• 대한디지털의료영상학회논문지
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• 제11권2호
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• pp.101-107
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• 2009

With the recent development of diagnosis using radiation and increasing demand of the medical treatment, we need to minimize radiation exposure dose. So, This is the method which reduce patient dose by measuring surface dose of radiographic change factor and by comparing theoretical and actual dose, when we take an X-ray which is generally used. By changing the factor of kV, mAs, FSD, whose range is 60 to 120 kV, 20 to 100 mAs, 80 to 180 cm, we compared theoretical surface dose with actual surface dose calculated by the simple calculation program, Bit system, and NDD-M method As a result, when kV and mAs were higher, theoretical surface dose and actual surface dose were more increased. but the higher FSD was, the more decreased surface dose was. According to this, the error were measured about 0.1 to 0.2 mGy in low dose part and about 0.7 to 1.5 mGy in high dose part. Therefore, this shows that theoretical surface dose calculation method is more correct in low dose part than in high dose part. In conclusion, we will have to make constant efforts which can reduce patient and radiographer's exposure dose, studying methods which can predict patient's radiation exposure dose more exactly.

• 한국방사선학회논문지
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• 제14권3호
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• pp.289-294
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• 2020

X-선영상의 품질과 환자의 피폭 관리를 위하여 X-선장치에서 출력되는 선량(공기 흡수선량(mGy)은 측정으로부터 자료화 하는 것이 필요하다. 이 연구의 목적은 X-선장치의 출력선량과 출력인자(Of)의 측정으로부터 출력선량을 계산할 수 있는 식을 구하는데 있다. X-선장치로부터 조사되는 X-빔의 출력선량과 출력인자는 XR멀티검출기를 사용하여 측정하였다. 결과로서, 관전류-조사시간 곱(mAs)으로 나누어진 측정된 출력선량과 설정관전압을 Allometric1 fit하여 출력선량 계산식을 얻었다. 이 식에 출력인자를 곱하여 최종 출력선량 계산식을 구하였다. 구하여진 최종 출력선량 계산식은 모든 관전압, 관전류, 조사시간, 조사야 그리고 거리에 적용하는데 유용할 것으로 사료된다.

• 대한방사선기술학회지:방사선기술과학
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• 제44권1호
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• pp.53-58
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• 2021

Kerma Area Product (KAP) is best indicator of radiation monitoring on radiographic examinations. KAP can be measured differently depending on the X-ray irradiation area, air kerma, souce-skin distance, type of equipment, etc. The major factors are exposure area and the air krema. The KAP currently used only considers the exposure area with X-rays and has a problem that KAP is always excessively overestimated from the dose received by an actual subject. Therefore, in this study, in order to measure the accurate KAP, a new area dose calculation that can be calculated by dividing the area where the actual X-ray is irradiated is presented, and the KAP is the real area. We compared and analyzed how much it was overestimated compared to the dose. The Skull AP projection and seven other projection were compared and analyzed, and the KAP was overestimated in each test by 52% to 60%. In this way, the effective KAP (EKAP) calculation developed through this study should be utilized to prevent extra calculation of the existing KAP, and only the accurate patient subject area should be calculated to derive the accurate area dose value. EKAP is helpful for control the patient's exposure dose more finely, and it is useful for the quality control of medical radiation exposure.

• 한국방사선학회논문지
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• 제17권3호
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• pp.367-373
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• 2023

