• Journal of Institute of Control, Robotics and Systems
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• v.9 no.4
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• pp.296-303
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• 2003

A personal portable type electronic dosimeter using silicon PIN photodiode and small GM tube is recently attracting much attention due to its advantages such as an immediate indication function of dose and dose rate, alerting function, and efficient management of radiation exposure history and dose data. We designed and manufactured a semiconductor radiation detector aimed to directly measure X-ray and v-ray irradiated in silicon PIN photodiode, without using high-priced scintillation materials. Using this semiconductor radiation detector, we developed an active electronic dosimeter, which measures the exposure dose using pulse counting method. In this case, it has a shortcoming of over-evaluating the dose that shows the difference between the dose measured with electronic dosimeter and the dose exposed to the human body in a low energy area. We proposed an energy compensation filter and developed a dose conversion algorithm to make both doses indicated on the detector and exposed to the human body proportional to each other, thus enabling a high-precision dose measurement. In order to prove its reliability in conducting personal dose measurement, crucial for protecting against radiation, the implemented electronic dosimeter was evaluated to successfully meet the IEC's criteria, as the KAERI (Korea Atomic Energy Research Institute) conducted test on dose indication accuracy, and linearity, energy and angular dependences.

• Korean Journal of Clinical Pharmacy
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• v.27 no.3
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• pp.127-135
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• 2017

Background: Kawasaki disease (KD) is an acute febrile, systemic vasculitis as a leading cause of acquired heart disease in children. Intravenous immunoglobulin G (IVIG) and aspirin are the standard initial therapy in the treatment of acute KD. The purpose of this study was to investigate drug utilization in children with KD, and to compare "IVIG + high-dose aspirin" and "IVIG + moderate-dose aspirin" in preventing cardiac complications. Methods: We analyzed pediatric patient sample data compiled by the Health Insurance Review & Assessment Service from 2010 to 2015. We identified patients with KD using the KCD-6 code of M30.3. We excluded patients in chronic phase or ${\geq}1$0 years. We also excluded patients who were diagnosed KD in November or December. Drug utilization pattern were assessed in acute KD patients and 30-day and 60-day cardiac complications were investigated between "IVIG + high-dose aspirin" group and "IVIG + moderate-dose aspirin" group. Results: In acute phase, IVIG was administered to 95.8% patients, and 57.1% patients were prescribed moderate-dose aspirin and 25% patients were with high-dose aspirin. Steroid use was rapidly increased from 4.0% in 2010 to 11.3% in 2015. Both 30-day and 60-day cardiac complications occurred less in "IVIG + high-dose aspirin" group compared to "IVIG + moderate-dose aspirin" group, but not statistically significant (0.9% vs 1.8%, p=0.252 for 30-day complication rate; 1.5% vs 2.7%. p=0.073 for 60-day complication rate). Conclusion: We were not able to demonstrate which aspirin therapy is superior for preventing cardiac complications in acute KD patients and further research is warranted.

• Journal of Radiation Protection and Research
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• v.5 no.1
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• pp.1-6
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• 1980

A portable count-ratemeter and a thermoluminescent detector ($CaSO_4:Dy$) have been used to obtain total gamma dose rates at approximately 50 locations during the course of several survey trips in the southeastern Korea. The purposes of these measurement were to provide a future reference data and to establish the approximate range of population exposure to the natural environmental radiation. The natural levels encountered ranged from a low of 14.6 microroentgen per hour to a high of 18.9 microroentgen per hour with a mean of $16.3{\pm}1.0$ microroentgen per hour. Among these results are the relatively high natural dose rate levels in the Masan area and Yangsan-Tongdosa area with the relatively low natural dose rate levels in the Gyeongsan-Cheongdo area and the Samrangjin-Jinyeong-Gimhae area.

• Nuclear Engineering and Technology
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• v.55 no.9
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• pp.3417-3422
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• 2023

Recently, as the clinically positive biological effects of ultra-high dose rate (UHDR) radiation beams have been revealed, interest in flash radiation therapy has increased. Generally, FLASH preclinical experiments are performed using UHDR electron beams generated by linear accelerators. Real-time monitoring of UHDR beams is required to deliver the correct dose to a sample. However, it is difficult to use typical transmission-type ionization chambers for primary beam monitoring because there is no suitable electrometer capable of reading high pulsed currents, and collection efficiency is drastically reduced in pulsed radiation beams with ultra-high doses. In this study, a monitoring method using bremsstrahlung photons generated by irradiation devices and a water phantom was proposed. Charges collected in an ionization chamber located at the back of a water phantom were analyzed using the bremsstrahlung tail on electron depth dose curves obtained using radiochromic films. The dose conversion factor for converting a monitored charge into a delivered dose was determined analytically for the Advanced Markus® chamber and compared with experimentally determined values. It is anticipated that the method proposed in this study can be useful for monitoring sample doses in UHDR electron beam irradiation.

• Journal of radiological science and technology
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• v.33 no.3
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• pp.269-276
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• 2010

This study attempts to propose ways to optimize and improve the period of hospitalization for the radioiodine treatment by calculating the dose rate of patients treated with high-dose radioiodine by distance and time slot. As a result, 24 hours after the patient was treated with 100 mCi high-dose iodine, the dose rate was attenuated to $1,035{\mu}Sv/hr$ at the navel, to $109{\mu}Sv/hr$ at 50 cm, and to $33{\mu}Sv/hr$ at 100 cm. 24 hours after the patient was treated with 150 mCi high-dose iodine, the dose rate was attenuated to $637{\mu}Sv/hr$ at the navel, to $100{\mu}Sv/hr$ at 50 cm, and to $40{\mu}Sv/hr$ at 100 cm. 24 hours after the patient was treated with 180 mCi high-dose iodine, the dose rate was attenuated to $1,251{\mu}Sv/hr$ at the navel, $140{\mu}Sv/hr$ at 50 cm, and to $56{\mu}Sv/hr$ at 100 cm. In light of the current criterion for discharge recommended by the US Nuclear Regulatory Commission being $70.4{\mu}Sv/hr$, the present study indicates earlier discharge is feasible by applying a new scheme. This suggests that the proposed scheme in this study will help to solve the problem of shortage of treatment beds with the increasing trend of patients with thyroid cancer taken into consideration.

