• Title/Summary/Keyword: QA System

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Real Time On-line Quality Assurance System for HDR Brachytherapy (고선량률 근접 방사선 치료를 위한 실시간 온-라인 정도 관리(QA) 시스템 개발)

  • Lee Su Jin;Lee Re Na;Yi Byang Yang;Lim Sang Waak;Choi Jin Ho
    • 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.

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C1qa deficiency in mice increases susceptibility to mouse hepatitis virus A59 infection

  • Kim, Han-Woong;Seo, Sun-Min;Kim, Jun-Young;Lee, Jae Hoon;Lee, Han-Woong;Choi, Yang-Kyu
    • Journal of Veterinary Science
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    • v.22 no.3
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    • pp.36.1-36.12
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    • 2021
  • Background: Mouse hepatitis virus (MHV) A59 is a highly infectious pathogen and starts in the respiratory tract and progresses to systemic infection in laboratory mice. The complement system is an important part of the host immune response to viral infection. It is not clear the role of the classical complement pathway in MHV infection. Objectives: The purpose of this study was to determine the importance of the classical pathway in coronavirus pathogenesis by comparing C1qa KO mice and wild-type mice. Methods: We generated a C1qa KO mouse using CRISPR/Cas9 technology and compared the susceptibility to MHV A59 infection between C1qa KO and wild-type mice. Histopathological and immunohistochemical changes, viral loads, and chemokine expressions in both mice were measured. Results: MHV A59-infected C1qa KO mice showed severe histopathological changes, such as hepatocellular necrosis and interstitial pneumonia, compared to MHV A59-infected wild-type mice. Virus copy numbers in the olfactory bulb, liver, and lungs of C1qa KO mice were significantly higher than those of wild-type mice. The increase in viral copy numbers in C1qa KO mice was consistent with the histopathologic changes in organs. These results indicate that C1qa deficiency enhances susceptibility to MHV A59 systemic infection in mice. In addition, this enhanced susceptibility effect is associated with dramatic elevations in spleen IFN-γ, MIP-1 α, and MCP-1 in C1qa KO mice. Conclusions: These data suggest that C1qa deficiency enhances susceptibility to MHV A59 systemic infection, and activation of the classical complement pathway may be important for protecting the host against MHV A59 infection.

Evaluation on the Accuracy of the PPS in the Proton Therapy System, Which Uses the Self Made QA Phantom (자체 제작한 QA Phantom을 이용한 양성자 PPS (Patient Positioning System)의 정확성 평가)

  • Lee, Ji-Eun;Kim, Jae-Won;Kang, Dong-Yoon;Choi, Jae-Hyeok;Yeom, Du-Seok
    • The Journal of Korean Society for Radiation Therapy
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    • v.24 no.2
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    • pp.115-121
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    • 2012
  • Purpose: The process of the proton treatment is done by comparing the DRR and DIPS anatomic structure to find the correction factor and use the PPS to use this factor in the treatment. For the accuracy of the patient set up, the PPS uses a 6 axis system to move. Therefore, there needs to be an evaluation for the accuracy between the PPS moving materialization and DIPS correction factor. In order to do this, we will use a self made PPS QA Phantom to measure the accuracy of the PPS. Materials and Methods: We set up a PPS QA Phantom at the center to which a lead marker is attached, which will act instead of the patient anatomic structure. We will use random values to create the 6 axis motions and move the PPS QA Phantom. Then we attain a DIPS image and compare with the DRR image in order to evaluate the accuracy of the correction factor. Results: The average correction factor, after moving the PPS QA Phantom's X, Y, Z axis coordinates together from 1~5 cm, 1 cm at a time, and coming back to the center, are 0.04 cm, 0.026 cm, 0.022 cm, $0.22^{\circ}$, $0.24^{\circ}$, $0^{\circ}$ on the PPS 6 axis. The average correction rate when moving the 6way movement coordinates all from 1 to 2 were 0.06 cm, 0.01 cm, 0.02 cm, $0.1^{\circ}$, $0.3^{\circ}$, $0^{\circ}$ when moved 1 and 0.02 cm, 0.04 cm, 0.01 cm, $0.3^{\circ}$, $0.5^{\circ}$, $0^{\circ}$ when moved 2. Conclusion: After evaluating the correction rates when they come back to the center, we could tell that the Lateral, Longitudinal, Vertical were all in the acceptable scope of 0.5 cm and Rotation, Pitch, Roll were all in the acceptable scope of $1^{\circ}$. Still, for a more accurate proton therapy treatment, we must try to further enhance the image of the DIPS matching system, and exercise regular QA on the equipment to reduce the current rate of mechanical errors.

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A new research program that aims to establish an external audit system to radiotherapy QA in Japan

  • Shimbo, Munefumi;Tabushi, Katsuyoshi;Endo, Masahiro;Ikeda, Hiroshi
    • Proceedings of the Korean Society of Medical Physics Conference
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    • 2002.09a
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    • pp.17-18
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    • 2002
  • Last year, a three-year research program was started in order to establish an external audit system to radiotherapy QA in Japan. It consists of questionnaire surveys, mailed (off-site) dosimetry and visited (on-site) dosimetry at radiotherapy facilities in Japan. The first questionnaire was sent to all Japanese radiotherapy facilities in October 2001, surveying basic QA procedures at each facility. 628 answers were returned with the return rate of 87%. In February 2002, the second questionnaire was sent. Off-site and on-site dosimetry have been tested in several facilities, and will be started soon. We anticipates that this program will gradually grow to a radiotherapy quality control center similar to Radiological Physics Center at MD Anderson Hospital.

