• Korean Journal of Remote Sensing
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• v.39 no.6_2
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• pp.1565-1576
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• 2023

An atmospheric correction algorithm based on the radiative transfer model is required to obtain remote-sensing reflectance (R_rs) from the Geostationary Ocean Color Imager-II (GOCI-II) observed at the top-of-atmosphere. This R_rs derived from the atmospheric correction is utilized to estimate various marine environmental parameters such as chlorophyll-a concentration, total suspended materials concentration, and absorption of dissolved organic matter. Therefore, an atmospheric correction is a fundamental algorithm as it significantly impacts the reliability of all other color products. However, in clear waters, for example, atmospheric path radiance exceeds more than ten times higher than the water-leaving radiance in the blue wavelengths. This implies atmospheric correction is a highly error-sensitive process with a 1% error in estimating atmospheric radiance in the atmospheric correction process can cause more than 10% errors. Therefore, the quality assessment of R_rs after the atmospheric correction is essential for ensuring reliable ocean environment analysis using ocean color satellite data. In this study, a Quality Assurance (QA) algorithm based on in-situ R_rs data, which has been archived into a database using Sea-viewing Wide Field-of-view Sensor (SeaWiFS) Bio-optical Archive and Storage System (SeaBASS), was applied and modified to consider the different spectral characteristics of GOCI-II. This method is officially employed in the National Oceanic and Atmospheric Administration (NOAA)'s ocean color satellite data processing system. It provides quality analysis scores for R_rs ranging from 0 to 1 and classifies the water types into 23 categories. When the QA algorithm is applied to the initial phase of GOCI-II data with less calibration, it shows the highest frequency at a relatively low score of 0.625. However, when the algorithm is applied to the improved GOCI-II atmospheric correction results with updated calibrations, it shows the highest frequency at a higher score of 0.875 compared to the previous results. The water types analysis using the QA algorithm indicated that parts of the East Sea, South Sea, and the Northwest Pacific Ocean are primarily characterized as relatively clear case-I waters, while the coastal areas of the Yellow Sea and the East China Sea are mainly classified as highly turbid case-II waters. We expect that the QA algorithm will support GOCI-II users in terms of not only statistically identifying R_rs resulted with significant errors but also more reliable calibration with quality assured data. The algorithm will be included in the level-2 flag data provided with GOCI-II atmospheric correction.

• Journal of Korean Society for Atmospheric Environment
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• v.29 no.4
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• pp.439-446
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• 2013

In this research, the present standard analytical methods for the monitoring of air pollution levels established by the Korean Ministry of Environment (KMOE) were examined in reference to the recent outputs of several research projects conducted for their amendments. The evaluation of the two criterion methods between the main (the present guideline) and reference methods (the proposed alternate guideline) was made in terms of authenticity and reliability of the quality assurance (QA) and of compatibility of methods. The results of this comparative evaluation are presented for the analysis of both ambient air and source samples. Based on this analysis, we propose a new direction for the future amendment.

• Quality Improvement in Health Care
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• v.28 no.2
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• pp.30-38
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• 2022

Purpose: The Health Insurance Review and Assessment Service (HIRA) in South Korea initiated a quality assessment (QA) program for blood transfusion healthcare services in 2020 to ensure patient safety and appropriate blood use. This study examines the quality of blood transfusion services since the first national QA program for blood transfusion services in Korea. Methods: We analyzed HIRA claims and QA investigation data based on inpatient medical records from all tertiary, general, and primary hospitals between October 2020 and March 2021. The target population was patients aged 18 years and older who received either total knee arthroplasty or red blood cell transfusion. The QA indicators for transfusion healthcare service consisted of four quality indicators and four monitoring indicators. Results: We analyzed the results of QA indicators for transfusion service from the medical records of 189,668 patients from 1,171hospitals and expressed indicators as proportions. The average results for evaluation indicators were as follows: transfusion checklist presence, 64.8%; irregular antibody tests, 61.8%; transfusions in which the hemoglobin levels before transfusion met the transfusion guidelines for patients undergoing total knee arthroplasty, 20.6%, and transfusions in patients undergoing total knee arthroplasty, 59.3%. The average results for monitoring indicators were as follows: transfusion management implementation in medical institutions, 56.9%; preoperative anemia management in anemia patients undergoing total knee arthroplasty, 43.9%; one-unit transfusions, 82.5%; and the transfusion index. Conclusion: The quality of blood transfusion healthcare varied and the assessment revealed that there is scope for improvement. Hospitals require more effective blood transfusion management and this can be facilitated by providing feedback on the QA results about blood transfusion healthcare services to medical institutions, and by disclosing the results to the public.

• Journal of the Korean Society of Radiology
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• v.7 no.5
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• pp.339-345
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• 2013

In foreign countries, the impotance of quality assurance (QA) is increasing, whereas QA evaluation standards are not established properly in Korea. Thus this study was conducted to suggest improved QA evaluation standards and methods by studying/comparing/analyzing the literature in both Korea and foreign countries and prove its suitability through simulated evaluation. result of research in south korea, much check list using the evaluation method subjective, the evaluation of accuracy and reproducibility is meausred in the number of missing. Therefore, attempts to present a clear reference evaluation and objective way to solve the problem, examined the accuracy and reproducibility and 10times of measurement. The results of the simulated evaluation satisfied both proposed evaluation standards and methods. However the QA evaluation standards and methods for the items that are implemented only in Korea and high-contrast spatial resolution could have been established. In this regard, there is a need of further studies on the establishment of QA evaluation standards and methods that suits Korean situation.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2011.10a
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• pp.547-550
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• 2011

We measured that is Gantry, Collimator Star Shot, Light vs. Radiation, HDR QA with Medical LINAC Then, PACS was implemented on the digital images on the monitor that can be confirmed through the QA. Also, for cooperation with OCS system that is using from present source and impose code that need in treatment in each treatment, did so that Order that connect to network, input to CR may appear, did so that can solve support data mistake of Pinacle and PACS that is Planning System and look at Planning premier in PACS.

