• 대한의용생체공학회:의공학회지
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• 제38권5호
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• pp.256-263
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• 2017

By using the buildup characteristics of the radiophotoluminescence glass dosimeter(RPLGD), it is aimed to help the measurement of the accurate dose by measuring the radiation dose according to the time of the glass element. Five glass elements were arranged on the table and the source to image receptor distance(SID) was set to 100 cm for the build-up radiation dose measurement of the fluorescent glass dosimeter glass element(GD-352M). Radiation doses and saturation rates were measured over time according to irradiation time, with the tube voltage (30, 60, 90 kVp) and tube current (50, 100 mAs) Repeatability test was repeated ten times to measure the coefficient of variation. The radiation dose increased from 0.182 mGy to 12.902 mGy and the saturation rate increased from 58.3% with increasing exposure condition and time. The coefficient of variation of the glass elements of the fluorescent glass dosimeter was ranged from 0.2 to 0.77 according to the X - ray exposure conditions. X - ray exposure showed that the radiation dose and saturation rate were increased with buildup characteristics, and degeneration of glass elements was not observed. The reproducibility of the variation coefficient of the radiation generator was included within the error range and the reproducibility of the radiation dose was excellent.

• Nuclear Engineering and Technology
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• 제42권1호
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• pp.89-96
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• 2010

This paper describes the methodology of calculating the internal dose conversion coefficient in order to assess the radiological impact on non-human species. This paper also presents the internal dose conversion coefficients of 25 radionuclides ($^3H,\;^7Be,\;^{14}C,\;^{40}K,\;^{51}Cr,\;^{54}Mn,\;^{59}Fe,\;^{58}Co,\;^{60}Co,\;^{65}Zn,\;^{90}Sr,\;^{95}Nb,\;^{99}Tc,\;^{106}Ru,\;^{129}I,\;^{131}I,\;^{136}Cs,\;^{137}Cs,\;^{140}Ba,\;^{140}La,\;^{144}Ce,\;^{238}U,\;^{239}Pu,\;^{240}Pu$) for domestic seven reference animals (roe deer, rat, frog, snake, Chinese minnow, bee, and earthworm) and one reference plant (pine tree). The uniform isotropic model was applied in order to calculate the internal dose conversion coefficients. The calculated internal dose conversion coefficient (${\mu}Gyd^{-1}$ per $Bqkg^{-1}$) ranged from $10^{-6}$ to $10^{-2}$ according to the type of radionuclides and organisms studied. It turns out that the internal does conversion coefficient was higher for alpha radionuclides, such as $^{238}U,\;^{239}Pu$, and $^{240}Pu$, and for large organisms, such as roe deer and pine tree. The internal dose conversion coefficients of $^{239}U,\;^{240}Pu,\;^{238}U,\;^{14}C,\;^3H$, and $^{99}Tc$ were independent of the organism.

• Journal of Radiation Protection and Research
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• 제21권4호
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• pp.297-311
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• 1996

ANSI는 교정용 팬텀으로 PMMA 평판형 팬텀을 제시하면서 이에 대한 선량당량환산 계수를 계산하는 방법을 제시하였다. PMMA 평판형 팬텀에 대한 광자의 선량당량환산계수는 ICRU조직 정육면체 팬텀에 대한 후방산란인자 및 선량당량환산계수와 PMMA 평판에 대한 후 방산란인자를 각각 구한 후 이를 이용하여 간접적으로 계산하도록 제시하였다. 그러나 중성자에 대한 PMMA 평판형 팬텀에서의 선량당량환산계수의 계산방법은 아직도 제시하지 못하고 있다. 이 연구에서는 ANSI가 제시한 광자에 대한 선량당량환산계수 계산방법을 중성자에 대해 적용하여 PMMA 평판에 대한 중성자의 선량당량환산계수를 최초로 계산하였다. 중성자에 대해 선질가중조직커마를 도입하여 ICRU 정육번체와 PMMA 평판에서 후방산간인자를 계산하였고 ICRU 정육면체에 대한 중성자의 선량당량환산계수를 계산한 후 이를 이용하여 PMMA 평판에서의 중성자에 대한 선량당량환산계수를 계산하였다. 그 결과 PMMA 평판에 대한 중성자의 선량당량환산계수는 대부분의 에너지 영역에서 ICRU 정육면체에 대한 중성자의 선량당량환산계수와 10% 이내의 차이를 보였으나 1eV. 1keV, 4 MeV에서는 $15{\sim}20%$, 정도 크게 나타났다.

