• Journal of Radiation Protection and Research
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• 제29권1호
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• pp.57-63
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• 2004

원자력발전소 가동중 검사의 일부로서 계획예방정비 기간중 수행되는 ECT 검사작업은 작업자의 과피폭 우려로 인해 방사선안전관리 대상으로 비중을 두고 관리감독이 이루어지고 있다. 정기적으로 반복되는 검사수행경험 사례 분석의 결과, ECT 검사작업 완료후 피폭결과가 방사선안전관리 목표선량을 상회하는 경우가 상당수 나타나고 있어서 개인별 피폭선량관리가 쉽지않고 방사선작업허가서 발급에도 지장을 초래하는 것으로 나타났다. 검사자의 피폭선량 저감을 위한 세심한 방사선작업계획 수립과 최적화된 방사선방호대책마련을 위한 지속적인 방사선작업 관련 자료 축적도 중요하다고 판단되나, ECT검사 방사선작업계획의 기본요소인 작업내용 및 작업소요시간, 작업인원에 대한 검토와 논의는 미미한 실정이다. 방사선작업계획 수립의 근간을 이루는 예상피폭선량표에 포함될 검사작업내용과 검사자 작업소요시간에 대하여 반복시험과 사례분석 결과를 제시하였다.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1997년도 한국자동제어학술회의논문집; 한국전력공사 서울연수원; 17-18 Oct. 1997
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• pp.1884-1887
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• 1997

The increasing concern over radiation exposure in the nuclear industry has fostered agrressive efforts to reduce the levels of radiation exposure. One area of the effot to reduce the radiation exposure is the development of a remote radiation monitoring system. Remote radiation monitoring can serve many benificaial functions reduce exposure to radiation by plant personnel, impruve the quality of the data that is collected and recognize the radiation environment easily. Radiation mapping system gives a good information that represents radiation level distribution. The system we have developed consists of a data acquistion parts, mobile robot and remote control parts. Data acquisition parts consist of radiation detection module and vision acquistion module which collect radiation data, visiion data and distance information. In remote control parts, the acquision data are processed and displayed. We have constructed radiation mapping image by overlaying the vision and radiation data. The radiation mapping techniques for displaying the results of the survey in an easily comprehendable form will facilitate a better understanding of the radiation environment in the facility. This system can reduce workers radiation exposure and aid to help work plan, so it has significant benifits in cost and safety.

• 한국의학물리학회:학술대회논문집
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• 한국의학물리학회 2002년도 Proceedings
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• pp.83-85
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• 2002

Yonsei Cancer Center introduced an IMRT System at the beginning of February, 2002. The system consists of CORVUS(NOMOS) inverse planning machine, LANTIS(SIEMENS), PRIMEVIEW and PRIMART Linac(SIEMENS). The optimization of CORVUS planning system with PRIMART is an important work to get an efficient treatment plan. So, we studied two Finite Size Pencil Beams, 1.0 x 1.0 cm$^2$ and 0.5 x 1.0 cm$^2$, and four leaf transmission sets, 5%, 10%, 20%, 33%. We compared the dose distribution of target volume and delivery efficiency of the plan results.

• Journal of Radiation Protection and Research
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• 제44권1호
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• pp.32-42
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• 2019

Background: There have been much efforts to develop the proper and realistic machine Quality Assurance (QA) reflecting on real Volumetric Modulated Arc Therapy (VMAT) plan. In this work we propose and test a special VMAT plan of plan-class specific (pcsr) QA, as a machine QA so that it might be a good solution to supplement weak point of present machine QA to make it more realistic for VMAT treatment. Materials and Methods: We divided human body into 5 treatment sites: brain, head and neck, chest, abdomen, and pelvis. One plan for each treatment site was selected from real VMAT cases and contours were mapped into the computational human phantom where the same plan as real VMAT plan was created and called plan-class specific reference (pcsr) QA plan. We delivered this pcsr QA plan on a daily basis over the full research period and tracked how much MLC movement and dosimetric error occurred in regular delivery. Several real patients under treatments were also tracked to test the usefulness of pcsr QA through comparisons between them. We used dynalog file viewer (DFV) and Dynalog file to analyze position and speed of individual MLC leaf. The gamma pass rate from portal dosimetry for different gamma criteria was analyzed to evaluate analyze dosimetric accuracy. Results and Discussion: The maxRMS of MLC position error for all plans were all within the tolerance limit of < 0.35 cm and the positional variation of maxPEs for both pcsr and real plans were observed very stable over the research session. Daily variations of maxRMS of MLC speed error and gamma pass rate for real VMAT plans were observed very comparable to those in their pcsr plans in good acceptable fluctuation. Conclusion: We believe that the newly proposed pcsr QA would be useful and helpful to predict the mid-term quality of real VMAT treatment delivery.

