• 식품보건융합연구
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• 제4권1호
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• pp.15-22
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• 2018

A radiation dosimeter is important to assess quality assurance (QA) of radiation therapy devices and to estimate the radiation dose in vivo dosimetry. Recently, optically stimulated luminescence detector (OSLD) is widely used in clinical filed. Therefore, the purpose of this study is to evaluate dose, energy, and angular dependence of OSLD and EBT3 film. The absorbed dose in clinical linear accelerator (Linac) beam is calibrated for dose per monitor unit (MU). Dose, energy, and angular dependence of OSLD and EBT3 film are estimated after the calibration procedure. The absorbed dose is measured at 50, 100, 150, and 200 cGy in an 6 MV X-ray beam for dose dependence. A dose of 150 cGy is delivered to OSLD and EBT3 film with 6 and 10 MV photon energies for energy dependence. For measurements of angular dependence, angular positions of gantry are $0^{\circ}{\pm}80^{\circ}$ with 6 MV at 150 cGy. The results of dose dependence is linear for OSLD and EBT3 film. For the results of energy dependence, errors were 0.39% and 0.03% for OSLD and EBT3 film, respectively. The results of dose for angular is decreased from $0^{\circ}$ to ${\pm}80^{\circ}$ for both OSLD and EBT3 film. When angle of $0^{\circ}$ is normalized to 1, and the dose is decreased to 60 and 66% at $80^{\circ}$ for OSLD and EBT3 film, respectively. Dose and energy dependence of OSLD and EBT3 film are measured within the recommendation of manufacturer. Angular dependence is increased from $0^{\circ}$ to ${\pm}80^{\circ}$ for OSLD and EBT3 film. The characteristics of OSLD and EBT3 film are similar and expected to useful for clinical field.

• Journal of Radiation Protection and Research
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• 제41권3호
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• pp.229-236
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• 2016

Background: In order to manage the patient exposure dose in X-ray diagnosis, it is preferred to evaluate the entrance skin dose; although there are some evaluations about entrance skin dose, a small number of report has been published for direct measurement of patient. We think that a small-type optically stimulated luminescence (OSL) dosimeter, named nanoDot, can achieve a direct measurement. For evaluations, the corrections of angular and energy dependences play an important role. In this study, we aimed to evaluate the angular and the energy dependences of nanoDot. Materials and Methods: We used commercially available X-ray diagnostic equipment. For angular dependence measurement, a relative response of every 15 degrees of nanoDot was measured in 40-140 kV X-ray. And for energy dependence measurement, mono-energetic characteristic X-rays were generated using several materials by irradiating the diagnostic X-rays, and the nanoDot was irradiated by the characteristic X-rays. We evaluated the measured response in an energy range of 8.1-75.5 keV. In addition, we performed Monte-Carlo simulation to compare experimental results. Results and Discussion: The experimental results were in good agreement with those of Monte-Carlo simulation. The angular dependence of nanoDot was almost steady with the response of 0 degrees except for 90 and 270 degrees. Furthermore, we found that difference of the response of nanoDot, where the nanoDot was irradiated from the randomly set directions, was estimated to be at most 5%. On the other hand, the response of nanoDot varies with the energy of incident X-rays; slightly increased to 20 keV and gradually decreased to 80 keV. These results are valuable to perform the precise evaluation of entrance skin dose with nanoDot in X-ray diagnosis. Conclusion: The influence of angular dependence and energy dependence in X-ray diagnosis is not so large, and the nanoDot OSL dosimeter is considered to be suitable dosimeter for direct measurement of entrance surface dose of patient.