비행시 승무원이나 승객은 우주방사선과 공기나 비행기 기체와 반응하여 발생한 2차 산란선 등에 의해 피폭을 받게 된다. 항공기 승무원의 경우 우주기상 환경 시뮬레이션을 이용하여 계산된 피폭선량으로 방사선 안전관리를 적용받고 있다. 하지만, 태양활동이나 고도, 비행경로 등에 따라 피폭선량이 가변적이어서 계산법보다는 항로별 측정하는 것이 권고되고 있다. 본 연구에서는 범용 Si 센서와 다중채널파고분석기를 이용하여 우주방사선 선량을 측정할 수 있는 선량계를 개발하였다. 선량계산은 미우주항공국의 우주방사선 측정장비인 CRaTER(Cosmic Ray Telescope for the Effects of Radiation)의 알고리즘을 적용하였다. 표준교정시설에서 Cs-137 662 keV 감마선으로 에너지 및 선량교정을 시행하였으며, 실험 범위에서 선량률 의존성이 없음을 확인하였다. 제작된 선량계를 이용하여 2023년 5월 두바이 인천 구간의 국제선에서 직접 선량을 측정한 결과 국내 우주방사선 선량평가코드(KREAM; Korean Radiation Exposure Assessment Model for Aviation Route Dose)로 계산된 결과와 12% 이내로 비슷하게 나타났으며, 고도와 위도가 높아짐에 따라 계산 결과와 동일하게 선량이 증가하는 것을 확인하였다. 좀 더 많은 실증적 검증 실험이 요구되는 제한점은 있지만, 항공기 내 또는 개인 피폭선량 모니터링에 가성비가 우수한 선량계로 충분한 활용 가능성을 확인하였다.

• 대한방사선기술학회지:방사선기술과학
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• 제46권6호
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• pp.509-517
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• 2023

This study analyzed imaging conditions and exposure index through clinical information collection and dose calculation programs in coronary angiography examinations. Through this, we aim to analyze the effective dose according to examination conditions and provide basic data for dose optimization. In this study, ALARA(As Low As Reasonably Achievable)-F(Fluoroscopy), a program for evaluating the radiation dose of patients and the collected clinical data, was used. First, analysis of imaging conditions and exposure index was performed based on the data of the dose report generated after coronary angiography. Second, after evaluating organ dose according to 9 imaging directions during coronary angiography, with the LAO fixed at 30°, dose evaluation was performed according to tube voltage, tube current, number of frames, focus-skin distance, and field size. Third, the effective dose for each organ was calculated according to the tissue weighting factors presented in ICRP(International Commission on Radiological Protection) recommendations. As a result, the average sum of air kerma during coronary angiography was evaluated as 234.0±112.1 mGy, the dose-area product was 25.9±13.0 Gy·cm², and the total fluoroscopy time was 2.5±2.0 min. Also, the organ dose tended to increase as the tube voltage, milliampere-second, number of frames, and irradiation range increased, whereas the organ dose decreased as the FSD increased. Therefore, medical radiation exposure to patients can be reduced by selecting the optimal tube voltage and field size during coronary angiography, maximizing the focal-skin distance, using the lowest tube current possible, and reducing the number of frames.

• 대한방사선기술학회지:방사선기술과학
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• 제39권3호
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• pp.305-312
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• 2016

본 연구에서는 진단용 X선 검사에서 환자에게 피폭되는 두부 및 사지를 다양한 선량 계산법을 통해 실측 선량과 비교 실험하였다. 또한 촬영 장비의 형태, 장비 설정조건, X선의 용량, X선관과 환자와의 거리, X선 후방산란차이 등을 고려한 새로운 계산 방법을 제시하여 피폭선량을 산출하였다. 그 결과 피부입사선량이 기존의 선량 계산법보다 실측과의 오차가 줄어들었으며, 환자가 피폭되는 선량을 쉽게 계산할 수 있었고 의료선량 평가가 이루어지게 되어 방사선 관련 종사자들의 의료 선량 관리가 더욱 수월해지는 계기가 될 것으로 사료된다.

• Journal of Radiation Protection and Research
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• 제49권1호
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• pp.1-18
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• 2024

Exponential growth has been observed in nuclear medicine procedures worldwide in the past decades. The considerable increase is attributed to the advance of positron emission tomography and single photon emission computed tomography, as well as the introduction of new radiopharmaceuticals. Although nuclear medicine procedures provide undisputable diagnostic and therapeutic benefits to patients, the substantial increase in radiation exposure to nuclear medicine patients raises concerns about potential adverse health effects and calls for the urgent need to monitor exposure levels. In the current article, model-based internal dosimetry methods were reviewed, focusing on Medical Internal Radiation Dose (MIRD) formalism, biokinetic data, human anatomy models (stylized, voxel, and hybrid computational human phantoms), and energy spectrum data of radionuclides. Key results from many articles on nuclear medicine dosimetry and comparisons of dosimetry quantities based on different types of human anatomy models were summarized. Key characteristics of seven model-based dose calculation tools were tabulated and discussed, including dose quantities, computational human phantoms used for dose calculations, decay data for radionuclides, biokinetic data, and user interface. Lastly, future research needs in nuclear medicine dosimetry were discussed. Model-based internal dosimetry methods were reviewed focusing on MIRD formalism, biokinetic data, human anatomy models, and energy spectrum data of radionuclides. Future research should focus on updating biokinetic data, revising energy transfer quantities for alimentary and gastrointestinal tracts, accounting for body size in nuclear medicine dosimetry, and recalculating dose coefficients based on the latest biokinetic and energy transfer data.

