• Title/Summary/Keyword: Radiation safety

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A Study on the Evaluation of Radiation Safety in Opened-Ceiling-Facilities for Radiography Testing (천장 개방형 RT 사용시설의 방사선 안전성 평가 연구)

  • Sung-Hoe, Heo;Won-Seok, Park;Seung-Uk, Heo;Byung-In, Min
    • Journal of the Korean Society of Radiology
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    • v.16 no.6
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    • pp.741-749
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    • 2022
  • Radiography-Testing that verify the quality of welding structures without destruction are overwhelmingly used in industries, but many safety precautions are required as radiation is used. The workers for Radiography-Testing perform the inspection by moving the Iridium-192 radiation source embedded in the transport container of the gamma-ray irradiator within or outside the facility. The general facility is completely blocked about radiation from the outside with thick concrete, but if it is difficult for worker to handle object of inspection, facilities ceiling can be opened. A general facility may be constructed using a theoretical dose evaluation method because all exterior facilities are blocked, but if the ceiling is open, it is not appropriate to evaluate radiation safety with a simple theoretical calculation method due to the skyshine effect. Therefore, in this study, the radiation safety of the facility was evaluated in the actual field through an ion chamber survey-meter and an accumulated dose-meter called as OSLD, and the actual evaluation environment was modeled and evaluated using the Monte Carlo simulation code as FLUKA. According to the direction of the irradiation, the radiation dose at the facility boundary was difficult to meet the standards set by the regulatory authority, and radiation safety could be secured through additional methods. In addition, it was confirmed that the simulation results using the Iridium-192 source were valid evaluation with the actual measured results.

The Clinical effectiveness and the radiation safety of newly developed Multileaf Collimator (새로 개발된 Multi-leaf Collimator의 임상 유효성 및 방사선 안전성에 관한 연구)

  • Yi, B.Y.;Kim, J.H.;Ahn, S.D.;Kim, M.H.;Chang, H.
    • Proceedings of the KOSOMBE Conference
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    • v.1996 no.05
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    • pp.157-160
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    • 1996
  • We have developed the prototype Multi-leaf Collimator(MLC) for medical linear acclerator. In this study, we have examined the clinical effectiveness of our newly developed MLC by analysing treatment pattern of radiation therapy and studied the radiation safety by measuring the transmitted radiation and the leakage radiation. Over 81% patients can be treated with new MLC(20 pairs of leaves) and 98% with 30 pairs of leafed-MLC, while 95% with commercial MLC. New MLC showed superior properties of radiation leakage and transmission to commercially available MLC.

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Analysis of Local Exposure Levels of Radiation Emitted from Soft X-ray Ionizers in LCD Manufacturing Processes (LCD 제조공정의 이온화 장치에 대한 전리방사선 지역노출특성 분석)

  • Kim, JoonBeom;Chung, Eun-Kyo;Jung, Kihyo
    • Journal of Korean Society of Occupational and Environmental Hygiene
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    • v.31 no.4
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    • pp.342-352
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    • 2021
  • Objectives: This study analyzed the local exposure levels of radiation emitted from the equipment with soft X-ray ionizers to investigate the radiation exposure levels in Liquid Crystal Display(LCD) manufacturing processes. Methods: This study measured the local radiation levels for the equipment installed in two LCD manufacturing companies. The equipment were installed at diverse processes and equipped with various number of ionizers. The local radiation levels were measured on the surface of the equipment by using direct reading equipment, and the measurements were converted into annual effective dose by considering the radiation exposure time of workers. Statistical analyses were performed to investigate the radiation exposure characteristics. Results: Annual effective doses for 97.6% of the equipment being measured were less than 1 mSv. However, the range of annual effective doses was 0.004 mSv ~ 2.167 mSv, which indicated a large variation among the equipment. Statistical analyses of the study found that this large variation was raised due to improper shielding of the equipment rather than process and/or equipment characteristics. To pinpoint the cause of this large variation in annual effective dose, this study improved the shielding of the equipment being radiated over 1 mSv and found that their average effective dose was reduced from 1.604 mSv to 0.126 mSv after shielding improvement. Conclusions: Relatively high exposure levels of radiation were observed in some equipment where their shielding were insufficiently thick and/or sealed. This finding implies that the shielding of the equipment is an important engineering countermeasure to control the radiation exposure levels in industries.

