• Progress in Medical Physics
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• v.15 no.3
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• pp.156-160
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• 2004

An essential quality assurance (QA) procedure in high dose rate (HDR) remote after-loading brachytherapy is that of the verification of the Ir-192 HDR source positioning accuracy. A number of methods using mechanical rulers or autoradiograph and video cameras have been reported to check the positional error of the Ir-192 source. In this study, the feasibility of a CMOS (Complementary Metal Oxide Semiconductor) PC camera, with a fluorescent screen, was investigated. The agreement between the planned and measured dwell position was better than 1 mm and dwell times better than 0.4 sec. Our results indicate that the CMOS PC camera system could be used as a QA tool for the on-line determination of the source position and dwell time.

• Journal of the Korean Society of Radiology
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• v.8 no.3
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• pp.105-110
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• 2014

Diagnostic radiation equipment diagnosis and treatment of disease of recent plays a central role, but this is based on the assumption of an appropriate balance of benefits and risks of diagnostic. If balance is not maintained has the potential to give an adverse effect on the health of the public. In the case of an overseas, the importance of (QA) quality assurance of medical equipment is growing, but evaluation criteria of quality assurance has not been clearly presented in domestic. Therefore, the modernization of medical equipment from the point at which the degree of cycle-by-cycle management system of foreign national to be suitable for diagnostic radiation generator entry and quality control standards by introducing a tailoring is necessary. In this study the most frequently used diagnostic radiation generator X-ray imaging apparatus of the general three-year periodic inspections at any time between the periodic inspection items and quality control methods and standards for the establishment of the United States, Canada and abroad, and international electronic literature search Technical Committee (International Electro-technical Commission, IEC) were compared with the provisions of item. Based on the national quality control items when opening frequent inspection items and standards presented as a basis for setting up study.

• Journal of the Korean Society of Radiology
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• v.16 no.3
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• pp.211-216
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• 2022

In radiation therapy, accurate Quality Assurance (QA) is required to irradiate tumor tissue while minimizing damage to normal tissue. Therefore, a dosimeter that can accurately measure radiation is needed. The purpose of this study is to develop a highly efficient radiation dosimeter with high sensitivity by applying a particle in binder method that can reduce manufacturing costs and simplify processes to perovskite materials that are cheaper and simpler to manufacture. By evaluating the response characteristics to high-energy photon, the applicability of QA dosimeter to radiation therapy was evaluated. As a result of reproducibility evaluation, RSD at 6 MV energy was presented as 1.178% and 15 MV energy was presented as 1.141%. As a result of linearity evaluation according to linear regression analysis, R² values of 0.9999 were presented under each condition of 6 MV and 15 MV energy. It was found that the CsPbBr₃ dosimeter manufactured based on the results of reproducibility and linearity evaluation is highly applicable as a QA dosimeter in the field of therapeutic radiation. The CsPbBr₃ dosimeter manufactured in this study presented more than the standard performance in the evaluation of reproducibility and linearity, and it can be used as a radiotherapy QA dosimeter through improvement.

• Proceedings of the Korea Air Pollution Research Association Conference
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• 2002.04a
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• pp.143-144
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• 2002

본 연구는 대전 1,2 공단지역을 대상으로 22개의 금속원소를 ICP-MS를 이용하여 분석한 후, 이 농도 자료에 바탕하여 사용여지별 원소의 정밀도를 평가하고, 2 단계 선별과정을 통한 분석 농도의 대표성을 평가하고자 한다. (중략)

• The Journal of the Korea Contents Association
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• v.15 no.5
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• pp.436-443
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• 2015

The purpose of this study was to develop a self-diagnostic linearity quality control techniques of computed tomography (CT) by using measured CT number values from the various concentrations of iodine contrast media (CM) is diluted with distilled water under each condition of the tube voltage. The equipment was used for four-channel MDCT, the iodine concentration were using 300 mgI/ml, 350 mgI/ml, 370 mgI/ml and 400mgI/ml. Dilution of CM in distilled water was increased by each 5% until the maximum CT number values were measured. We applied the tube voltages for 90 kVp, 120 kVp, 140 kVp. As a result, we was obtained to the nearest linearity as 0.993 of correlation coefficient between the iodinated CM from 5% to 25% in 400 mgI/ml and the CT number values by 90 kVp. In conclusion, the proposed self-diagnostic linearity quality assurance technique by using iodine CM can be utilized to replace the AAPM CT performance phantom.

• The Journal of Korean Society for Radiation Therapy
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• v.35
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• pp.15-21
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• 2023

Purpose: The purpose of this study is to compare the performance of the anisotropic analytical algorithm (AAA) and portal dose image prediction (PDIP) for patient-specific quality assurance based on electronic portal imaging device, and to evaluate the clinical feasibility of portal dosimetry using AAA. Subjects and methods: We retrospectively selected a total of 32 patients, including 15 lung cancer patients and 17 liver cancer patients. Verification plans were generated using PDIP and AAA. We obtained gamma passing rates by comparing the calculated distribution with the measured distribution and obtained MLC positional difference values. Results: The mean gamma passing rate for lung cancer patients was 99.5% ± 1.1% for 3%/3 mm using PDIP and 90.6% ± 5.8% for 1%/1 mm. Using AAA, the mean gamma passing rate was 98.9% ± 1.7% for 3%/3 mm and 87.8% ± 5.2% for 1%/1 mm. The mean gamma passing rate for liver cancer patients was 99.9% ± 0.3% for 3%/3 mm using PDIP and 96.6% ± 4.6% for 1%/1 mm. Using AAA, the mean gamma passing rate was 99.6% ± 0.5% for 3%/3 mm and 89.5% ± 6.4% for 1%/1 mm. The MLC positional difference was small at 0.013 mm ± 0.002 mm and showed no correlation with the gamma passing rate. Conclusion: The AAA algorithm can be clinically used as a portal dosimetry calculation algorithm for patientspecific quality assurance based on electronic portal imaging device.