• Journal of radiological science and technology
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• v.46 no.3
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• pp.231-238
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• 2023

This study aimed to compare the results of delivery quality assurance (DQA) using MapCHECK and OCTAVIUS for radiation therapy. Thirty patients who passed the DQA results were retrospectively included in this study. The point dose difference (DD) and gamma passing rate (GPR) were analyzed to evaluate the agreement between the measured and planned data for all cases, Plan complexity was evaluated to analyze dosimetric accuracy by quantifying the degree of modulation according to each plan. We analyzed the monitor units (MUs) and total MUs for each plan to evaluate the correlation between the MUs and plan complexity. We used a paired t-test to compare the DD and GPRs that were obtained using the two devices. The DDs and GPRs were within the tolerance range for all cases. The average GPRs difference between the two devices was statistically significant for the brain, and head and neck for gamma criteria of 3%/3 mm and 2%/2 mm. There was no significant correlation between the modulation index and total MUs for any of the cases. These DQA devices can be used interchangeably for routine patient-specific QA in radiation therapy.

• Progress in Medical Physics
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• v.32 no.4
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• pp.122-129
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• 2021

Purpose: This study aimed to design a multipurpose dose verification phantom for external audits to secure safe and optimal radiation therapy. Methods: In this study, we used International Atomic Energy Agency (IAEA) LiF powder thermoluminescence dosimeter (TLD), which is generally used in the therapeutic radiation dose assurance project. The newly designed multipurpose phantom (MPP) consists of a container filled with water, a TLD holder, and two water-pressing covers. The size of the phantom was designed to be sufficient (30×30×30 cm³). The water container was filled with water and pressed with the cover for normal incidence to be fixed. The surface of the MPP was devised to maintain the same distance from the source at all times, even in the case of oblique incidence regardless of the water level. The MPP was irradiated with 6, 10, and 15 MV photon beams from Varian Linear Accelerator and measured by a 1.25 cm³ ionization chamber to get the correction factors. Monte Carlo (MC) simulation was also used to compare the measurements. Results: The result obtained by MC had a relatively high uncertainty of 1% at the dosimetry point, but it showed a correction factor value of 1.3% at the 5 cm point. The energy dependence was large at 6 MV and small at 15 MV. Various dosimetric parameters for external audits can be performed within an hour. Conclusions: The results allow an objective comparison of the quality assurance (QA) of individual hospitals. Therefore, this can be employed for external audits or QA systems in radiation therapy institutions.

• Proceedings of the Korean Society of Medical Physics Conference
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• 2006.08a
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• pp.101-101
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• 2006

• Progress in Medical Physics
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• v.23 no.1
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• pp.33-41
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• 2012

For applying the quality assurance (QA) of volumetric modulated arc therapy (VMAT) introduced in Eulji Hospital, we classify it into three different QA steps, treatment planning QA, pretreatment delivering QA, and treatment verifying QA. These steps are based on the existing intensity modulated radiation therapy (IMRT) QA that is currently used in our hospital. In each QA step, the evaluated items that are from QA program are configured and documented. In this study, QA program is not only applied to actual patient treatment, but also evaluated to establish a reference of clinical acceptance in pretreatment delivering QA. As a result, the confidence limits (CLs) in the measurements for the high-dose and low-dose regions are similar to the conventional IMRT level, and the clinical acceptance references in our hospital are determined to be 3 to 5% for the high-dose and the low-dose regions, respectively. Due to the characteristics of VMAT, evaluation of the intensity map was carried out using an ArcCheck device that was able to measure the intensity map in all directions, $360^{\circ}$. With a couple of dosimetric devices, the gamma index was evaluated and analyzed. The results were similar to the result of individual intensity maps in IMRT. Mapcheck, which is a 2-dimensional (2D) array device, was used to display the isodose distributions and gave very excellent local CL results. Thus, in our hospital, the acceptance references used in practical clinical application for the intensity maps of $360^{\circ}$ directions and the coronal isodose distributions were determined to be 93% and 95%, respectively. To reduce arbitrary uncertainties and system errors, we had to evaluate the local CLs by using a phantom and to cooperate with multiple organizations to participate in this evaluation. In addition, we had to evaluate the local CLs by dividing them into different sections about the patient treatment points in practical clinics.

• Journal of Integrative Natural Science
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• v.8 no.2
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• pp.128-134
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• 2015

This paper focuses on the applicability of a continuous monitoring method on trace sulfur compounds in the ambient air by TD and GC/PFPD. The target compounds for monitoring include H2S(hydrogen sulfide), Methyl mercaptan, Dimethyl Sulfide, and Dimethyl disulfide. The result of QA/QC on monitoring instruments satisfies all the standards of Odor Measurement and Analysis Method, showing that the reproductivity of the compounds by concentration is within 10%, linearity is above 0.98 of a correlation efficient, method detection limit is 0.16 ppb by MM standard, and recovery rate is over 70%. Monitoring was conducted for two years from March 2006 to February 2008. As a result of the monitoring, the average concentration of H2S was 0.08 ppb, with the maximum concentration at 16.15 ppb. The result indicates that it is reasonable to do continuous monitoring as there appears a spontaneous event of high concentration by the condition of the site during monitoring odor-causing substances. Therefore, it is suggested that the continuous monitoring method used in this paper is appropriate to identify the characteristics of sudden occurrence and concentration variations of sulfur compounds.