• 대한방사선기술학회지:방사선기술과학
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• 제11권1호
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• pp.33-41
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• 1988

This study was measured the radiation-induced current - X-ray dose, dose rate, X-ray quality, time, temperature, electric field characteristics and the dependence of gap length in insulating oil under of D.C. Voltage before, during and after X-ray irradiation. The obtained results can be summarized as following. 1. The radiation - induced current is more the dependence of X-ray quality (tube voltage) than quantity (tube current), the dependence of quantity is appeared at the high than low X-.ay tube voltage. 2. The dependence of dose rate is appeared at the more dose rate, and ${\triangle}\;=\;0.64{\sim}0.74$. 3. The higher temperature of insulating oil and X-ray tube voltage (X-ray quality) is increased, at the low electric field, the more radiation-induced current. 4. $G_{eq}-G_{o}(={\triangle}G)$ is increased at the low than high temperature, high than low X-ray quality. 5. The dependence of temperature is appeared before than during X-ray irradiation. 6. The RIC saturation region is appeared at the high than low insulating oil temperature during (1000 V/cm above) than before (4000 V/cm above) X-ray irradiation.

• Biomolecules & Therapeutics
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• 제4권3호
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• pp.232-238
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• 1996

The physical dependence potency of DA-5018, a non-narcotic analgesic agent, was tested in mice dosed with 0.5 and 4 mg/kg/day for 2 months and daily increasing doses of 1, 2, 4, 6, 8 and 10 mg/kg over 10 days. Physical dependence was assessed taking natural withdrawal induced morphine-type abstinence (jumping, falling, biting or backward locomotion, rearing etc.) as well as barbiturates-type abstinence (body weight reduction, convulsion, ataxia etc.) into consideration. The results were compared with those after the same daily increasing doses of morphine. DA-5018 did not show evidence of physical dependence liability or abuse potential as measured by morphine-type or barbiturate-type abstinence signs following daily increasing or 2-month repeated administration. On the other hand, daily increasing doses of morphine produced physical dependence and the dependent state disappeared about 6 hours after the start of withdrawal signs. In the single dose suppression test, a single dose of morphine completely suppressed natural withdrawal signs that appeared in morphine-dependent animals. Therefore, these results indicate that DA-5018 does not have abuse potential and physical dependence liability.

• 대한디지털의료영상학회논문지
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• 제12권1호
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• pp.65-69
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• 2010

High energy electron beams were to concentrically dose inside a tumor and more energy is a shape decreased of dose. Therefore, it is useful to radiation therapy of a tumor. Also high energy electron beams ionized into collision with a atom in structure material of tissue and it has big changes to dose distribution by multiple scattering. The study had to establish characteristic of electron beams from interaction of electron beams and materials. Experiment method was to measure dependence of electron beam central axis for depth dose curve, field flatness and symmetry and field size dependence. The results were able to evaluate data for a datum pint of electron beam. Also radiotherapy has to be considered for not only energy pencil of lines but characteristic, electron guide and isodose curves distribution.

• 한국동물학회지
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• 제18권1호
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• pp.41-49
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• 1975

DNA 回復合成과 染色體交換과의 聯關性을 추구하기 위해 감마線을 照射한 BHK-21 과KB 細胞의 DNA 回復合成의 線量反應과 時期를 調査하였다. 감마 線에 의한 DNA 回復合成率은 5kR까지 照射線量에 比例하나 그후 50kR 까지는 變化가 없었다. DNA 回復合成의 初期 線量反應은 細胞에 따라 다르나 照射후 1$\\sim$2時間까지 지속하였다. 감마 線에 의한 染色體交換은 細胞에 따라 다른 感受性을 보였고 DNA 回復合成과의 聯關性을 보여주지 않았다.

• Radiation Oncology Journal
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• 제6권1호
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• pp.109-116
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• 1988

The Alcyon Co-60 gamma rays was studied for electron contamination. The surface dose, attributable almost entirely to contamination electrons, has a linear dependence on field width for square fields and an inverse square dependence on distance from the bottom of the fixed head assembly Build-up and surface dose measurements were taken with and without an acrylic blocking tray in place. Further measurements were made with a copper filter designed to reduce secondary electrons emitted by photon interactions with the acrylic tray. The results are discussed in relation to skin sparing effect for radiation therapy Patients. And to achieve the maximum skin sparing effect, the selection of the optimum SSD and TSD is needed.