• 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.

• Progress in Medical Physics
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• v.14 no.1
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• pp.15-19
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• 2003

High dose rate (HDR) brachytherapy for treating a cervix carcinoma has become popular, because it eliminates many of the problems associated with conventional brachytherapy. In order to improve the clinical effectiveness with HDR brachytherapy, a dose calculation algorithm, optimization procedures, and image registrations need to be verified by comparing the dose distributions from a planning computer and those from a phantom. In this study, the phantom was fabricated in order to verify the absolute doses and the relative dose distributions. The measured doses from the phantom were then compared with the treatment planning system for the dose verification. The phantom needs to be designed such that the dose distributions can be quantitatively evaluated by utilizing the dosimeters with a high spatial resolution. Therefore, the small size of the thermoluminescent dosimeter (TLD) chips with a dimension of <1/8"and film dosimetry with a spatial resolution of <1mm used to measure the radiation dosages in the phantom. The phantom called a pelvic phantom was made from water and the tissue-equivalent acrylic plates. In order to firmly hold the HDR applicators in the water phantom, the applicators were inserted into the grooves of the applicator holder. The dose distributions around the applicators, such as Point A and B, were measured by placing a series of TLD chips (TLD-to-TLD distance: 5mm) in the three TLD holders, and placing three verification films in the orthogonal planes. This study used a Nucletron Plato treatment planning system and a Microselectron Ir-192 source unit. The results showed good agreement between the treatment plan and measurement. The comparisons of the absolute dose showed agreement within $\pm$4.0 % of the dose at point A and B, and the bladder and rectum point. In addition, the relative dose distributions by film dosimetry and those calculated by the planning computer show good agreement. This pelvic phantom could be a useful to verify the dose calculation algorithm and the accuracy of the image localization algorithm in the high dose rate (HDR) planning computer. The dose verification with film dosimetry and TLD as quality assurance (QA) tools are currently being undertaken in the Catholic University, Seoul, Korea.

• Korean Journal of Environmental Biology
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• v.19 no.3
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• pp.205-210
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• 2001

To determine the effect of low dose gamma radiation on the germination and enzyme activities, seeds of Chinese cabbage (Brassica compestris L. cv. Hanyoreum) and radish (Raphanus sativus L. cv. Chungsukoungzoung) were irradiated at the dose of 2-50 Gy. The germination rate of irradiation group was higher than that of the control. Especially it was highest at the early stage. The germination rate of Chinese cabbage was high at 2 Gy and 8 Gy irradiation group and that of radish was high at 2 Gy, 6 Gy and 10 Gy irradiation group. Growth of both seedlings of Chinese cabbage and radish increased positively in low dose irradiation group. The height of Chinese cabbage was noticeably high at 4 Gy and 10 Gy irradiation group and that of radish at 6 Gy irradiation group. The protein contents of seedlings from seeds irradiated with the low dose gamma radiation was higher than the control, especially at the early stage. The enzyme activities of seedlings from seeds irradiated with the low dose gamma radiation was high at 4 Gy and 10 Gy irradiation group. These results suggest that the germination, growth and enzyme activities of old vegetable seeds could be promoted by the low dose gamma radiation.

• Progress in Medical Physics
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• v.6 no.1
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• pp.49-57
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• 1995

The semiconductor detector has a high sensitive to radiation and a small volume. It has been frequently used in high energy photon and electron beamdosimetry. However, Semiconductor detector are subject to radiation damage in high energy radiation beam which reduces the sensitivity and creat a large discrepancy. In this experiments, P-type semiconductor was irradiated to 18 MeV electron beam with pre-irradiation for reducing the sensitivity for high reproducibility and investigated the dose characteristics against the dose rate variations. The sensitivity per unit dose in small dose rate showed a 35％ large different to a large dose rate with pre-irradiation dose for 0.5 KGy and 20％ for 3 KGyin this study. The silicon detector has showed a large dependency of beam direction with 13％ discrepancy and a linear sensitive as increased temperature.

• Toxicological Research
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• v.15 no.1
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• pp.9-17
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• 1999

This study was performed to evaluate the subacute toxicity of CJ-50002 (Vibrio Vaccine) in SPF Spraqur-Dawley (SD) rats. Vibrio vaccine was administered orally at a dose level of high (167mg/kg/day), medium (16.7mg/kg/day), and low (16.7mg/kg/day) once a day and repeated fro 4 weeks. Ten males and female rats were assigned to each group. After 4 week administration, no significant dose-dependent changes in body weight, water and food consumption rate or organ weight were noted dependent changes in body weight, water and food consumption rate or organ weight were noted among 4 groups. Urinanalysis, hematology, and serum chemistry, also fail to detect any dose-related change among 4 groups tested. During necropsy and histopathological examination, no specific toxicity related to treated material was found. The result of this study demonstrated that vibrio vaccine when administered orally for 4 weeks at a high dose of 167mg/kg/day, no dose-related toxicity was found in treated make and female rats.