• Title/Summary/Keyword: Occupational dose

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A Comparison of Noise Level by Noise Measuring Methods (소음측정방법에 따른 평가소음도 비교)

  • Shim, Chur Goo;Roh, Jae hoon;Park, Jung Gyun
    • Journal of Korean Society of Occupational and Environmental Hygiene
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    • v.5 no.2
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    • pp.128-136
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    • 1995
  • The purpose of this study is to evaluate the difference of noise level according to noise measuring methods in the noisy working environments. Sound pressure level(SPL), equivalence sound level(Leq) and personal noise exposure dose(Dose) in the fifty-nine unit workplaces of the twenty-eight industries were measured and relating factors which were affected noise level were investigated. The results were as follows ; 1. The noise levels were $88.70{\pm}5.68dB(A)$ by SPL, $89.07{\pm}5.41dB(A)$ by Leq and $89.07{\pm}5.69$ by Dose. The differences of noise levels by three measuring methods were statistically significant(P<0.001) by repeated measure ANOV A. 2. Comparing with noise levels by general classes of noise exposure, noise levels of continuous noise were $89.14{\pm}5.19dB(A)$ by SPL, $89.45{\pm}4.65dB(A)$ by Leq and $90.04{\pm}5.09$ by Dose. Noise levels of intermittent noise were $87.90{\pm}6.52dB(A)$ by SPL, $88.40{\pm}6.63dB(A)$ by Leq and $90.10{\pm}6.80$ by Dose. The differences noise level of noise measuring methods by general classese of noise exposure were statistically not significant by repeated measure ANOV A. 3. Interaction between general classese of noise exposure and noise measuring methods for noise level was not statistically significant by repeated measure ANOVA. And the noise level by noise measuring methods were statistically significant by repeated measure ANOV A(P<.001) 4. Comparing with noise levels by unit workplace size, noise levels of large unit workplace were $90.73{\pm}5.87dB(A)$ by SPL, $91.32{\pm}5.50dB(A)$ by Leq and $91.82{\pm}6.06$ by Dose and noise levels of middle unit workplace were $88.31{\pm}5.26dB(A)$ by SPL, $88.41{\pm}4.83dB(A)$ by Leq and $89.69{\pm}5.05$ by Dose. And noise levels of small unit workplace were $94.89{\pm}4.10dB(A)$ by SPL, $85.35{\pm}4.11dB(A)$ by Leq and $86.87{\pm}4.98$ by Dose. The noise level differences of noise measuring methods by unit workplace size were statistically significant by repeated measure ANOV A(P<.05). 5. The noise level by noise measuring methods were statistically significant by repeated measure ANOV A(P<.001). But Interaction between workplace size and noise level measuring methods for noise level was not statistically significant by repeated measure ANOVA. According to the above results, there was a difference of the noise level among the three measuring methods. Therefore we must use the personal noise exposure dose using by noise dose meter, possible, to prvent occupational hearing loss in noisy working environment.

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Planning and decommissioning of a disused Theratron- 780 teletherapy machine and the dose assessment methodology for normal and radiological emergency conditions

  • Mohamed M.Elsayed Breky ;Muhammad S. Mansy;A.A. El-Sadek ;Yousif M. Mousa ;Yasser T. Mohamed
    • Nuclear Engineering and Technology
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    • v.55 no.1
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    • pp.238-247
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    • 2023
  • The present work represents a technical guideline for decommissioning a disused teletherapy machine model Theratron-780 and contains category one 60Co radioactive source. The first section predicts the dose rate from the source in case of normal and radiological emergency situations via FLUKA-MC simulation code. Moreover, the dose assessment for the occupational during the whole process is calculated and compared to the measured values. A suggested cordoned area for safety and security in a radiological emergency is simulated. The second section lists the whole process's technical procedures, including (preview, dismantle, securing, transport and storage) of the disused teletherapy machine. Results show that the maximum obtained accumulated dose for occupational were found to be 24.5 ± 4.9 μSv in the dismantle and securing process in addition to 3.5 ± 1.8 μSv during loading on the transport vehicle and unloading at the storage facility. It was found that the measured accumulated dose for workers is in good agreement with the estimated one by uncertainty not exceeding 5% in normal operating conditions.