• Journal of radiological science and technology
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• v.44 no.4
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• pp.367-373
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• 2021

A quality assurance of computed tomography(CT) have done seven items that were water attenuation coefficient, noise, homogeneity, spatial resolution, contrast resolution, slice thickness, artifact using by standard phantom. But there is no quality assurance items and methods for CT simulator at domestic institutions yet. Therefore the study aimed to access the CT dose index(CTDI), table tilting, image distortion, laser accuracy, table movement accuracy and CT seven items for CT simulator quality assurance. The CTDI at the center of the head phantom was 0.81 for 80 kVp, 1.55 for 100 kVp, 2.50 for 120 mm, 0.22 for 80 kVp at the center of the body phantom, 0.469 for 100 kVp, and 0.81 for 120 kVp. The table tilting was within the tolerance range of ±1.0° or less. Image distortion had 1 mm distortion in the left and right images based on the center, and the laser accuracy was measured within ±2 mm tolerance. The purpose of this study is to improve the quality assurance items suitable for the current situation in Korea in order to protect the normal tissues during the radiation treatment process and manage the CT simulator that is implemented to find the location of the tumor more clearly. In order to improve the accuracy of the CT simulator when looking at the results, the error range of each item should be small. It is hoped that the quality assurance items of the CT simulator will be improved by suggesting the quality assurance direction of the CT simulator in this study, and the results of radiation therapy will also improve.

• The Korean Journal of Pesticide Science
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• v.15 no.4
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• pp.529-544
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• 2011

Many international organizations, such as the International Organization for Standardization (ISO) and Collaborative International Pesticide Analytical Council (CIPAC), have published a guide to quality control requirements, proficiency testing and method validation for pesticide formulation. In general, proficiency testing is to determine the performance of individual laboratories from the comparison of test results and to monitor a laboratory's performance abilities. One of quality assurance (QA) scheme would be include the validation of analytical method that implies a performance characteristics, specificity, selectivity, linearity and so on. According to many international organizations, the quantification methods of active substance in formulated pesticide products are required to be reproducible, accurate and precise. This study was conducted to compare the international guidelines for the quality control, proficiency testing and method validation of analytical laboratories and to propose a general guidance for the establishment of quality control system in the analytical chemistry laboratories of pesticide formulation in domestic.

• Nuclear Medicine and Molecular Imaging
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• v.42 no.4
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• pp.314-322
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• 2008

Purpose: It is widely recognized that good quality control (QC) program is essential for adequate imaging diagnosis using gamma camera. The purpose of this study is to survey the current status of QC of gamma cameras in Republic of Korea for implementing appropriate nationwide quality control guidelines and programs. Methods: A collection of data is done for personnel, equipment and appropriateness of each nuclear medicine imaging laboratory's quality control practice. This survey is done by collection of formatted questionnaire by mails, emails or interviews. We also reviewed the current recommendations concerning quality assurance by international societies. Results: This survey revealed that practice of quality control is irregular and not satisfactory. The irregularity of the QC practice seems due partly to the lack of trained personnel, equipment, budget, time and hand-on guidelines. Conclusion: The implementation of QC program may cause additional burden to the hospitals, patients and nuclear medicine laboratories. However, the benefit of a good QC program is obvious that the hospitals can provide good quality nuclear medicine imaging studies to the patients. It is important to use least cumbersome QC protocol, to educate the nuclear medicine and hospital administrative personnel concerning QC, and to establish national QC guidelines to help each individual nuclear medicine laboratory.

• Progress in Medical Physics
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• v.14 no.3
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• pp.151-160
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• 2003

The application of more complex radiotherapy techniques using multileaf collimation (MLC), such as 3D conformal radiation therapy and intensity-modulated radiation therapy (IMRT), has increased the significance of verifying leaf position and motion. Due to thier reliability and empirical robustness, quality assurance (QA) of MLC. However easy use and the ability to provide digital data of electronic portal imaging devices (EPIDs) have attracted attention to portal films as an alternatives to films for routine qualify assurance, despite concerns about their clinical feasibility, efficacy, and the cost to benefit ratio. In this study, we developed method for daily QA of MLC using electronic portal images (EPIs). EPID availability for routine QA was verified by comparing of the portal films, which were simultaneously obtained when radiation was delivered and known prescription input to MLC controller. Specially designed two-test patterns of dynamic MLC were applied for image acquisition. Quantitative off-line analysis using an edge detection algorithm enhanced the verification procedure as well as on-line qualitative visual assessment. In conclusion, the availability of EPI was enough for daily QA of MLC leaf position with the accuracy of portal films.