• 대한방사선기술학회지:방사선기술과학
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• 제38권4호
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• pp.483-489
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• 2015

현대의 의료용 방사선 발생장치는 영상을 저장하고 전송하기 위해 의료영상 표준규격으로 Digital image communications in medicine(DICOM)을 채택하고 있다. DICOM 규격에서는 피폭선량 정보 표시를 위해 DICOM dose Structured Report(DICOM dose SR)를 표준으로 제정하여 사용하고 있다. 이와 더불어 DICOM Modality Performed Procedure Step(DIOCM MPPS) 정보와 DICOM tag 정보에서도 부분적인 피폭선량 정보를 표시하고 있다. 본 연구에서는 DICOM과 관련된 피폭선량정보 표시방법에 대해 고찰하고 의료정보 시스템간의 상호연동 테스트를 위한 Integrating the Healthcare Enterprise(IHE)의 Radiation Exposure Monitoring(REM) 프로파일에 대해 살펴보았다. 의료기관에서 의료방사선피폭선량정보에 대한 품질관리를 위해서는 DICOM 정보에서 표시되는 피폭선량 정보형식에 대한 이해가 반드시 수반되어야 하고 장비도입 단계에서 관련 규격에 대한 검토가 이루어져야 한다.

• 한국산업보건학회지
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• 제31권4호
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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.

• Journal of Radiation Protection and Research
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• 제34권2호
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• pp.55-64
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• 2009

In a pressurized heavy water reactor (PHWR), radiation workers who have access to radiation controlled areas submit their urine samples to health physicists periodically; internal radiation exposure is evaluated by the monitoring of these urine samples. Internal radiation exposure at PHWRs accounts for approximately 20 $\sim$ 40% of total radiation exposure; most internal radiation exposure is attributed to tritium. Carbon-14 is not a dominant nuclide in the radiation exposure of workers, but it is one potential nuclide to be necessarily monitored. Carbon-14 is a low energy beta emitter and passes relatively easily into the body of workers by inhalation because its dominant chemical form is radioactive carbon dioxide ($^{14}CO_2$). Most inhaled carbon-14 is rapidly exhaled from the worker's body, but a small amount of carbon-14 remains inside the body and is excreted by urine. In this study, a method for dual analysis of tritium and carbon-14 in urine samples of workers at nuclear power plants is developed and a method for internal dose assessment using its excretion rate result is established. As a result of the developed dual analysis of tritium and carbon-14 in urine samples of radiation workers who entered the high radiation field area at a PHWR, it was found that internal exposure to carbon-14 is unlikely to occur. In addition, through the urine counting results of radiation workers who participated in the open process of steam generators, it was found that the likelihood of internal exposure to either tritium or carbon-14 is extremely low at pressurized water reactors (PWRs).

• 방사선산업학회지
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• 제18권1호
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• pp.23-33
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• 2024

This study was conducted to analyze the characteristics of three high-exposure tasks performed by radiation workers in Korean pressurized water reactors (PWRs) and to identify factors that reduce their exposure during work. Three high-exposure tasks were selected based on a previous study. In this previous study, nozzle dam installation and removal, eddy current testing, and manway opening and closing were determined as high-exposure tasks through normalization (radiation dose per unit time). Based on the analysis of the characteristics of the high-exposure tasks in this study, the high-exposure tasks were steam generator-related tasks performed inside and outside the water chamber. This study analyzed the reduction factors for high-exposure tasks and suggested improvements in terms of time, distance, and shielding. The use of the characteristics of high-exposure tasks and their dose reduction factors enables Korean PWRs to optimize radiation protection for workers who receive relatively high doses.

• 방사성폐기물학회지
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• 제19권2호
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• pp.243-253
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• 2021

In the dismantling process of a reactor coolant system (RCS) piping, a radiation protection plan should be established to minimize the radiation exposure doses of dismantling workers. Hence, it is necessary to estimate the individual effective dose in the RCS piping dismantling process when decommissioning a nuclear power plant. In this study, the radiation exposure doses of the dismantling workers at different positions was estimated using the MicroShield dose assessment program based on the NUREG/CR-1595 report. The individual effective dose, which is the sum of the effective dose to each tissue considering the working time, was used to estimate the radiation exposure dose. The estimations of the simulation results for all RCS piping dismantling tasks satisfied the dose limits prescribed by the ICRP-60 report. In dismantling the RCS piping of the Kori-1 or Wolsong-1 units in South Korea, the estimation and reduction method for the radiation exposure dose, and the simulated results of this study can be used to implement the radiation safety for optimal dismantling by providing information on the radiation exposure doses of the dismantling workers.

• 치과방사선
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• 제22권1호
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• pp.87-94
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• 1992