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Computed Radiography applied to the Department of Radiation Oncology (Computed Radiography의 방사선종양학과로의 적용)

  • Hong, Seung-Il;Song, Jong-Nam;Kim, Young-Jae
    • 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.

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Performance Evaluation of Direct Broadcasting Satellite Channel using a MC and QA Method (MC기법과 QA기법을 이용한 직접위성방송채널 성능평가)

  • 정지원;조형래;고성찬
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.3 no.4
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    • pp.839-847
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    • 1999
  • This paper presents the performance evaluation of direct broadcasting satellite by monte-carlo(MC) and quasi-analytic(QA) simulation method in the existence of uplink/downlink adjacent channel interference(ACI), co-channel interference(CCI), and gaussian noise. Korea's satellite system parameters and link design are used at the simulation. MC and QA simulation methods are a valuable adjunct to analytical performance.

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Toward a Systemic Approach to Quality Assurance in e-Learning: An Ecological Perspective

  • JUNG, Insung
    • Educational Technology International
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    • v.11 no.2
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    • pp.25-41
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    • 2010
  • Challenges brought by applications of advanced technologies in education call for new approaches that can best ensure the provision of quality e-learning experiences. This paper presents an ecological approach as one of such approaches to quality assurance in e-learning that can monitor, assess and improve the effectiveness and the links between the various elements of e-learning. The ecological model for QA in e-learning emphasizes interrelation transactions between elements (e.g. providers, learners, cultures and policies) and systemic integration of those elements, and stresses that all these elements within a QA system play an equal role in maintaining balance of the whole. The model focuses attention both on individual and societal/cultural environmental factors as cornerstones for QA efforts in e-learning. It addresses the importance of QA efforts directed at changing QA transactions from provider-centered to 'all stakeholder-oriented', from one-size-fits-all model to 'globally oriented, locally adaptive model' and from control framework to 'culture creation framework'.

A Study on QA for Radiation Therapy Machine by Using Implemented Electronic Portal Imaging Device (전자포탈영상장치의 제작과 방사선치료장치의 QA 적용에 관한 연구)

  • Lee, Dong-Hoon
    • Journal of the Institute of Electronics Engineers of Korea SC
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    • v.43 no.6 s.312
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    • pp.68-75
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    • 2006
  • During cancer therapy by using high energy radiation, it is possible to improve the radiation therapy efficiency by performing a precise radiation therapy after verification of generated setup errors. In this paper, the video based electronic portal imaging device (EPID) which could display the portal image with near real time was developed to verify treatment position errors in radiation therapy instead of an analog typed portal film. This EPID system for applying QA tool of radiation therapy machine was consisted of a metal/fluorescent screen, $45^{\circ}$mirror, camera and image grabber. Radiation field verification has been performed to check quality assurance of the treatment machine itself by using this EPID system. The radiation field error was easily observed by edge detection of irradiated field size on EPID image when $0.6^{\circ}$ shift of collimator angle was generated. So, this implemented EPID system could be used as a radiation QA tool.

Development of Database and QA Systems for Post Closure Performance Assessment on A Potential HLW Repository

  • Hwang, Y-S;Kim, S-G;Kang, C-H
    • Nuclear Engineering and Technology
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    • v.34 no.4
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    • pp.406-414
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    • 2002
  • In TSPA of long-term post closure radiological safety on permanent disposal of HLW in Korea, appropriate management of input and output data through QA is necessary. The robust QA system is developed using the T2R3 principles applicable for five major steps in R&D's. The proposed system is implemented in the web-based system so that all participants in TSPA are able to access the system. In addition, the internet based input database for TSPA is developed. Currently data from literature surveys, domestic laboratory and field experiments as well as expert elicitation are applied for TSPA.

Quality Assurance of Patients for Intensity Modulated Radiation Therapy (세기조절방사선치료(IMRT) 환자의 QA)

  • Yoon Sang Min;Yi Byong Yong;Choi Eun Kyung;Kim Jong Hoon;Ahn Seung Do;Lee Sang-Wook
    • Radiation Oncology Journal
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    • v.20 no.1
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    • pp.81-90
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    • 2002
  • Purpose : To establish and verify the proper and the practical IMRT (Intensity--modulated radiation therapy) patient QA (Quality Assurance). Materials and Methods : An IMRT QA which consists of 3 steps and 16 items were designed and examined the validity of the program by applying to 9 patients, 12 IMRT cases of various sites. The three step OA program consists of RTP related QA, treatment information flow QA, and a treatment delivery QA procedure. The evaluation of organ constraints, the validity of the point dose, and the dose distribution are major issues in the RTP related QA procedure. The leaf sequence file generation, the evaluation of the MLC control file, the comparison of the dry run film, and the IMRT field simulate image were included in the treatment information flow procedure QA. The patient setup QA, the verification of the IMRT treatment fields to the patients, and the examination of the data in the Record & Verify system make up the treatment delivery QA procedure. Results : The point dose measurement results of 10 cases showed good agreement with the RTP calculation within $3\%$. One case showed more than a $3\%$ difference and the other case showed more than $5\%$, which was out side the tolerance level. We could not find any differences of more than 2 mm between the RTP leaf sequence and the dry run film. Film dosimetry and the dose distribution from the phantom plan showed the same tendency, but quantitative analysis was not possible because of the film dosimetry nature. No error had been found from the MLC control file and one mis-registration case was found before treatment. Conclusion : This study shows the usefulness and the necessity of the IMRT patient QA program. The whole procedure of this program should be peformed, especially by institutions that have just started to accumulate experience. But, the program is too complex and time consuming. Therefore, we propose practical and essential QA items for institutions in which the IMRT is performed as a routine procedure.