• Radiation Oncology Journal
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• v.3 no.1
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• pp.65-68
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• 1985

Primary lymphoid tumors of orbit are rare. Sometimes they pose difficulty in differentiating malignant non-Hodgkin's lymphoma of the orbit from benign lymphoid hyperplasia or pseudotumor of the orbit by growth characteristics and histologic examination of a biopsy specimen. Consequently, systemic work-up for staging of the disease before the initiation of treatment is essential. All lymphoid tumors of the orbit are radiosensitive and the response to radiotherapy is rapid and complete. Radiation dose for permanent control varies from 2,400 to 4,500rads in $2.5\~4$ weeks depending on extent and location of the disease. A case of localized lymphoma of the orbit was treated with radiotherapy. For the following 15 months, the patient was clinically free of disease without any evidence of side effects of radiation treatment.

• Nuclear Engineering and Technology
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• v.55 no.1
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• pp.285-294
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• 2023

Autonomous radiation source detection has long been studied for radiation emergencies. Compared to conventional data-driven or path planning methods, deep reinforcement learning shows a strong capacity in source detection while still lacking the generalized ability to the geometry in unknown environments. In this work, the detection task is decomposed into two subtasks: exploration and localization. A hierarchical control policy (HC) is proposed to perform the subtasks at different stages. The low-level controller learns how to execute the individual subtasks by deep reinforcement learning, and the high-level controller determines which subtasks should be executed at the current stage. In experimental tests under different geometrical conditions, HC achieves the best performance among the autonomous decision policies. The robustness and generalized ability of the hierarchy have been demonstrated.

• Nuclear Engineering and Technology
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• v.55 no.1
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• pp.373-377
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• 2023

The Monte Carlo (MC) method has become an indispensable part of the nuclear radiation research field. Several widely used and well-known MC packages were developed for simulation of radiation transport and interaction with matter. All these MC packages require users to prepare an input script. The input script can become lengthy for complex models. The process of preparing these input scripts is time-consuming and error-prone. In the present work, we have developed an open-source GUI computer program for modelling radiation transport and interaction in multi-segmented slab phantoms using grid-based system for the widely used PHITS MC package. The developed tools would be useful for future users of PHITS MC package and particularly inexperienced users. The present program is distributed under GPL license and all users can freely download, modify and redistribute the program without any restrictions.

• The Korean Journal of Nuclear Medicine Technology
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• v.21 no.2
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• pp.86-93
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• 2017

Purpose In this study, radiation workers who work in nuclear medicine department were analyzed to find the cause of differences of radiation exposure from General Characteristic, Knowledge, Recognition and Conduct, especially females working on nuclear medicine radiation, in order to pave the way for positive defense against radiation exposure. Materials and Methods The subjects were 106 radiation workers who were divided into two groups of sixty-four males and forty-two females answered questions about their General Characteristic, Knowledge, Recognition, Conduct, and radiation exposure dose which was measured by TLD (Thermo Luminescence Dosimeter). Results The results of the analysis revealed that as the higher score of knowledge and conduct was shown, the radiation exposure decreased in female groups, and as the higher score of conduct was shown, the radiation exposure decreased in male groups. In the correlation analysis of female groups, the non-experienced in pregnancy showed decreasing amount of radiation exposure as the score of knowledge and conduct was higher and the experienced in pregnancy showed decreasing amount of radiation exposure as the score of recognition and conduct was higher. In the regression analysis on related factors of radiation exposure dose of nuclear medicine radiation workers, the gender caused the meaningful result and the amount of radiation exposure of female groups compared to male groups. In the regression analysis on related factors of radiation exposure dose of female groups, the factor of conduct showed a meaningful result and the amount of radiation exposure of the experienced in pregnancy was lower compared to the non-experienced. Conclusion The conclusion of this study revealed that radiation exposure of female groups was lower than that of male groups. Therefore, male groups need to more actively defend themselves against radiation exposure. Among the female groups, the experienced in pregnancy who have an active defense tendency showed a lower radiation exposure. Thus, those who have never been pregnant need to have a more active defensive conduct for the future possibility of pregnancy.

• Nuclear Engineering and Technology
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• v.50 no.7
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• pp.1006-1016
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• 2018

Since the early forties, researchers from around the world have been studying the phenomenon of deadtime in radiation detectors. Many have attempted to develop models to represent this phenomenon. Two highly idealized models; paralyzable and non-paralyzable are commonly used by most individuals involved in radiation measurements. Most put little thought about the operating conditions and applicability of these ideal models for their experimental conditions. So far, there is no general agreement on the applicability of any given model for a specific detector under specific operating conditions, let alone a universal model for all detectors and all operating conditions. Further the related problem of pile-up is often confused with the deadtime phenomenon. Much work, is needed to devise a generalized and practical solution to these related problems. Many methods have been developed to measure and compensate for the detector deadtime count loss, and many researchers have addressed deadtime and pulse pile-up. The goal of this article is to summarize the state of science of deadtime; measurement and compensation techniques as proposed by some of the most significant work on these topics and to review the deadtime correction models applicable to present day radiation detection systems.