The purpose of this study was to evaluate the effect of scatter radiation to dental x-ray film with long time-exposure in the different structures of the tooth, by using pinhole camera. For this study, pinhole camera, skull with tooth, and pocket dosimeter were used. The radiation with 70 and 90kVp and exposure time (minimum: 2.5 min., maximum 10 hrs.) was projected to the film in the pinhole camera. And density of the obtained x-ray film was measured with densitometer. In the intra-oral film taking, the amount of exposure of the scatter radiation affecting the thyroid gland area was measured with the dosimeter at the thyroid gland. The density of radiographs was compared in radiation projected with or without the metal cone of dental machine. The effect of the back scatter radiation to the film was also evaluated when the lead foil was removed. The obtained results were as follows: 1. A pinhole camera was a valuable device for locating the source of x-ray. 2. The scatter radiation affected the dental x-ray film when the radiation source was exposed. more than 5 hours'. In that case, the density of the scatter radiation could be observed visually. 3. The scatter radiation caused by short exposure of dental radiation didn't affect the diagnostic quality of the dental x-ray film. 4. The differences of densities between the tooth and the soft tissue according to exposure time showed 0.16 in 5 hours' exposure & 0.17 in 10 hours' exposure at 70 kVp & 0.12 in 5 hours' exposure & 0.13 in 10 hours' exposure at the 90kVp. 5. The differences of densities between the tooth and the soft tissue according to kVp showed no difference between 5 hours' exposure of tooth at 70 kVp and soft tissue at 90 kVp, but showed 0.05 high density in tooth when 10 hours' exposure at 90 kVp. 6. No difference of density was on radiographs taken with or without dental machine cone. 7. Back scatter radiation was recorded image of radiographs for only 3 min. 8. The amounts of the scatter radiation exposed to the thyroid gland in intraoral film taking were 1.12 mr in upper anterior, 0.55 mr in upper posterior, 2.75 mr in lower anterior, and 1.92 mr in lower posterior teeth.

• Journal of Radiation Protection and Research
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• 제19권1호
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• pp.37-50
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• 1994

X-선과 감마선의 에너지에 따른 선질특성과 선량 및 필름의 사진농도와의 관계를 이용한 필름배지선량계의 선량환산식을 실험적으로 체계화 하였고, 시간경과에 따른 잠상퇴행 특성과 방사선의 입사방향에 따른 방향특성을 실험적으로 조사하여 보정계수를 산출하였다. 본 연구에서 구한 선량환산식은 필름배지선량계의 기술기준인 성능판정 기준을 잘 만족시키는 것으로 나타났다.

• 방사선산업학회지
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• 제18권2호
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• pp.141-145
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• 2024

In Publication No. 66 of the International Commission on Radiological Protection, an activity median aerodynamic diameter (AMAD) of 5 ㎛ is considered in internal exposure dose assessment owing to inhalation of radionuclides in a workplace. However, analysis of aerosols generated during dismantling experiments, such as in the oxy-cutting of a reactor vessel conducted in Korea, revealed that the radioactive aerosols have AMAD ranging from 0.024 to 0.064 ㎛. Such extremely fine aerosols can induce internal exposure if inhaled. In particular, alpha radionuclides in aerosols can lead to significantly higher levels of radiation exposure than beta and gamma radionuclides, thus highlighting the need to establish appropriate internal exposure radiation protection programs and monitoring systems that specifically address alpha radionuclides when decommissioning nuclear power plants in Korea.

• 방사선산업학회지
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• 제18권2호
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• pp.117-126
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• 2024

This study aims to identify high exposure tasks among the tasks performed in domestic nuclear power plants as a basis for developing training programs to improve the efficiency of workers' work. To this end, we first analyzed the exposure status of radiation work in domestic nuclear power plants. Radiation tasks in nuclear power plants were categorized, collective doses were investigated, and the collective doses were calculated based on the collective doses, and representative high exposure tasks were identified. We found that the collective and individual doses in domestic nuclear power plants are continuously decreasing, but there is an imbalance of exposure among workers. In terms of work classification, nuclear power plants are managed in 236 work codes based on light water reactors and 181 work codes based on heavy water reactors, depending on the work equipment and location. Among the total work codes, 23 codes have an annual average dose exceeding 10 μSv, and based on this, 10 representative high exposure tasks were derived. The representative high exposure tasks were selected as S/G nozzle dam work, S/G debris removal work, nuclear instrumentation system, S/G eddy current detection work, and insulation work. The results of this study are expected to serve as an important basis for reducing the exposure of workers in nuclear power plants and improving work efficiency.

• 한국산업보건학회지
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• 제27권3호
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• pp.170-179
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• 2017

Objectives: This study aims to investigate the occupational radiation exposures of emergency medical technicians(EMTs) in emergency medical centers in Korea. The results will provide a basis for developing prevention programs to minimize adverse health effects relating to radiation exposure among emergency medical technicians working in this area. Methods: Radiation exposure doses were measured for twenty-two EMTs working in six emergency medical centers. Thermo Luminescent Dosimeters(TLD) were placed on three representative body parts, including chest, neck, and a finger. Measurements were conducted over the entire working hours of the participants for foor weeks. Dosimeters were analyzed according to a standard method by a KFDA-designated lab. Detection rate, annual radiation exposure dose, and relative levels to dose limit were derived based on the measured doses from the dosimeters. SPSS/Win 18.0 software(IBM, US) was used for statistical analysis. Results: Detection rates were 45.5%, 36.4%, and 45.5% for the dosimeters sampled from chest, neck, and a finger, respectively. The average annual doses were $2.39{\pm}3.44mSv/year$(range 0.38-10.0 mSv/year) for the chest, $2.72{\pm}3.05mSv/year$(2.00-11.34) for the neck, and $20.98{\pm}17.57mSv/year$(1.25-53.50) for the hand dose. The average annual eye dose was estimated to $3.61{\pm}2.37mSv/year$(1.50-8.34). The exposure dose levels of EMTs were comparable to those of radiologists, who showed relatively higher radiation dose among health care workers, as reported in another study. Conclusions: EMTs working in emergency medical centers are considered to be at risk of radiation exposure. Although the radiation exposure dose of EMTs does not exceed the dose limit, it is not negligible comparing to other professionals in health care sectors.