• 대한방사선기술학회지:방사선기술과학
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• 제46권3호
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• pp.219-229
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• 2023

In this study, basic characteristics such as reproducibility, linearity, and directionality of RPL glass dosimeters were evaluated to improve the reliability of dose evaluation through RPL glass dosimeters, and uncertainty elements such as sensitivity by glass element and magazine slot sensitivity were evaluated. Using a mathematical model to calibrate the measured values of the RPL glass dosimeter, the measurement uncertainty was calculated assuming an example. As a result of the characteristic evaluation, the RPL glass dosimeter showed excellent performance with a standard deviation of ±1% (1 SD) for the reproducibility of the reading process, a coefficient of determination for linearity of 0.99997. And the read-out of the RPL glass dosimeter are affected by the circular rotation direction of the glass dosimeter during irradiation, fading according to the period after irradiation, the number of laser pulses of the reader, and response degradation due to repeated reading, it is judged that measurement uncertainty can be reduced by irradiation and reading in consideration of these factors. In addition, it was confirmed that the dose should be determined by calculating the correction factors for the sensitivity of each element and, the sensitivity of each reading magazine slot. It is believed that the reliability of dosimetry using glass dosimeters can be improved by using a mathematical model for correction of glass dosimeter readings and calculating measurement uncertainty.

• Journal of the Korean Physical Society
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• 제73권9호
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• pp.1377-1384
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• 2018

Accurate measurement of the absorbed dose and the effective dose is required in dental panoramic radiography involving relatively low energy with a rotational X-ray tube system using long exposures. To determine the effectiveness of measuring the irradiation by using passive dosimetry, we compared the entrance skin doses by using a radiophotoluminescent glass dosimeter (RPL) and an optically stimulated luminescence detector (OSL) in a phantom model consisting of nine and 31 transverse sections. The parameters of the panoramic device were set to 80 kV, 4 mA, and 12 s in the standard program mode. The X-ray spectrum was applied in the same manner as the panoramic dose by using the SpekCalc Software. The results indicated a mass attenuation coefficient of $0.008226cm^2/g$, and an effective energy of 34 keV. The equivalent dose between the RPL and the OSL was calculated based on a product of the absorbed doses. The density of the aluminum attenuators was $2.699g/cm^3$. During the panoramic examination, tissue absorption doses with regard to the RPL were a surface dose of $75.33{\mu}Gy$ and a depth dose of $71.77{\mu}Gy$, those with regard to the OSL were surface dose of $9.2{\mu}Gy$ a depth dose of $70.39{\mu}Gy$ and a mean dose of $74.79{\mu}Gy$. The effective dose based on the International Commission on Radiological Protection Publication 103 tissue weighting factor for the RPL were $0.742{\mu}Sv$, $8.9{\mu}Sv$, $2.96{\mu}Sv$ and those for the OSL were $0.754{\mu}Sv$, $9.05{\mu}Sv$, and $3.018{\mu}Sv$ in the parotid and sublingual glands, orbit, and thyroid gland, respectively. The RPL was more effective than the OSL for measuring the absorbed radiation dose in low-energy systems with a rotational X-ray tube.

• Journal of Radiation Protection and Research
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• 제46권3호
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• pp.106-111
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• 2021

Background: Crookes tube is utilized in junior high and high schools in Japan to study the character of electrons and current, and not for radiological education. There is no official guideline or regulation for these radiation source to the public. Therefore, most teachers have no information about the leakage of X-rays from Crookes tube. The peak energy of X-rays is approximately 20 keV, and it is impossible to measure using conventional survey meters. Materials and Methods: Each leakage dose of low energy X-rays from 38 Crookes tube in the education field, such as junior and senior high schools in Japan, was explored by the teachers in the school using radio-photoluminescence (RPL) dosimeters. Before and after the measurements, the dosimeters were sent by postal mails. Results and Discussion: At the exploration in this study, it was estimated that the 70 ㎛ dose equivalent, H_p(0.07) of X-rays from 31 Crookes tubes were smaller than 100 µSv in 10 minutes, at the distance of 1 m, where the Crookes tube was usually observed. However, the highest dose was estimated as 0.69 mSv by an equipment with the full power. Furthermore, one Crookes tube exhibited 0.62 mSv with minimum output power of the induction coil. This relatively large dose was reduced by the shorter distance of discharge electrodes of the induction coil. Conclusion: The leakage dose of low energy X-rays from 38 Crookes tube was explored using RPL dosimeters. It was estimated that the H_p(0.07) of X-rays from 31 Crookes tubes were smaller than 100 µSv in 10 minutes at the distance of 1 m, while some equipment radiated a higher dose. With this study, the provisional guideline for the safety operation of Crookes tube is established.

• 한국콘텐츠학회논문지
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• 제10권5호
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• pp.343-350
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• 2010

체외충격파쇄석술(Extracorporeal shock wave lithotripsy ; ESWL) 시 환자가 받는 방사선 피폭선량을 측정하기 위하여 신장 및 요관 결석으로 진단을 받은 총 55명(남:36명, 여:19명)을 대상으로 방사선피폭선량을 측정하였다. 측정 방법은 투시 관전압 80kVp, 관전류 5mA로 고정하여 인체 모형의 Rando Phantom과 형광유리 선량계를 사용하였으며, 주요 장기인 양측 신장, 방광, 간에 5분과 10분씩 각각 2회 흡수선량을 측정하여 유효선량으로 환산하였다. 환자 당 평균 시행 횟수는 1.8회(1~4)이었고, 평균 투시시간은 533초(248~2516)로 나타났다. 우측 신장결석 치료 시 우측 신장의 평균값은 2.458mSv, 좌측 신장은 0.152mSv, 간은 1.404mSv, 방광은 0.019mSv로 측정 되었고, 좌측 신장결석 치료 시 좌측 신장의 평균값은 2.496mSv, 우측 신장은 0.252mSv, 간은 0.178mSv, 방광은 0.017mSv이었으며, 하부요관 결석치료 시 방광에서의 평균값은 3.742mSv, 우측 신장은 0.009mSv, 좌측 신장은 0.01mSv로 유효선량이 측정 되었다.