• Journal of Radiation Protection and Research
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• 제38권1호
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• pp.44-51
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• 2013

상대적으로 높은 항공승무원의 우주방사선 피폭을 고려하여 ICRP는 직무피폭의 일부로 간주하고 방사선 방호 대상으로 권고하였으며 이미 유럽 등 일부 국가에서는 항공 고도에서의 항공승무원에 대한 우주방사선 피폭 관리가 이루어지고 있다. 국내에서도 2012년 7월 26일 생활주변방사선안전관리법의 시행과 더불어 항공승무원에 대한 관리 기준이 마련되었다. 본 연구에서는 항공승무원의 개인 선량 평가에서 휴대가 용이한 누적형 고체비적검출기의 적용가능성을 검토하기 위해 수행되었다. 한국표준과학연구원에서 $^{252}Cf$ 중성자 표준 선원을 이용해 선량계의 중성자 선량에 대한 반응도의 선형성과 중성자 입사각에 따른 각도의존성을 평가하였고 한국민간항공조종사협회의 협조를 얻어 항공 고도에 선량계를 노출시켰다. 응답 특성 평가 결과, 선형성에서는 각각의 감속재에 대해 모두 상관계수($r^2$)가 0.99 이상으로 높았고 큰 각도의존성을 나타내었다. 또한 예측된 운항 승무원의 중성자 선량과 비적 밀도와의 상관성은 각각의 감속재에 대하여 r=0.486 (HDPE), r=0.241 (PA)으로 낮게 평가되었다. 누적형 중성자 선량계는 개인 피폭 선량 평가에 활용 가능성이 있을 것으로 판단되나 항공 고도에서의 중성자 에너지 스펙트럼을 고려하여 추가적인 연구가 필요하며 노출 시간을 증가시켜 비적 밀도와의 상관성을 보다 면밀하게 평가할 필요가 있다.

• Journal of Radiation Protection and Research
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• 제39권4호
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• pp.213-217
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• 2014

중재방사선을 이용한 의료적 시술이나 진단은 꾸준히 증가하고 있다. 특히 환자에 근접하여 이루어지는 중재방사선시술의 특성상 시술자에 대한 직무피폭의 관리 및 감시가 중요하다. 개인선량계를 통해 측정되는 방사선 방호 실용량인 심부선량은 중재방사선시술의 경우 균질한 방사선장에 의해 전신에 고르게 노출되는 경우가 아니므로 유효선량을 항상 대표할 수는 없다. 따라서 본 연구에서는 C-arm을 이용한 대표적인 중재방사선시술에 대해 수학적 모의피폭체와 몬테카를로 방법을 이용한 계산과 개인선량계를 이용한 실측을 통해 개인선량당량과 장기별 선량을 평가하고자 하였다. 주요 장기별 선량평가 결과는 개인선량계로 측정된 선량 값보다 낮았으나, 갑상선과 같은 장기는 전신 연조직 선량보다 상당히 높은 것으로 평가되었다. 중재방사선시술자에 대한 적절한 방사선방호를 위해 납치마의 착용과 같은 전신 방호와 더불어 갑상선 방호와 같은 추가적인 방호조치가 고려되어야 할 것이다.

• 디지털융복합연구
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• 제10권11호
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• pp.449-457
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• 2012

본 연구의 목적은 PET/CT 검사시 공간선량을 측정 비교함으로써 방사선 발생원과 종사자간 선량의 상관관계를 규명하고 효율적인 관리를 통해 피폭선량을 감소시키는데 있다. 최근 PET/CT 검사의 증가는 동위원소 사용량의 증가와 더불어 종사자의 피폭 증가의 원인이 되고 있다. 따라서 각 방사선 발생원에서의 공간선량을 비교 분석하고 개인방호복과 차폐체 사용에 관한 연구를 수행하였다. 양전자 방출핵종인 $^{18}F$ 방출 감마선 고에너지(511 keV)에서 개인방호복(0.5 mm pb) 사용은 미사용 시 보다 더 많은 피폭을 초래함을 확인하였다.