• 한국콘텐츠학회논문지
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• 제11권12호
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• pp.357-363
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• 2011

본 연구는 유리 선량계를 이용한 진단용 X선 장치 선량 및 선질의 입사표면선량 값과 선질 계수에 의한 계산 측정법을 바탕으로 비교 평가하여 의료 피폭 선량에 대해 연구하였다. 실제 측정에 의한 ESDs 값이 Mori에 의한 NDD-M 법에서 가장 큰 차이를 보였으며, Edmonds에 의한 계산법이 가장 적은 차이를 보였다. 또한 정류 방식에 따른 실 측정과 선량 계산법 차이는 삼상 정류 방식, 단상 정류 방식, 인버터 방식으로 차이가 적게 나타났다. 본 연구 결과는 향후 진단용 X-선 촬영 장치의 사용에 있어 환자의 피폭 선량을 예측하고 검사 조건을 조절하여 의료 피폭 선량을 절감할 수 있을 것이다.

• Journal of Radiation Protection and Research
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• 제43권4호
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• pp.143-153
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• 2018

Background: The determination of the amount of radionuclides and internal dose for the worker who may have intake of radionuclides results in a variation due to uncertainty of measurement data and ingestion information. As a result of this, it is possible that for the same internal exposure scenario assessors could make considerably different estimation of internal dose. In order to reduce this difference, internal exposure scenarios for nuclear facilities were developed, and intercomparison were made to determine the harmonization of dose assessment results among the assessors. Materials and Methods: Seven cases on internal exposures incidents that have occurred or may occur were prepared by referring to the intercomparison excercise scenario that NRC and IAEA have carried out. Based on this, 16 nuclear facilities concerned with internal exposure in Korea were asked to evaluate the scenarios. Each result was statistically determined according to the harmonization discrimination criteria developed by IDEAS/IAEA. Results and Discussion: The results were evaluated as having no outliers in all 7 cases. However, the distribution of the results was spread by various causes. They can be divided into two wide categories. The first one is the distribution of the results according to the assumption of the intake factors and the evaluation factors. The second one is distribution due to misapplication of calculation method and factors related to internal exposure. Conclusion: In order to satisfy the harmonization criteria and accuracy of the internal exposure dose evaluation, it is necessary that exact guidelines should be set on low dose, and various intercomparison cases also be needed including high dose exposure as well as the specialized education. The aim of the blind test is to make harmonization evaluation, but it will also contribute to securing the expertise and high quality of dose evaluation data through the discussion among the participants.

• 방사선산업학회지
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• 제18권3호
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• pp.223-226
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• 2024

It is essential to precisely evaluate the expected dose (collective dose) before performing high-exposure tasks in nuclear power plants because those have a high potential to cause significant radiation exposure to workers. A dose evaluation method is to design the scenarios of high-exposure tasks using computational codes, which allows for the calculation of the expected collective dose. Although these computational scenarios are useful for estimating the expected radiation dose and establishing radiation protection plans, the calculated doses may not perfectly match the actual doses that workers receive during tasks due to differences between the scenario and the actual circumstances in the radiation fields. Therefore, this study presents a methodology for calculating correction factors to improve the accuracy of dose predictions from computational scenarios. This approach aims to make the predicted collective dose before the task closer to the actual dose received by workers, thereby enhancing radiation safety for personnel performing high-exposure tasks. Additionally, these correction factors will help accurately predict doses under various working conditions in the future, contributing to minimizing radiation exposure risks for nuclear power plant workers.