• Journal of Radiation Industry
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• v.5 no.1
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• pp.41-46
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• 2011

Polyacrylonitrile (PAN) fibers are the most widely used precursor of the materials for carbon fibers. The conventional process of carbon fibers from PAN precursor fiber includes two step; stabilization at low temperature and carbonization at high temperature. Compared to thermal stabilization, the stabilization process by electron beam (E-beam) irradiation is a advanced and brief method. However, a stabilization by E-beam irradiation was required a high dose (over 5,000 kGy) and spend over 1.5 hr (1.14 MeV, 1 mA). In the present work the main goal is exploring a quick stabilization process by cotrolling E-beam currents. The effect of various E-beam currents on stabilization of PAN precursor fiber was studied by gel fraction test, thermo gravimertic analysis (TGA), differential scanning calorimetry (DSC), tensile strength, and scanning electron microscopy (SEM) images.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.11
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• pp.367-373
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• 2017

The O2O service is an efficient way to operate based on systematic connection of the offline and online states. At present, education, health checkups, and exposure management of radiation workers are separated from offline and online at nuclear-related workplaces. Therefore, we developed a radiation workers management program at the workplace and tried to link online and offline states. After applying the program to the local network, we developed a written employee management system as a computer program and applied it to radiation workers and radiation safety managers at a university hospital in Daejeon using a questionnaire. As a result of the survey, the results of this program can enhance the awareness of safety management and work convenience. There is also a demand for radiation closed workers as well as radiation relative workers. It will be necessary to collect opinions regarding the characteristics of each workplace for the generalization of the radiation workers management program. As a result, real-time radiation safety management and work improvement can be expected through network connections between the workplace, supervisory authority, and related organizations in the future. If a circle structure is formed using the employee management program, development of radiation safety management can be expected.

• Proceedings of the IEEK Conference
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• 2002.07a
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• pp.425-428
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• 2002

The technology of Computer Graphics (CG) has been in great progress for almost 20 years and has proven to be a valuable tool for a broad variety of fields, including nuclear engineering. To work in any hazardous environment for example radiation field is particularly challenging because the danger is not always visually apparent. In this study as the application of CG to nuclear engineering field, we proposed to develop a radiation risk recognition aided system in which various radiation information; radiation risks, radiation distribution, hazard information and so on, were visualized by CG. The system used the server and client system. In the server there were two parts; one (main-server) was the database part having various data and the other (sub-server) was the visualization part visualizing the human phantom by POV-Ray. In the client there was the input and output part. The outputs from the system were various radiation information represented by coloring, circle graph and line graph intuitionally. The system is useful for a broad range of activities including radiation protection, radiation management, dose minimization, and demonstration to the public.

• 한국태양에너지학회:학술대회논문집
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• 2011.11a
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• pp.232-235
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• 2011

Radiation data are the best source of information for estimating average incident radiation. Lacking this or data from nearby locations of similar climate, it is possible to use empirical relationships to estimate radiation from days of cloudiness. It is necessary to estimate the regression coefficients in order to predict the daily global radiation on a horizontal surface. There fore many different equations have proposed to evaluate them for certain areas. In this work a new correlation has been made to predict the solar radiation for 16 different areas over Korea by estimating the regression coefficients taking into account cloud cover. Particularly, the straight line regression model proposed shows reliable results for estimating the global radiation on a horizontal surface with monthly average deviation of-0.26 to +0.53% and each station annual average deviation of -1.61 to +1.7% from measured values.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.20 no.10
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• pp.931-939
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• 2010

A dash panel plays an important role to protect noise as well as heat. Meanwhile, it is also the most important path that transfers energy to the interior cavity, so that some of noises are transferred via air and its structural vibration becomes a major issue. From the viewpoint of NVH performance, simplified structures analogues to the dash wall are dealt with. Stiffeners, damping sheets and sound packages attached to a flat panel are taken into account as design variables. Structural radiation characteristics(thus, structure borne) such as radiation efficiency and radiation power are mainly discussed. For the case when an excitation is applied on a frame that surrounds the panel, it is shown that the radiation efficiency increases by attaching a stiffener to the panel, which is similarly found from the case when a panel is directly excited. It seems more effective to attach damping sheets along the boundary area of the panel rather than its middle area. The radiation efficiency of sound packages may make a dominant contribution to transmission loss as well as sound radiation. Experimental work was carried out to verify the results based on the simulation study.