• Journal of the Korean Society of Radiology
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• v.16 no.4
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• pp.373-379
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• 2022

The radiation source used for non-destructive testing have permeability and cause a scattered radiation through collisions of surrounding materials, which causes changes in the surrounding spatial dose. Therefore, this study attempted to evaluate and analyze the distribution of spatial dose by source in the working environment during the non-destructive test using monte carlo simulation. In this study, Using FLUKA, a simulation code, simulates ⁶⁰Co, ¹⁹²Ir, and ⁷⁵Se source used in non-destructive testing, The reliability of the source term was secured by comparing the calculated dose rate with the data of the Health and Physics Association. After that, a non-destructive test in the radiation safety facility(RT-room) was designed to evaluate the spatial dose according to the distance from the source. As a result of the spatial dose evaluation, ⁷⁵Se source showed the lowest dose distribution in the frontal position and ⁶⁰Co source showed a dose rate of about 15 times higher than that of ⁷⁵Se and about 2 times higher than that of ¹⁹²Ir. In addition, the spatial dose according to the distance tends to decrease according to the distance inverse square law as the distance from the source increases. Exceptionally, ⁶⁰Co, ¹⁹²Ir, and ⁷⁵Se sources confirmed a slight increase within 2 m of position. Based on the results of this study, it is believed that it will be used as supplementary data for safety management of workers in radiation safety facilities during non-destructive testing using radioactive isotopes.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2012.05a
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• pp.876-879
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• 2012

In this paper we studied the radiation detection technology which described the radiation level distribution in high radiation area with remotely and safely. The designed radiation mapping system was composed of radiation nodes and radiation station. The radiation nodes could sense the radiation dose values with pMOSFET radiation sensors and transmit them to the radiation station. At the radiation station the received radiation values were merged with a geometric information and visualized at the virtual graphic location. For the functional verification of the above system, we attached the radiation nodes to each corner in our laboratory, executed the mapping tests, and confirmed the designed functions finally.

• 대한방사선방어학회:학술대회논문집
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• 2009.04a
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• pp.106-107
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• 2009

• The Journal of the Korea Contents Association
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• v.12 no.12
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• pp.694-701
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• 2012

This study set put to measure the environmental radiation for mountainous regions of National Parks where Integrated Environmental Radiation Monitoring Network is not installed. For the measurement method, the space dose was classified at 1 meter high from the surface and the index dose at the surface. The measured radiation energy measured gamma, alpha and beta rays. For selection of national parks, we selected 10 national parks which are within the same distribution in the southern part and central part of the nation. For measurement equipment, INTERCEPTOR$^{TM}$(Thermo, USA, 2006) was used for gamma rays. As for the results of the measurements, for the space gamma dose, a high level was measured at a sea level of 500 meter in national parks with an altitude of less than 1,000 meter. It was found that the value was more than $0.23{\mu}Svh^{-1}$ especially in Bukhan Mountain, Gyeryong Mountain and Wolchul Mountain. In national parks with an altitude of more than 1,000 meter, $1.77{\mu}Svh^{-1}$ was measured at 1,500 meter at Seorak Mountain. Therefore, this is 10 times greater than the background standard dose. The national parks were there were no significant changes in dose were Naejang Mountain, Sobaek and Jiri Mountains. For the measurement of the index dose, a high dose level was measured at middle altitudes of 500 meter and 1,000 meter. For measurement according to the composition types of crust, high doses were recorded at national parks composed of rocks and a lower environmental radiation level was measured at Hanra Mountain where volcanic activities have occurred.

• The Journal of the Korea Contents Association
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• v.15 no.11
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• pp.298-306
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• 2015

This study is the material of the additional filter(Cu, Ni, CaWO4, Gd+Ba) being used when the diagnosis X-ray was varied to evaluate the spatial dose distribution accordingly. And it suggest to find a suitable material. Experiments using MCNPX program based on the Monte Carlo simulation method was carried out by selecting the chest and abdomen taken. As a result, each material per dose, the average scatter dose is approximately 62%, 100 cm radius of the point of the simulated body surface exposure dose and 50 cm radius centered on the point average about 47%. It is determined that an Al material is currently available in accordance with the result to be replaced by Cu, Ni material is sufficient. With just the thickness due to the difference in the atomic number and density adjusted to be about one-tenth of the Al it will be suitable.

• Journal of the Korean Society of Radiology
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• v.7 no.1
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• pp.45-50
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• 2013

Non-invasive technique CT, called automated computed tomography, is used to detect lesion of a patient when diagnosing human body. Information obtained from CT plays an important role in assembling 3 dimensional images. Recently, new equipment, operated by CT, is required which can be appliable to physical and biological research. In accordance to this quest, micro-CT is invented that produce more detail and concrete information. Images supplied by CT are even more detailed and concrete, so it contributes much to the development of biology and polymer material engineering field. However, there has been little reliable reports regarding measuring information of space dose distribution about exposure dose limit of users operating micro-CT. In addition, little reports regarding space dose distribution of exposure has been known about unwanted diffraction light produced by usage of micro-CT. The exterior of micro-CT is covered by lead, which is for removing exposure of diffraction light. Thus, even if it is good enough to prevent exposure of diffraction light, consistent management of equipment will be required as time goes by and equipment are getting old as well. We measured space dose distribution regarding exposure of diffraction light of users operating micro-CT directly. Therefore, we suggest that proper management should be necessary for users operating micro-CT not to be exposed by unwanted diffraction light.

