• Journal of Radiation Protection and Research
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• v.21 no.3
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• pp.147-153
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• 1996

The Korea Atomic Energy Research Institute(KAERI) conducted a intercomparison study for personnel dosimetry services in Korea to enhance the accuracy and precision of the dosimetry system. Nine types of dosimeters(6 TLD, 3 film badge) from 7 institutions took part in this intercomparison study. Each participant submitted 30 dosimeters including transit control for irradiations. Both TLDs and film badges were irradiated with Cs-137 gamma, Sr/Y-90 beta and 4 X-ray beams in ISO wide series. Four dosimeters were irradiated on phantom with same dose equivalent for each field category. The delivered dose equivalent was in the range of $0.1{\sim}10mSv$. The participants assessed the results of their dosimeter readings in terms of the ICRU operational quantities for personal monitoring, Hp(10) and Hp(0.07). Most participants except 1 dosimeter estimated the delivered dose equivalent with biases less than ${\pm}25%$ for Cs-137 and Sr/Y-90. But for X-rays, the biases exceeded ${\pm}35%$ in some cases bacause the dose evaluation algorithm was based on the ANSI N13.11 X-ray fields which are different from those given by ISO.

• Journal of Radiation Protection and Research
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• v.22 no.3
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• pp.161-170
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• 1997

Theoretical and experimental determination of the lower limits of detection (LLD) of C-300-A $CaSO_4$:Dy TL dosimeters which are currently used for the personnel monitoring in Korea Atomic Energy Research Institute(KAERI) are described with a critical level which is defined as the signal level above which a result has a probability of being due to a fluctuation of the background. The personnel monitoring processors can derived easily the LLD of their system using this method with the background readings of their service interval and the irradiation readings of the known doses. Experimental studies were also conducted for the fading rates of the dosimeters with the temperatures and humidities for 3 months. Finally sensitivity changes in repeat uses were measured for 40 times consecutive uses of the dosimeters. The applications of the experimental results of fading rates and sensitivity changes in real personnel monitoring services are discussed briefly.

• Journal of Radiation Protection and Research
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• v.14 no.1
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• pp.66-70
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• 1989

In routine testing, the radioactive neutron sources are particularly suitable for producing standard. neutron fields. The ISO TC-85 has proposed neutron reference radiation for the calibration of neutron measuring devices used for radiation protection purposes. Radiation laboratory of KSRI has installed a standard irradiation facility using $^{252}Cf$ and $^{241}Am-Be$ sources for calibrating personal dosimeters according to the recommendations given in ISO TC-85. In this study, correction factors for calibration related to neutron scattering and anisotropy are obtained by experiments with commercial rem meter for demonstration purposes.

• Journal of Sensor Science and Technology
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• v.9 no.4
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• pp.274-280
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• 2000

This paper deals with an experimental study to apply commercial semiconductors to measure radiation dose rate for gamma ray. Since the low cost, small size, high efficiency and ruggedness of silicon photodiodes make them attractive photodetectors, they coulde be effectively used in measuring any radiation such as gamma ray. Most PN photodiodes show that the reverse current increases when the light is increased. Therefore the depletion region of them have influence on the reverse current, so we choose silicon PIN photodiodes with large depletion region. In order to detect radiation dose rate and then, to apply in developing any gamma ray dosimeter, some examinations and experiments were performed to PIN photodiodes in this work. Two kinds of PIN photodiodes, such as NEC's PH302 and SIEMENS's BPW34, were tested in a Co-60 gamma irradiation facility with a semiconductor parameter analyzer. As a result, we found that such PIN photodiodes present good linearity in diode current characteristics with dose rate. Therefore silicon PIN photodiodes could be suitably used in designing gamma ray dosimeters.

• Journal of Biomedical Engineering Research
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• v.38 no.5
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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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• v.53 no.9
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• pp.3035-3043
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• 2021

Epidemiological research has revealed that radiation exposure can cause cataracts. The Korean nuclear regulatory body has proposed the reduction of the occupational dose limit for the lens of the eye from 150 mSv/y to 100 mSv/5y, with an additional limitation of not exceeding 50 mSv/y for a specific year, taking into account the recommendations of the International Commission on Radiological Protection, and the International Atomic Energy Agency. This means that radiation workers should receive the same level of radiation safety for the lens of the eye as for whole-body protection. Korean nuclear power plants (NPPs) are conducting research to establish the radiation protection program for the lens of the eye. In terms of the preliminary results of the implementation of the radiation protection program for the lens of the eye dedicated to Korean NPPs, this review article summarizes the current state of understanding of the regulations, technical guidance, eye lens dosimeters, and radiation field conditions resulting in lens dose.