• Journal of Korean Neurosurgical Society
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• 제64권6호
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• pp.933-943
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• 2021

Objective : Percutaneous pedicle screw (PPS) fixation is a needle based procedure that requires fluoroscopic image guidance. Consequently, radiation exposure is inevitable for patients, surgeons, and operation room staff. We hypothesize that reducing the production of radiation emission will result in reduced radiation exposure for everyone in the operation room. Research was performed to evaluate reduction of radiation exposure by modifying imaging manner and mode of radiation source. Methods : A total of 170 patients (680 screws) who underwent fusion surgery with PPS fixation from September 2019 to March 2020 were analyzed in this study. Personal dosimeters (Polimaster Ltd.) were worn at the collar outside a lead apron to measure radiation exposure. Patients were assigned to four groups based on imaging manner of fluoroscopy and radiation modification (pulse mode with reduced dose) : continuous use without radiation modification (group 1, n=34), intermittent use without radiation modification (group 2, n=54), continuous use with radiation modification (group 3, n=26), and intermittent use with radiation modification (group 4, n=56). Post hoc Tukey Honest significant difference test was used for individual comparisons of radiation exposure/screw and fluoroscopic time/screw. Results : The average radiation exposure/screw was 71.45±45.75 µSv/screw for group 1, 18.77±11.51 µSv/screw for group 2, 19.58±7.00 µSv/screw for group 3, and 4.26±2.89 µSv/screw for group 4. By changing imaging manner from continuous multiple shot to intermittent single shot, 73.7% radiation reduction was achieved in the no radiation modification groups (groups 1, 2), and 78.2% radiation reduction was achieved in the radiation modification groups (groups 3, 4). Radiation source modification from continuous mode with standard dose to pulse mode with reduced dose resulted in 72.6% radiation reduction in continuous imaging groups (groups 1, 3) and 77.3% radiation reduction in intermittent imaging groups (groups 2, 4). The average radiation exposure/screw was reduced 94.1% by changing imaging manner and modifying radiation source from continuous imaging with standard fluoroscopy setting (group 1) to intermittent imaging with modified fluoroscopy setting (group 4). A total of 680 screws were reviewed postoperatively, and 99.3% (675) were evaluated as pedicle breach grade 0 (<2 mm). Conclusion : The average radiation exposure/screw for a spinal surgeon can be reduced 94.1% by changing imaging manner and modifying radiation source from real-time imaging with standard dose to intermittent imaging with modified dose. These modifications can be instantly applied to any procedure using fluoroscopic guidance and may reduce the overall radiation exposure of spine surgeons.

• 방사성폐기물학회지
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• 제21권3호
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• pp.371-381
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• 2023

Evaluating the effectiveness of the radiation protection measures deployed at the Centralized Radioactive Waste Management Facility in Ghana is pivotal to guaranteeing the safety of personnel, public and the environment, thus the need for this study. Radiagem^TM 2000 was used in measuring the dose rate of the facility whilst the personal radiation exposure of the personnel from 2011 to 2022 was measured from the thermoluminescent dosimeter badges using Harshaw 6600 Plus Automated TLD Reader. The decay store containing scrap metals from dismantled disused sealed radioactive sources (DSRS), and low-level wastes measured the highest dose rate of 1.06 ± 0.92 µSv·h^-1. The range of the mean annual average personnel dose equivalent is 0.41-2.07 mSv. The annual effective doses are below the ICRP limit of 20 mSv. From the multivariate principal component analysis biplot, all the personal dose equivalent formed a cluster, and the cluster is mostly influenced by the radiological data from the outer wall surface of the facility where no DSRS are stored. The personal dose equivalents are not primarily due to the radiation exposures of staff during operations with DSRS at the facility but can be attributed to environmental radiation, thus the current radiation protection measures at the Facility can be deemed as effective.

• 대한방사선기술학회지:방사선기술과학
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• 제44권6호
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• pp.629-633
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• 2021

This article is designed to look into the radiation exposure dose to each body part and the shielding effect for workers using an additional shielding to reduce their radiation exposured by scattering radiation which is generated in a space between the operating table and lead curtain during interventional radiology(IR) procedures. After placing a human phantom on the table of SIEMENS' angiography machine, the following measurements were taken, depending on the presence of an additional shield of lead equivalent of 0.25 mmPb, manufactured for this purpose: dose to gonad, dose to an area where the personal dosimeter is placed, and dose to an area of eye lens is located. An ion chamber(chamber volume 1,800 cc) was utilized to measure scattering radiation. The two imaging tests were carried out as follows: fluoroscopy of the abdomen (66 kV, 100 mA, 60 seconds) and of the head (70 kV, 65 mA, 60 seconds); and digital subtraction angiography(DSA) of the abdomen (67 kV, 264 mA, 20 seconds) and of the head (79 kV, 300 mA, 20 seconds). In all the experiments, the shielding efficiency of the gonad position was the largest at 59.8%. In case an additional shielding was used as protection against scattering radiation that came through the operating table and the lead curtain during an IR, the radiation shielding efficiency was estimated to be up to 59.8%, leading to a conclusion that its presence may effectively reduce the radiation exposure dose of medical staffs.

