• The Korean Journal of Food & Health Convergence
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• v.4 no.1
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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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• v.41 no.3
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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.

• Journal of radiological science and technology
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• v.11 no.1
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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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• v.4 no.3
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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.

• Korean Journal of Digital Imaging in Medicine
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• v.12 no.1
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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.

• The Korean Journal of Zoology
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• v.18 no.1
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• pp.41-49
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• 1975

Dose response and time dependence of DNA repair synthesis were investigated to determine the possible relationship between DNA repair synthesis and chromosome exchanges in $\\gamma$-ray irradiated BHK-21 and KB cell lines. DNA repair synthesis induced by $\\gamma$-ray was dose dependent up to 5kR, then leveling off occurred until 50 kR was reached. Time dependence of DNA repair synthesis was continued for up to 1$\\sim$2 hours after irradiation although the initial dose responses were cell line specific. Chromosome exchanges induced by $\\gamma$-ray showed different radiosensitivities in these cell lines and did not show a correlation with the DNA repair synthesis.

• Radiation Oncology Journal
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• v.6 no.1
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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.

• Journal of radiological science and technology
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• v.39 no.3
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• pp.435-441
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• 2016

The importance of radiation dose display of medical X-ray equipment was emphasized, while third edition of IEC(International Electrotechnical Commission) 60601 started to apply. The existing medical X-ray equipment selected a method for attaching the DAP(Dose Area Product) meter when the dose display. However, because the DAP meter was dependent on all of the income, And it did not yet produced in Korea. So, we received the support of Seoul R&BD Program(Grants No. C1152055) to produce DAP meter prototype of the Domestically technology. In this study, the performance of this prototype was evaluated by comparing the German company's product Evaluation item was an electronic capture performance, radiation dose dependence, radiation quality dependence, energy transmittance, repeatability, light transmittance of 6 entries. And IEC 60580 was based on this evaluation. Evaluation results were electronic capture performance intrinsic error 9.5%, radiation dose dependence limits of variation 1%, repeatability coefficient of variation 2%, energy transmittance 91% each assessment was passed. However radiation quality dependence limits of variation 29%, light transmittance 55% was less than acceptance criteria.

• Journal of IKEEE
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• v.23 no.2
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• pp.739-742
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• 2019

In this paper, we propose enhanced DAP(Dose Area Product). The development of enhanced DAP proposed in this paper has optimized the area dose meter that was developed previously. The development of enhanced DAP performed Optimized design of charge integrator and ADC circuit, optimization of line transceiver for RS-485 communication, optimization of display circuit, and optimization of PC-based control program for interlocking and aging. As a result of evaluating the performance of the proposed system in an accredited testing laboratory, Radiation dose dependence and Radiation quality dependence were measured to be 4.2%, which is below ${\pm}15%$ of international standard. Energy range/Tube voltage was confirmed in the range of 30~150kV. The sensitivity difference between sensor field and sensor field area dose sensitivity was measured to be 4.3%, and it was confirmed that it operates normally under ${\pm}15%$ of international standard. In order to measure the reproducibility of the area dosimeter, it was confirmed that it was 0% and it was operated normally at less than 2% of IEC60580 recommendation. Digital resolution was confirmed to be a minimum unit of $0.01{\mu}Gy{\cdot}m^2$ within the error range for the reference dose per hour.

• Environmental Mutagens and Carcinogens
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• v.22 no.4
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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.