• Journal of the Korean Society of Radiology
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• v.13 no.3
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• pp.333-338
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• 2019

In the field of radiotherapy, the Quality Assurance(QA) procedure to verify the safety of treatment is considered to be very important. However, due to various problems of the conventional dosimeters used for the QA, researches on these dosimeters have been actively carried out to replace them. In this study, to maximize the sensitivity by visible light(VL) emitted from phosphors, blended hybrid sensors were fabricated by blending various weight percent(wt%) of $Gd_2O_2S:Tb$ which is a phosphor with excellent fluorescence efficiency into $PbI_2$. Then, the electrical properties to high energy radiation from the blended sensors and the pure $PbI_2$ sensor were compared and evaluated. As a result of the sensitivity evaluation, the sensor of 3wt% showed the highest value with more than 40% difference from the other sensors, and gradual decreasing in sensitivity was observed with increasing wt% except for the sensor of 3wt%. Also, in the reproducibility evaluation, the pure $PbI_2$ sensor exhibited a large variation in coefficient of variation(CV)>0.015, while all the blended sensors showed CV<0.015.

• Proceedings of the Korean Society of Medical Physics Conference
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• 2002.09a
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• pp.282-284
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• 2002

We have developed and used BISS as a radiation detector to verify patient dose and determine the physical characteristics of beams used in Stereotatic Radio Surgery(SRS) and Intensity Modulated Radiation Therapy(IMRT). In order to confirm the function and accuracy of our BISS, we simulate our measurements by BISS under the radiation of 6MV photons from a Varian Clinac 21EX equipped with a 60 leaf pairs MLC. For the simulation based on the Monte Carlo algorithm, which remains the most comprehensive and accurate theoretical method to verify beam profiles, we use the BEAM code. Compared with the measurements by BISS, our simulation of variously shaped phantom measurements show good agreements. Our simulation results can be used as a theoretical standard to compare and confirm measurements by BISS and other dosimeters such as ultramicro cylindrical ionization chamber(UCIC) and radiographic film.

• The Korean Journal of Pain
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• v.25 no.1
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• pp.16-21
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• 2012

Background: The C-arm fluoroscope is known as the most important equipment in pain interventions. This study was conducted to investigate the completion rate of education on radiation safety, the knowledge of radiation exposure, the use of radiation protection, and so on. Methods: Unsigned questionnaires were collected from the 27 pain physicians who applied for the final test to become an expert in pain medicine in 2011. The survey was composed of 12 questions about the position of the hospital, the kind of hospital, the use of C-arm fluoroscopy, radiation safety education, knowledge of annual permissible radiation dose, use of radiation protection, and efforts to reduce radiation exposure. Results: In this study, although most respondents (93%) had used C-arm fluoroscopy, only 33% of the physicians completed radiation safety education. Even though nine (33%) had received education on radiation safety, none of the physicians knew the annual permissible radiation dose. In comparing the radiation safety education group and the no-education group, the rate of wearing radiation-protective glasses or goggles and the use of radiation badges or dosimeters were significantly higher in the education group. However, in the use of other protective equipment, knowledge of radiation safety, and efforts to reduce radiation exposure, there were no statistical differences between the two groups. Conclusions: The respondents knew very little about radiation safety and had low interest in their radiation exposure. To make the use of fluoroscopy safer, additional education, as well as attention to and knowledge of practices of radiation safety are required for pain physicians.

• Journal of Veterinary Clinics
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• v.41 no.3
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• pp.157-164
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• 2024

The standard radiation protection method in the angiography suite involves the use of a thyroid shield, a lead apron, and lead glasses. However, exposure to substantial amounts of ionizing radiation can cause cataracts, tumors, and skin erythema. A newly developed curtain-type radiation protection device consists of a curtain drape composed of a five-layer bismuth and lead acrylic head-shielding plate, with both bearing an equivalent 0.25 mm lead thickness. In this study, a quality assurance phantom was used as the patient to create radiation scatter from the radiographic source, and an anthropomorphic mannequin phantom was used as the interventionalist to measure the radiation dose at seven different anatomical locations. Thermoluminescent dosimeters were used to measure the radiation dose. The experimental groups consisted of all-sided or one-sided curtain set-ups, the presence or absence of a conventional shielding system, and the orientation of beam irradiation. Consequently, the curtain-type radiation protection device exhibited better radiation protection range and capabilities than conventional radiation protection systems, especially in safeguarding the forehead, eyes, arms, and feet, with minimal radiation exposure. Moreover, the mean shielding ratios of the conventional shielding system and curtain-type radiation protection device were measured at 51.94% and 93.86%, respectively. Additionally, no significant decrease in the radiation protection range or capability was observed, even with changes in the beam orientation or one-sided protection. Compared with a conventional shielding system, the curtain-type radiation protection device decreased radiation exposure doses and improved comfort. Therefore, it is a potential new radiation protection device for veterinary interventional procedures.