• International Journal of Computer Science & Network Security
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• 제22권2호
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• pp.15-22
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• 2022

Modern technology drives the world, increasing performance while reducing labor and time expenses. Tanzania Atomic Energy Commission (TAEC) tracks employee's levels of exposure to radiation sources using dosimeters. According to legal compliance, workers wear dosimeters for three months and one month at the workplace. However, TAEC has problems in tracking, issuing and returning dosimeters because the existing tracking is done manually. The study intended to develop a Personal Dose Management System (PDMS) that processes and manages the data collected by dosimeters for easy and accurate records. During the requirements elicitation process, the study looked at the existing system. PDMS' requirement gathering included document reviews, user interviews, and focused group discussions. Development and testing of the system were implemented by applying the evolutionary prototyping technique. The system provides a login interface for system administrators, radiation officers, and Occupational Exposed Workers. The PDMS grants TAEC Staff access to monitor individual exposed workers, prints individual and institutional reports and manages workers' information. The system reminds the users when to return dosimeters to TAEC, generate reports, and facilitates dispatching and receiving dosimeters effectively. PDMS increases efficiency and effectiveness while minimizing workload, paperwork, and inaccurate records. Therefore, based on the results obtained from the system, it is recommended to use the system to improve dosimeter data management at the institution.

• 한국의료질향상학회지
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• 제20권1호
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• pp.60-73
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• 2014

Objectives: This study aims at decreasing spatial dose rate through work improvement whilst spatial dose rate is the cause of increasing personal exposure dose which occurs in the process of handling radioisotope. Methods: From February 2013 until July 2013, divided into "before" and "after" the improvement, spatial dose rate in laboratory of nuclear medicine was measured in gamma image room, PET/CT-1 image room, and PET/CT-2 image room as its locations. The measurement time was 08:00, 12:00 and 17:00, and SPSS 21.0 USA was opted for its statistical analysis. Result: The spatial dose rate at distribution worktable, injection table, the entrance to the distribution room, and radioisotope storage box, which had showed high spatial dose rate, decreased by more than 43.7% a monthly average. The distribution worktable, that had showed the highest spatial dose rate in PET/CT-1 image room, dropped the rate to 42.3% as of July. The injection table and distribution worktable in the PET/CT-2 image room also showed the decline of spatial dose rate to 89% and 64.4%, respectively. Conclusion: By improving distribution process and introducing proper radiation shielding material, we were able to drop the spatial dose rate substantially at distribution worktable, injection table, and nuclide storage box. However, taking into account of steadily increasing amount of radioisotope used, strengthening radiation related regulations, and safe utilization of radioisotope, the process of system improvement needs to be maintained through continuous monitoring.

• 한국환경보건학회지
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• 제48권3호
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• pp.131-137
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• 2022

Public interest has been increasing the focus on the management of exposure to pollutants and the related health effects. This study reviewed exposure assessment methodologies and addressed future directions. Exposure can be assessed by direct (exposure monitoring) or indirect approaches (exposure modelling). Exposure modelling is a cost-effective tool to assess exposure among individuals, but direct personal monitoring provides more accurate exposure data. There are several population exposure models: stochastic human exposure and dose simulation (SHEDS), air pollutants exposure (APEX), and air pollution exposure distributions within adult urban population in Europe (EXPOLIS). A South Korean population exposure model is needed since the resolution of ambient concentrations and time-activity patterns are country specific. Population exposure models could be useful to find the association between exposure to pollutants and adverse health effects in epidemiologic studies. With the advancement of sensor technology and the internet of things (IoT), exposure assessment could be applied in a real-time surveillance system. In the future, environmental health services will be useful to protect and promote human health from exposure to pollutants.

• 한국의학물리학회:학술대회논문집
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• 한국의학물리학회 2002년도 Proceedings
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• pp.237-240
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• 2002

Knowing the dose distribution in a tissue is as important as being able to measure exposure or absorbed dose in radiotherapy. Since the Dry Imager spread, the wet type automatic processor is no longer used. Furthermore, the waste fluid after film development process brings about a serious problem for prevention of pollution. Therefore, we have developed a measurement method for the dose distribution (CR dosimetry) in the phantom based on the imaging plate (IP) of the computed radiography (CR). The IP was applied for the dose measurement as a dosimeter instead of the film used for film dosimetry. The data from the irradiated IP were processed by a personal computer with 10 bits and were depicted as absorbed dose distributions in the phantom. The image of the dose distribution was obtained from the CR system using the DICOM form. The CR dosimetry is an application of CR system currently employed in medical examinations to dosimetry in radiotherapy. A dose distribution can be easily shown by the Dose Distribution Depiction System we developed this time. Moreover, the measurement method is simpler and a result is obtained more quickly compared with film dosimetry.