• 한국방사선학회논문지
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• 제16권1호
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• pp.61-66
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• 2022

이 연구의 목적은 Ir¹⁹² 선원을 이용한 근접치료에서 물 흡수선량 1 Gy에 대한 광자 에너지플루언스와 질량에너지흡수계수를 유도하는데 있다. Khan이 저술한 방사선치료물리학으로부터 Ir¹⁹² 선원의 감마선 선속에 대한 납의 반가층을 얻었다. 얻어진 납의 반가층으로부터 선감쇠계수와 질량감쇠계수를 산출하였다. 산출된 납의 질량감쇠계수를 NIST의 납의 질량감쇠계수 자료에 대응시켜 일치하는 질량감쇠계수의 광자에너지를 유효에너지로 결정하였다. 결정된 유효에너지를 NIST의 물의 질량에너지흡수계수 자료의 광자에너지에 대응시켜서, 물의 질량에너지흡수계수는 0.03273 cm²/g(32.73 cm²/kg)으로 얻었다. 얻어진 물의 질량에너지흡수계수(32.73 cm²/kg)를 물 흡수선량 1 Gy에 나누어 광자에너지플루언스는 0.03055 J/cm²으로 산출하였다.

• Nuclear Engineering and Technology
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• 제55권11호
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• pp.4096-4101
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• 2023

Radon is a radioactive gas produced from the uranium-238 series. Radon gas affects public health and is the second cause of lung cancer. The study samples were collected from one area of the city of Jazan, southwest of the Kingdom of Saudi Arabia. The influence of engineering and physical parameters on the emanation coefficient of gas and other gas parameters was studied. Parameters for radon were measured using a CR-39 Solid-State Nuclear Track Detector (SSNTD) through a sealed emission container. The results showed that the emanation coefficient was affected directly by the change in the grain size of the soil. All parameters of measured radon gas have the same behavior as the emanation coefficient. The relationship between particle size and emanation coefficient showed a good correlation. The values of the emanation coefficient were inversely affected by the mass of the sample, and the rest of the parameters showed an inverse behavior. The results showed that increasing the volume of the container increases the accumulation of radon sons on the wall of the container, which increases the emission factor. The rest of the parameters of radon gas showed an inverse behavior with increasing container size. The results concluded that changing the engineering and physical parameters has a significant impact on both the emanation coefficient and all radon parameters. The emanation coefficient affects the values of the radiation dose of an alpha particle.

• Nuclear Engineering and Technology
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• 제53권4호
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• pp.1318-1322
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• 2021

To unveil and delineate the elements applicable to the radiation protection of a femoral entry shield, calculate its mass attenuation coefficient, and demonstrate its dose reduction efficacy for interventional radiologist performing transarterial embolization (TAE) of ruptured hepatocellular carcinoma (rHCC). The lead equivalency of the shield was firstly validated. Electron microscopy was used to confirm the femoral entry shield being lead-free and to analyze the elemental content, with which the mass attenuation coefficient of the shield was calculated. An adult phantom, irradiated at the upper abdomen to simulate the TAE of rHCC, was used together with a dosimeter attached to the palm of a hand phantom. The dose rates at the hand phantom were measured, with the rHCC clinical protocol, without and with the femoral entry shield placed over the right femoral access site of the adult phantom. Without using the shield, the average hand dose rate was measured to be 0.325 µSv/sec. While using the shield, it was determined to be 0.110 µSv/sec. There was significant 66% dose reduction to the hand dose of IRs performing angiographic intervention with the femoral entry shield.

• 대한방사선기술학회지:방사선기술과학
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• 제40권3호
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• pp.415-421
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• 2017

전립선암에서 방사선치료의 경우 직장의 선량을 감소시키기 위하여 항문을 통하여 일정한 양의 공기를 주입한 풍선을 이용한다. 이런 이유로 전립선암의 방사선치료는 매일 영상유도를 하기 위하여 CBCT를 획득하고 있다. 치료 전 처음 촬영한 전산화단층촬영과 가장 비슷한 상태의 해부학적 구조를 유지시키기 위하여 전처치를 하고 있지만 완벽하게 일치된다고 할 수 없다. 두 명의 실제 치료계획에서는 방광의 용적은 45.82 cc와 63.43 cc 및 등가직경 4.4 cm, 4.9 cm로 측정되었다. 본 연구의 20회 CBCT 결과에서 방광의 용적은 평균 56.2 cc, 105.6cc로 평가되었다. 치료계획 전산화단층촬영에서 평가된 선량과 A 환자의 기준으로 정한 CBCT의 선량은 PTV Mean dose는 1.74%, Bladder Mean dose는 96.67%의 차이로 평가되었으며, B 환자의 경우 PTV Mean dose는 4.31%, Bladder Mean dose는 97.35%의 차이로 평가되었다. 방광의 용적의 변화에 따라 PTV와 방광의 선량변화가 발생된다는 것을 알 수 있었다. 방광의 용적의 변화에 따른 방광 선량의 상관계수 값은 평균선량 $R^2=-0.94$의 선형성을 나타냈다. 방광의 용적변화에 따른 PTV선량의 상관계수 값은 평균선량 $R^2=0.04$의 선형성을 나타냈다. 방광 용적의 변화에 따라 PTV의 선량 변화가 방광의 선량변화보다 더 크다는 것을 알 수 있었다.