• 한국의학물리학회지:의학물리
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• 제28권3호
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• pp.122-128
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• 2017

Eclipse Scripting Application Programming Interface (ESAPI) was devised to enhance the efficiency in such treatment related workflows as contouring, treatment planning, plan quality measure, and data-mining by communicating with the treatment planning system (TPS). It is provided in the form of C# programming based toolbox, which could be modified to fit into the clinical applications. The Scripting program, however, does not offer all potential functionalities that the users intend to develop. The shortcomings can be overcome by combining the Scripting programming with user-executable program on Windows or Linux. The executed program has greater freedom in implementation, which could strengthen the ability and availability of the Scripting on the clinical applications. This work shows the use of the Scripting programming throughout the simple modification of the given toolbox. Besides, it presents the implementation of combining both Scripting and user-executed programming based on MATLAB, applied to automated dynamic MLC wedge and FIF treatment planning procedure for promoting the planning efficiency.

• 한국산업보건학회지
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• 제25권1호
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• pp.27-35
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• 2015

Objectives: To investigate safety and health management, conditions in factories or facilities handling radiation-generating devices and radioactive isotopes were reviewed in terms of regulations of radiation safety control in Korea. Radiation exposure levels generated at those facilities were directly measured and evaluated for establishing an effective safety and health management plan. Methods: Government organizations with laws and systems of radiation safety and health were investigated and compared. There are three laws governing radiation-related employment such as occupational safety and health acts, nuclear safety acts, and medical service acts. We inspected 12 workplaces as research objects:four workplaces that manufacture and assemble semiconductor devices, three non-destructive inspection workplaces that perform inspections on radiation penetration, and five workplaces in textile and tire manufacturing. Monitoring of radiation exposure was performed through two methods. Spatial and surface monitoring using real-time radiation instruments was performed on each site handling radiation generating devices and radioactive isotopes in order to identify radiation leakage. Results: According to the occupational safety and health act, there is no legal obligation to measure ionizing radiation and set dose limits. This can cause confusion in the application of the laws, because the scopes and contents are different from each other. Surface dose rates in radiation generating devices such as implanters, thickness gages and accelerators, which were registered according to nuclear safety acts, using surveymeters, and seven of 36 facilities(19.4%) exceeded the international standards for surface radiation dose of $10{\mu}Sv/hr$. Conclusions: The results showed that occupational health and safety acts require a separate provision for measuring and assessing the radiation exposure of workers performing radiation work. Like noise, ionizing radiation will also periodically be controlled by including it in the object factors of work-environment measurement.

• Journal of the Korean Physical Society
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• 제80권
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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.

• 방사선산업학회지
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• 제17권3호
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• pp.265-273
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• 2023