PRIMORDIAL RADIONUCLIDES DISTRIBUTION AND DOSE EVALUATION IN UDAGAMANDALAM REGION OF NILGIRIS IN INDIA

  • Manikandan, N.Muguntha;Selvasekarapandian, S.;Sivakumar, R.;Meenakshisundaram, V.;Raghunath, V.M.
    • Journal of Radiation Protection and Research
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    • v.26 no.3
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    • pp.183-190
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    • 2001
  • The activity concentration of primordial radionuclides i.e., $^{238}U$ series, $^{232}Th$ series and $^{40}K$, in soil samples collected from Udagamandalam environment, have been measured by employing NaI (Tl) Gamma ray Spectrometer. The absorbed gamma dose rate has also been simultaneously measured by using both Environmental Radiation Dosimeter at each soil sampling location (ambient gamma dose) as well as from the gamma dose derived from the activity concentration of the primordial radionuclides. The results of activity concentration of each radio nuclides in soil, absorbed dose rate in air due to soil activity and possible cosmic radiation at each location along with human effective dose equivalent for Udagamandalam environment are presented and discussed.

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RADIATION SAFETY STUDIES AT TOHOKU UNIVERSITY CYRIC

  • Yamadera M. Baba A.;Miura T.;Aoki T.;Hagiwara M.;Kawata N.
    • Journal of Radiation Protection and Research
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    • v.26 no.3
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    • pp.231-236
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    • 2001
  • A brief introduction is presented on the radiation safety studies at Tohoku University Cyclotron & Radioisotope Center. Studies on two subject are described; (1) measurement of the thick target neutron yield and radioisotope production / activation cross section for ten's of MeV neutrons and ions using K=110 Tohoku University cyclotron to provide basicdata for accelerator shielding, and (2) development of techniques for high sensitive radiation detection and profile measurement using an Imaging Plate which is a high sensitive two-dimensional radiation sensor. Application of the Imaging Plate techniques to localization of very weak radioactivity and to neutron profile measurement is described.

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Study on the Storage Stability of Xeno-Bone Graft Material by Irradiation (방사선 조사된 골수복제의 저장 안전성 평가)

  • Lee, Hak-Jyung;Kim, Jae-Hun;Kim, Tae-woon;Lee, Ju-Woon;Choi, Jong-il
    • Journal of Radiation Industry
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    • v.4 no.4
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    • pp.381-384
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    • 2010
  • In this study, the microbial safety and mechanical properties of xeno-bone graft material irradiated were investigated during the storage. Xeno-bone graft of the deminerlized bone matrix in carboxy-methyl-cellulose was gamma-irradiated and was cultured in PCA and PDA agar to check microbial contamination. Total aerobic bacteria and fungi were not detected in the irradiated and non-irradiated sample stored in accelerator at $30^{\circ}C$ for 10 months. Viscosity of CMC treated gamma irradiation was also not changed by holding period.

Development of an open-source GUI computer program for modelling irradiation of multi-segmented phantoms using grid-based system for PHITS

  • Hiroshi Watabe;Kwan Ngok Yu;Nursel Safakatti;Mehrdad Shahmohammadi Beni
    • 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.

Medical Physicists in the Field of Radiation Therapy for Unlicensed Activity (방사선치료분야에서 의학물리사 무면허행위 여부)

  • Jeong, Seong-Hyeun;Kim, Seung-Chul
    • The Journal of the Korea Contents Association
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    • v.13 no.12
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    • pp.869-879
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    • 2013
  • Modern medicine has not yet conquered behavior therapy for cancer radiation treatment, which is one of the professional groups involved in the justification of the act and reasonable human resources was analyzed. Radiation Oncology(Therapeutic Radiology) installed the role of the medical physicist in the current law, the act must have been within the limits given licenses, but the legitimacy of the act which can be given the current laws and regulations are not clear. Thus, certification and testing outside the medical physicist's research institutions, including the measures to be reflected in national legislation sought. Medical physicists, with the inherent illegality act because one of the areas to precluding the illegality of the content-based "medical law" and "Nuclear Safety Law", "medical technology in the field of radiation safety standards on management" was based on the interpretation. In conclusion, "medical law" and "in the field of medical technology on the management of radiation safety standards" that are consistent with the recognition of qualifications, increased activity in the radiation therapy and radiation safety management must deal with this will be feasible.