• 대한방사선기술학회지:방사선기술과학
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• 제39권3호
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• pp.435-441
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• 2016

현재 시중에 설치되어 있는 의료용 X선 장치는 선량표시를 할 때 일반적으로 DAP(Dose Area Product) meter를 부착한다. 그러나 DAP meter가 전부 수입에 의존하고 있기 때문에 고가의 설치 비용 등의 문제가 있다. 본 연구에서는 서울시의 지원을 받아 순수 국산기술의 DAP meter 프로토타입을 제작하였고, 이 프로토타입의 성능을 독일산 I사의 제품과 비교하여 평가하였다. 평가 항목은 전자포집효율, 선량의존성, 선질의존성, 재현성, 자체흡수율, 광투과율 6개 항목으로 IEC 60580를 평가 기준으로 삼았다. 평가 결과 전자포집효율이 고유오차 9.5%, 선량의존성이 선형성 99%, 재현성이 변동계수 2%, 자체흡수율이 9%로 각각 합격기준을 만족시켰으나, 선질의존성이 변동한계 29%, 광투과율이 55%로 합격기준에 미달하였다. 아직 프로토타입이기에 앞으로 개선될 여지가 많다. 회로부터 재료까지 국산기술로 개발하고 있기 때문에 합격 기준에 미달하는 항목은 추후 해결 가능할 것으로 사료된다.

• 전기전자학회논문지
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• 제23권2호
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• pp.739-742
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• 2019

본 논문에서는 성능이 향상된 면적선량계(DAP)를 제안한다. 본 논문에서 제안한 성능이 향상된 면적선량계는 기존에 개발되었던 면적선량계를 최적화하였다. 성능이 향상된 면적선량계는 전하 적분기 및 ADC 회로의 최적화 설계, RS-485 통신용 Line transceiver의 최적화 설계, Display 회로의 최적화 설계, 연동 및 에이징을 위한 PC 기반 제어 프로그램 최적화 등을 수행하였다. 제안된 시스템의 성능을 평가하기 위하여 공인시험기관에서 실험한 결과는 Radiation dose dependence와 Radiation quality dependence는 4.2%의 측정 불확도가 측정되어 국제 표준인 ${\pm}15%$ 이하에서 정상동작 됨이 확인되었다. Energy range/Tube voltage는 30~150kV 구간에서 반응이 확인되었다. 센서필드간 감도차이와 센서필드간 면적선량 감도차이는 4.3%의 측정 불확도가 측정되어 국제 표준인 ${\pm}15%$ 이하에서 정상동작 됨이 확인되었다. 면적선량계의 재현성을 측정하기 위하여 10회 반복하여 측정한 결과 0%로 확인되어서 IEC60580 권고 사항인 2% 이하에서 정상동작 됨이 확인되었다. Digital resolution은 시간당 기준선량에 대해 오차 범위 내에서 $0.01{\mu}Gy{\cdot}m^2$의 최소단위로 측정되는 것을 확인되었다.

• 한국환경성돌연변이발암원학회지
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• 제22권4호
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• pp.266-273
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• 2002

The dose dependence of the severity of radiation-induced thymic lymphoma in C57BL/6J mice was studied. Mice were exposed to fractionated irradiation at the total doses of 4.0, 6.0 and 8.0 Gy (four irradiations at 8-day intervals) starting from 33 days after birth. Pathological and histological changes of each mouse were observed after periodical sacrifice at day 75, 100, 125, 150, 175, 200, 250, 300 after the first irradiation. The severity of cancers were classified into 4 stages by clinical signs with respect to the enlargement of the thymus, spleen, liver, the progression of the cancer in the thymus, and the metastasis to the spleen, liver, lung and the lymphatic nodes. Among the 490 mice observed, 146 mice had thymic lymphoma. A clear dose-effect relationship was observed as well as the dose-response relationship. Also, periodical observation showed that thymic lymphoma was first induced in mice sacrificed at day 100 (130days old), and metastasize in the order of spleen, lung, liver and then the lymphatic nodes. The results suggest that radiation may be involved not only as a tumor initiator but also as a tumor promoter, and a tumor progression-enhancing agent.