To effectively and safely manage the radiation exposure to nuclear power plant (NPP) workers in accidents, major overseas NPP operators such as the United States, Germany, and France have developed and applied realistic 3D model radiation dose assessment software for workers. Continuous research and development have recently been conducted, such as performing NPP accident management using 3D-VR based on As Low As Reasonably Achievable (ALARA) planning tool. In line with this global trend, it is also required to secure technology to manage radiation exposure of workers in Korea efficiently. Therefore, in this paper, it is described the application method and assessment results of radiation exposure scenarios for workers in response to accidents assessment technology, which is one of the fundamental technologies for constructing a realistic platform to be utilized for radiation exposure prediction, diagnosis, management, and training simulations following accidents. First, the post-accident sampling after the Loss of Coolant Accident(LOCA) was selected as the accident and response scenario, and the assessment area related to this work was established. Subsequently, the structures within the assessment area were modeled using MCNP, and the radiation source of the equipment was inputted. Based on this, the radiation dose distribution in the assessment area was assessed. Afterward, considering the three principles of external radiation protection (time, distance, and shielding) detailed work scenarios were developed by varying the number of workers, the presence or absence of a shield, and the location of the shield. The radiation exposure doses received by workers were compared and analyzed for each scenario, and based on the results, the optimal accident response scenario was derived. The results of this study plan to be utilized as a fundamental technology to ensure the safety of workers through simulations targeting various reactor types and accident response scenarios in the future. Furthermore, it is expected to secure the possibility of developing a data-based ALARA decision support system for predicting radiation exposure dose at NPP sites.

• 방사선산업학회지
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• 제18권4호
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• pp.307-325
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• 2024

The Second High Level Radioactive Waste Management Basic Plan for Dry Interim Storage and Interim Storage of Spent Nuclear Fuel has been released. The Dual Purpose Canister (DPC) has emerged as a way to avoid repeating the mistakes made by leading countries in spent fuel management by not considering the linkages between management steps. From the worker's point of view, the dose is likely to be influenced by the operating procedures and work patterns of the dry storage facility. It is necessary to conduct a survey on the operating procedures and work patterns of each dry storage method before evaluating the exposure dose. The purpose of this study is to investigate and analyze the work procedures and work patterns of commercially available DPC-based spent fuel dry storage facilities in other countries. For this purpose, the dry storage systems commercialized overseas were first categorized into 1) concrete overpack, 2) vertical storage module, and 3) metal overpack. The HI-STORM 100, NAC-UMS, VSC-24, and Fuel Solutions systems were selected as the subjects of the study for the concrete overpack method. The HI-STORM UMAX system was selected for the vertical storage module method, and the HI-STAR 100 system was selected for the metal overpack method. To analyze the operating procedures and work patterns, the loading and unloading procedures described in the Final Safety Analysis Report (FSAR) for each system were analyzed, as well as the time and personnel required for each task. The results showed that, on average, the loading procedure requires 13.4 more steps and 644.5 more minute than the unloading procedure, although there are detailed differences in operating procedures and work patterns among dry storage systems. The results of this study can be used as a basis for the radiological impact assessment of workers during the operation of spent fuel dry storage facilities.

• 한국의학물리학회지:의학물리
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• 제21권3호
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• pp.304-310
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• 2010

현재 이용되고 있는 상용 치료 계획시스템은 대부분의 치료용 선형가속기가 제공하는 전자선 회전 방식의 치료 기능을 제공하지 않고 있으며, 이것은 전자선 회전 치료가 널리 이용되지 못하는 한 가지 원인이 되기도 한다. 본 연구에서는 Varian 21-EX에 대해, pencil beam 기반의 Pinnacle3 (ver. 7.4f)를 이용한 전자선 회전 치료를 위한 커미셔닝을 한 후, 치료 계획을 세웠으며, 그 정확도를 평가해 보았다. 회전 빔은 폭이 일정한 조사빔을 규칙적으로 반복해서 구현하였으며, 필름과 점 선량을 측정하였다. 치료계획 시스템의 모델링 단계에서, 측정된 깊이 선량분포는 모델링의 계산과 1% 내에서 일치하였으나, 가로 선량분포의 경우에는 모델링 계산이 측정보다 작아서, 50% 선량값을 기준으로 할 때, 6 MeV는 distance-to-agreement (DTA) 값이 5.1 mm, 12 MeV의 경우에는 6.7 mm이었다. 인체모형 팬텀을 대상으로한 점 선량 및 필름 측정의 경우, 계산과 측정은 10% 이상의 차이를 보였다. Pencil beam 기반의 전자선 회전 치료 계획은 정량적인 기준으로 삼기에는 부족해서 선량 분포에 대한 정성적인 참고에만 머물러야 하며, 환자 치료 전에 측정을 통해 선량 확인이 필요하다.