• Journal of radiological science and technology
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• v.39 no.2
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• pp.237-246
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• 2016

This study is therefore aimed at measuring the surface dose rate and the spatial dose rate in and outside the radionuclide facility in order to ensure safety of the patients, radiation workers and family care-givers in their use of such equipment and to provide a basic framework for further research on radiation protection. The study was conducted at 4 restrooms in and outside the radionuclide facility of a general hospital in Incheon between May 1 and July 31, 2014. During the study period, the spatial contamination dose rate and the surface contamination dose rate before and after radiation use were measured at the 4 places-thyroid therapy room, PET center, gamma camera room, and outpatient department. According to the restroom use survey by hospitals, restrooms in the radionuclide facility were used not only by patients but also by family care-givers and some of radiation workers. The highest cumulative spatial radiation dose rate was 8.86 mSv/hr at camera room restroom, followed by 7.31 mSv/hr at radioactive iodine therapy room restroom, 2.29 mSv/hr at PET center restroom, and 0.26 mSv/hr at outpatient department restroom, respectively. The surface radiation dose rate measured before and after radiation use was the highest at toilets, which are in direct contact with patient's excretion, followed by the center and the entrance of restrooms. Unsealed radioactive sources used in nuclear medicine are relatively safe due to short half lives and low energy. A patient who received those radioactive sources, however, may become a mobile radioactive source and contaminate areas the patient contacts-camera room, sedation room, and restroom-through secretion and excretion. Therefore, patients administered radionuclides should be advised to drink sufficient amounts of water to efficiently minimize radiation exposure to others by reducing the biological half-life, and members of the public-family care-givers, pregnant women, and children-be as far away from the patients until the dose remains below the permitted dose limit.

• The Journal of Korean Society for Radiation Therapy
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• v.19 no.1
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• pp.7-17
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• 2007

Purpose: As increasing complexity of modern radiotherapy technique, more developing dosimetry is required. Polymer gel dosimeters offer a wide range of potential applications with high resolution and assured quality in the thee-dimensional verification of complex dose distribution such as intensity-modulated radiotherapy (IMRT). The purpose of this study is to find the most sensitive and suitable gel as a dosimeter by varying its composition ratio and its condition such as temperature during manufacturing. Materials and Methods: Each polymer gel with various ratio of composition was irradiated with the same amount of photon beam accordingly. Various polymer gels were analyzed and compared using a dedicated software written in visual C++ which converts TE images to R2 map images. Their sensitivities to the photon beam depending on their composition ratio were investigated. Results: There is no dependence on beam energy nor dose rate, and calibration curve is linear. Conclusion: The polymer gel dosimeter developed by using anti-oxidant in this study proved to be suitable for dosimetry.

• Journal of the Korean Society of Radiology
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• v.7 no.3
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• pp.251-257
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• 2013

Spatial dose rates of high dose $^{131}I$ therapy patients were Measured Three dimensional (X, Y, Z) distributions. I have constructed geometrical an aluminum support structure for spatial dose meters placed in 5 different heights, 8 different azimuthal angles, 6 different time interval and distance 100 cm from High dose$^{131}I$ therapy patients. when the height of vertical plane Spatial dose distribution is 100 cm, the Spatial dose rates is max and the error range is low. the vertical plane Spatial dose rates was found to be 71.85 ${\mu}Sv/h$ on the average at a distance of 100 cm, height 100 cm, from the patients 24 hours after $^{131}I$ oral administration. I divided 12 patients into two groups. I have analysed group A (drinking 5 L water) and group B (drinking 3 L water) in order to measure decrease spatial dose rates. I have found the spatial distributions of patient dose rates is $44.9{\pm}7.2$ ${\mu}Sv/h$ in group A and $100.3{\pm}8.1$ ${\mu}Sv/h$ in group B by 24 after $^{131}I$ oral administration. the reduction factor was found to be approximately 54 % through drinking 5 L water during 24 hours.

• Journal of dental hygiene science
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• v.15 no.3
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• pp.254-258
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• 2015

To compare the stationary dental X-ray generator and the portable dental X-ray generator and to understand spatial radiation dose depended on locations by measuring spatial radiation dose of the portable dental X-ray generator. The researchers used an Ionization chamber to measure spatial radiation dose which was generated while applying X-ray radiation to real bone skull phantom with both portable and stationary dental X-ray generator. There were 4 measurement locations which were immediate anterior, right, left and posterior. Distance of measurement was 50 cm in every location and the recorded result is an average of two applications of X-ray radiation to the maxillary molar area under the condition of 70 kVp, 3 mA, 0.1 sec. Average spatial radiation dose of portable X-ray generator was $37.51{\mu}Sv$, much higher than that of stationary X-ray generator which was $10.77{\mu}Sv$ (p<0.001). The result of the spatial radiation dose of the portable X-ray generator showed a huge difference depending on types of units which varied from $17.77{\mu}Sv$ to $68.90{\mu}Sv$ (p<0.05), also depending on the measurement location, immediate anterior resulted in the highest radiation dose of $54.14{\mu}Sv$ and immediate right was the lowest of $13.60{\mu}Sv$. Immediate left and posterior, however, resulted in similar radiation dose which were $42.12{\mu}Sv$, $40.18{\mu}Sv$ (p<0.01). With this result, we claim that usage of portable dental X-ray generator should be restricted to patients who can't move and exposure to radiation should be minimized by wearing lead-apron.