the Seoul subway staffs due to inhaled radon ($^{222}Rn$) in their workplace was investigated depended on radon concentration exposed at each workplace, and working hours and working types of the staffs. Annual average radon concentrations ranged from 16.5 to 93.0 $Bq{\cdot}m^{-3}$. The staffs commonly spend 2,304 hours in the underground spaces a year. With the radon concentrations and the working hours of the staffs, estimated annual effective doses ranged from 0.23 to 0.73 $mSv{\cdot}y^{-1}$.

• Nuclear Engineering and Technology
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• v.30 no.5
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• pp.444-451
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• 1998

The cost-effective reduction of occupational radiation exposure (ORE) dose at a nuclear power plant could not be achieved without going through an extensive analysis of accumulated ORE dose data of existing plants. It is necessary to identify what are high ORE jobs for ALARA implementation. In this study, the Rank Sum Method (RSM) is used in identifying high ORE jobs. As a case study, the database of ORE-related maintenance and repair jobs for Kori Units 3 and 4 is used for assessment, and top twenty high ORE jobs are identified. The results are also verified and validated using the Friedman test, and RSM is found to be a very efficient way of analyzing the data.

• Proceedings of the Korean Society of Toxicology Conference
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• 2002.11b
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• pp.171-171
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• 2002

This study was carried out by an Korean GLP laboratory to assess the combined repeated dose, reproduction and developmental toxicity of benzoyl peroxide for OECD SIDS(Screening Information Data Set) program. Male and female Sprague Dawley rats were exposed to benzoyl peroxide at levels of 0, 250, 500 and 1,000 mg/kg/day for 29 days for male and for 41-51 days for female.(omitted)

• Nuclear Engineering and Technology
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• v.53 no.6
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• pp.2019-2024
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• 2021

For evaluating the radiological safety of dismantled concrete, the process of disposal and recycling of the radioactive concrete generated during the dismantling of Kori Unit 1 is analyzed. Four scenarios are derived based on the analysis of the concrete recycling and disposal process, and the potential exposure to the workers and public during this process are calculated. VISIPLAN and RESRAD code are used for evaluating the dosages received by the workers and public in the following four scenarios: concrete inspection, transport of concrete by the truck driver, driving on a recycled concrete road, and public living near the landfilled concrete waste. Two worker exposure scenarios in the processing of concrete and two public exposure scenarios in recycling and disposal are considered; in all the scenarios, the exposure dose does not exceed the annual dose limit for each representative.

• Communications for Statistical Applications and Methods
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• v.29 no.2
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• pp.239-250
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• 2022

In many applications, we frequently encounter correlated multiple outcomes measured on the same subject. Joint modeling of such multiple outcomes can improve efficiency of inference compared to independent modeling. For instance, in developmental toxicity studies, fetal weight and number of malformed pups are measured on the pregnant dams exposed to different levels of a toxic substance, in which the association between such outcomes should be taken into account in the model. The number of malformations may possibly have many zeros, which should be analyzed via zero-inflated count models. Motivated by applications in developmental toxicity studies, we propose a Bayesian joint modeling framework for continuous and count outcomes with excess zeros. In our model, zero-inflated Poisson (ZIP) regression model would be used to describe count data, and a subject-specific random effects would account for the correlation across the two outcomes. We implement a Bayesian approach using MCMC procedure with data augmentation method and adaptive rejection sampling. We apply our proposed model to dose-response analysis in a developmental toxicity study to estimate the benchmark dose in a risk assessment.