Use of Rank Sum Method in Identifying High Occupational Dose Jobs for ALARA Implementation

  • Cho, Yeong-Ho;Kang, Chang-Sun
    • Nuclear Engineering and Technology
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    • v.30 no.5
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    • pp.444-451
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    • 1998
  • The cost-effective reduction of occupational radiation exposure (ORE) dose at a nuclear power plant could not be achieved without going through an extensive analysis of accumulated ORE dose data of existing plants. It is necessary to identify what are high ORE jobs for ALARA implementation. In this study, the Rank Sum Method (RSM) is used in identifying high ORE jobs. As a case study, the database of ORE-related maintenance and repair jobs for Kori Units 3 and 4 is used for assessment, and top twenty high ORE jobs are identified. The results are also verified and validated using the Friedman test, and RSM is found to be a very efficient way of analyzing the data.

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Radiation Dose Distribution of a Surgeon and Medical Staff during Orthopedic Balloon Kyphoplasty in Japan

  • Ono, Koji;Kumasawa, Takafumi;Shimatani, Keiichi;Kanou, Masatoshi;Yamaguchi, Ichiro;Kunugita, Naoki
    • Journal of Radiation Protection and Research
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    • v.47 no.2
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    • pp.86-92
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    • 2022
  • Background: The present study investigated the radiation dose distribution of balloon kyphoplasty (BKP) among surgeons and medical staff, and this is the first research to observe such exposure in Japan. Materials and Methods: The study subjects were an orthopedic surgeon (n = 1) and surgical staff (n = 9) who intervened in BKP surgery performed at the National Hospital Organization Disaster Medical Center (Tokyo, Japan) between March 2019 and October 2019. Only disposable protective gloves (0.022 mmPb equivalent thickness or less) and trunk protectors were used, and no protective glasses or thyroid drapes were used. Results and Discussion: The surgery time per vertebral body was 36.2 minutes, and the fluoroscopic time was 6.8 minutes. The average exposure dose per vertebral body was 1.46 mSv for the finger (70 ㎛ dose equivalent), 0.24 mSv for the lens of the eye (3 mm dose equivalent), 0.11 mSv for the neck (10 mm dose equivalent), and 0.03 mSv for the chest (10 mm dose equivalent) under the protective suit.The estimated cumulative radiation exposure dose of 23 cases of BKP was calculated to be 50.37 mSv for the fingers, 8.27 mSv for the lens, 3.91 mSv for the neck, and 1.15 mSv for the chest. Conclusion: It is important to know the exposure dose of orthopedic surgeons, implement measures for exposure reduction, and verify the safety of daily use of radiation during surgery and examination.

Study of correlation between airborne benzene and urinary trans,trans-muconic acid in Petrochemical industry processes (공기 중 벤젠과 소변 중 뮤콘산과의 상관성 연구)

  • Joo, Kui Don;Lee, Jong Seong;Choi, Seong Bong;Shin, Jae Hoon
    • Journal of Korean Society of Occupational and Environmental Hygiene
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    • v.16 no.4
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    • pp.356-363
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    • 2006
  • To investigate the exposure effect of benzene, we measured airborne benzene as external doses, uninary tt-muconic acid as an internal dose of benzene exposure and analyzed the relationship between tt-muconic acid concentration and benzene exposure. The study population of eight businesses included 157 workers(87 workers in field; exposure group, 70 workers in board; control group) who produce or use benzene in petrochemical industry. The concentrations of airborne benzene were evaluated by personal samples and urine was sampled at the pre and end shift. Urinary t,t-muconic acid as internal dose was to analyze the relationship with airborne benzene. The geometric means(GM) of airborne benzene was 0.0231 ppm(range ND-1.0471 ppm) in exposure group and 0.0147 ppm(range ND-0.3162 ppm) in control group. The geometric means(GM) of urinary t,t-muconic acid at end-shift was $196.8{\pm}2.23{\mu}g/g$ creatinine in exposure group and $149.2{\pm}2.08{\mu}g/g$ creatinine in control group. There was significant correlation between the airborne concentration of benzene and the urinary concentration of t,t-muconic acid( r=0.711, p<0.01). From the results of stepwise multiple regression analysis about t,t-muconic acid at end-shift, significant independents was airborne benzene. In this study, there were significant correlation between the urinary concentration of t,t-muconic acid and the airborne concentration of benzene. More extensive studies ruling out healthy worker effect is needed.