• 대한환경공학회지
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• 제27권10호
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• pp.1123-1128
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• 2005

흙냄새 혹은 곰팡이 냄새 등을 야기시키는 MIB는 남조류나 방선균등에 의해 생성되는 2차 대사산물이다. MIB는 일반적인 정수공정(응집, 침전, 여과)에 의해서는 쉽게 제거가 되지 않을 뿐만 아니라, 수돗물에 수 ng/L정도만 존재하더라도 소비자에게 심미적인 불쾌감을 유발시킬 수 있다. 일반적으로 MIB는 정확한 양의 PAC가 투입될 때 효과적으로 제거될 수 있으나, 대부분 정수장 운전자들은 PAC를 적당히 투입한 다음 처리 후 직접적인 관찰(냄새감지)에 근거하여 투입량을 조절함으로써 과잉투입 혹은 과소투입과 같은 결과를 야기하고 있는 실정이다. 이와 같은 배경을 바탕으로 본 연구에서는 $^{14}C$-radiolabled MIB을 이용한 등온흡착 및 흡착동역학 실험을 수행하여 HSDM에 필요한 물질전달계수와 표면확산계수를 결정하였다. HSDM은 실제 실험을 잘 모의하였으며, 실험 결과 또한 정확히 예측하였다. HSDM 결과에 근거하여 저자들은 Excel spreadsheet을 이용하여 최적 PAC 투입량 예측프로그램을 개발하였다. 개발된 프로그램을 실제 2개의 정수장에 적용한 결과 정수장 운전자의 경험에 의해 구해진 실제 PAC 투입량과 새롭게 개발된 프로그램에 의해 구해진 PAC 투입량 사이에 많은 차이를 보였다. 만약 정수장 운전자가 최적 PAC 투입량 예측프로그램을 이용하여 PAC 투입량을 결정한다면, 이 문제는 충분히 해결될 수 있을 것으로 판단된다.

• Nuclear Engineering and Technology
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• 제55권2호
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• pp.717-724
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• 2023

An essential step in evaluating and comparing the performance of two passive radiation dosimeter types, thermosluminescent (TLD) and optically stimulated luminescence (OSL), used by workers in environments with ionizing radiation for individual radiological monitoring and control of external exposure at various times (cumulative dose for 1 month), is to compare the measured dose accuracy, energy response, and coefficient of variation. In fact this performance study consists in determining the accuracy of both R(10) and R(0.07) which are considered as the ratios of the measured dose (Hp(10) or Hp(0.07)) to the delivered dose (Hp(10) or Hp(0.07)) for each photon energy. The validity of the results of this test is based on the acceptance limits of the ICRP and the international standard IEC-62387. The relative energy response used is normalized to the ¹³⁷Cs 662 keV energy to find which energy response is closest to the ideal case, and the coefficient of variation that allows to determine the statistical fluctuation of the Hp(10) and Hp(0.07) doses. The results of the accuracy test for the OSL and TLD dosimeters are acceptable because they fall within the ICRP limits. For the energy response, the OSL performs better than the TLD for Hp(10) and Hp(0.07), and for the coefficient of variation, the OSL satisfies the requirements of ISO 62387 for both Hp(10) and Hp(0.07), while the TLD satisfies these requirements only for the measurement of Hp (0.07).

• Nuclear Engineering and Technology
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• 제52권8호
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• pp.1798-1806
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• 2020

In this study, we investigated whether there is a significant relationship between the natural radiation dose rate and the cancer incidences in Korea by using a big data analysis. The natural dose rate data for this analysis were the measurement data obtained from the 171 monitoring posts of the 113 administrative districts in Korea over the 10 years from 2007 to 2016. The relative cancer incidences for this analysis were the difference in the cancer patients per hundred thousand people year-on-year in the administrative districts with the five highest and the five lowest natural gamma dose rates each year over the same period. To analyze the correlation between the two variables, Spearman's rank correlation coefficient between the two rates was derived using R, a well-known big data analysis tool. The analysis showed that Spearman's rank correlation coefficient was more than 0.05 and that the correlation between the two variables was not statistically significant.