Optimal Monitoring Intervals and MDA Requirements for Routine Individual Monitoring of Occupational Intakes Based on the ICRP OIR

  • Ha, Wi-Ho;Kwon, Tae-Eun;Jin, Young Woo
    • Journal of Radiation Protection and Research
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    • v.45 no.2
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    • pp.88-94
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    • 2020
  • Background: The International Commission on Radiological Protection (ICRP) has recently published report series on the occupational intakes of radionuclides (OIR) for internal dosimetry of radiation workers. In this study, the optimized monitoring program including the monitoring interval and the minimum detectable activity (MDA) of major radionuclides was suggested to perform the routine individual monitoring of internal exposure based on the ICRP OIR. Materials and Methods: The derived recording levels and the critical monitoring quantities were reviewed from international standards or guidelines by the International Atomic Energy Agency (IAEA), the International Organization for Standardization (ISO), and the European Radiation Dosimetry Group (EURADOS). The OIR data viewer provided by ICRP was used to evaluate the monitoring intervals and the MDA, which are derived from the reference bioassay functions and the dose coefficients. Results and Discussion: The optimal monitoring intervals were determined taking account of two requirement conditions on the potential intake underestimation and the MDA values. The MDA requirement values of the selected radionuclides were calculated based on the committed effective dose from 0.1 mSv to 5 mSv. The optimized routine individual monitoring program was suggested including the optimal monitoring intervals and the MDA requirements. The optimal MDA values were evaluated based on the committed effective dose of 0.1 mSv. However, the MDA can be adjusted considering the practical operation of the routine individual monitoring program in the nuclear facilities. Conclusion: The monitoring intervals and the MDA as crucial factors for the routine monitoring were described to suggest the optimized routine individual monitoring program of the occupational intakes. Further study on the alpha/beta-emitting radionuclides as well as short lived gamma-emitting nuclides will be necessary in the future.

Evaluation of exposure to ionizing radiation of medical staff performing procedures with glucose labeled with radioactive fluorine - 18F-FDG

  • Michal Biegala;Marcin Brodecki;Teresa Jakubowska;Joanna Domienik-Andrzejewska
    • Nuclear Engineering and Technology
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    • v.56 no.1
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    • pp.335-339
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    • 2024
  • Employees of nuclear medicine facilities performing medical procedures with the use of open radioactive sources require continuous detailed control of exposure to ionizing radiation. Thermoluminescent (TL) detectors placed in dosimeters: for the whole body, for lenses, ring and wrist dosimeters were used to assess exposure. The highest whole-body exposure of (1.70 ± 1.09) µSv/GBq was recorded in nurses administering radiopharmaceutical to patients. The highest exposure to lenses and fingers was recorded for employees of the quality control zone and it was (8.08 ± 2.84) µSv/GBq and a maximum of (1261.46 ± 338.93) µSv/GBq, respectively. Workers in the production zone received the highest doses on their hands, i.e. (175.67 ± 13.25) µSv/GBq. The measurements performed showed that the analyzed workers may be classified as exposure category A. Wrist dosimeters are not recommended for use in isotope laboratories due to underestimation of ionizing radiation doses. Appropriately selected shields, which significantly reduce the dose received by employees, must be used in isotope laboratories. Periodic measurements confirmed that the appropriate optimization of exposure reduces the radiation doses received by employees.

Effect of Fiber Number Per Mass Concentration in Korean Produced Asbestos on Lung Function and Pathology (중량당 섬유수가 다른 국내산 석면이 폐 기능과 폐 조직에 미치는 영향 평가)

  • Chung, Yong Hyun;Han, Jeong Hee;Kang, Min Gu;Kim, Jong Kyu;Yang, Jeong Sun
    • Journal of Korean Society of Occupational and Environmental Hygiene
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    • v.22 no.4
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    • pp.301-308
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    • 2012
  • Objectives: To evaluate the pulmonary toxicity of 2 Korea asbestos(chrysotile, anthophyllite), Sprague-Dawely rats were exposed to 2 mg domestic asbestos by intratracheal instillation(IT). Methods: Lung function of rats was analyzed by pressure transducer(MAX1320, Buxco Electronics, USA). The effects of 2 mg asbestos(chrysotile ; $8,814,244{\times}10^{6}$ fibers/mg, average diameter 0.08 ${\mu}m$, average length 4.39 ${\mu}m$, anthophyllite ; $5,182{\times}10^{6}$ fibers/mg, average diameter 0.95 ${\mu}m$, average length 7.29 ${\mu}m$) on pulmonary function and pathological changes were evaluated at after a single IT. Lung function and histopathological evaluation were assessed in 5 animals from each group at each time point. Results: Due to differences in fiber numbers, chrysotile induce marked lung pathology and lung function change than anthophyllite at the same mass dose. Chrysotile showed notable thickening of interstitial areas surrounding the alveolar ducts and terminal bronchioles. Conclusions: On a mass dose basis, chrysotile that have 1,700 times numbers of fibers per unit weight than anthophyllite produced a greater persistent lung injury than anthophllite for at least 4 weeks after exposure.