• Journal of the Korean Society of Radiology
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• v.7 no.2
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• pp.113-120
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• 2013

Nowadays, the medical system towards patients changes into the medical services. As the human rights are improved and the capitalism is enlarged, the rights and needs of patients are gradually increasing. Also, based on this change, several systems in hospitals are revised according to the convenience and needs of patients. Thus, the cases of mobile portable among examinations are getting augmented. Because the number of mobile portable examinations in patient's room, intensive care unit, operating room and recovery room increases, neighboring patients are unnecessarily exposed to radiation so that the examination is legally regulated. Hospitals have to specify that "In case that the examination is taken out of the operating room, emergency room or intensive care units, the portable medical X-ray protective blocks should be set" in accordance with the standards of radiation protective facility in diagnostic radiological system. Some keep this regulation well, but mostly they do not keep. In this study, we shielded around the Collimator where the radiation is detected and then checked the change of dose regarding that of angles in portable tube and collimator before and after shielding. Moreover, we tried to figure out the effects of shielding on dose according to the distance change between patients' beds. As a result, the neighboring areas around the collimator are affected by the shielding. After shielding, the radiation is blocked 20% more than doing nothing. When doing the portable examination, the exposure doses are increased $0^{\circ}C$, $90^{\circ}C$ and $45^{\circ}C$ in order. At the time when the angle is set, the change of doses around the collimator decline after shielding. In addition, the exposure doses related to the distance of beds are less at 1m than 0.5m. In consideration of the shielding effects, putting the beds as far as possible is the best way to block the radiation, which is close to 100%. Next thing is shielding the collimator and its effect is about 20%, and it is more or less 10% by controlling the angles. When taking the portable examination, it is better to keep the patients and guardians far enough away to reduce the exposure doses. However, in case that the bed is fixed and the patient cannot move, it is suggested to shield around the collimator. Furthermore, $90^{\circ}C$ of collimator and tube is recommended. If it is not possible, the examination should be taken at $0^{\circ}C$ and $45^{\circ}C$ is better to be disallowed. The radiation-related workers should be aware of above results, and apply them to themselves in practice. Also, it is recommended to carry out researches and try hard to figure out the ways of reducing the exposure doses and shielding the radiation effectively.

• Journal of the Korea Concrete Institute
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• v.28 no.1
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• pp.59-65
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• 2016

Commercial synthetic resins with great amount of hydrogen atoms were investigated for neutron shielding aggregates. Total three types of resins were considered in this study: high density polyethylene (HDPE), polypropylene (PP), and ultra molecular weight polyethylene (UPE). When these resins replaced 20, 40, 60 vol% of fine aggregates, mechanical properties were first evaluated including compressive and tensile strengths, and then image/microstructure analyses such as cross-section analysis, SEM, and X-ray CT were performed. The results showed that the compressive and tensile strengths decreased with the increase of replacement ratio of HDPE and PP, which was found through image analysis that it was closely related to the distribution of resins at the failure surface of test specimens. The strength reduction of UPE was quite small compared to HDPE and PP but it abruptly increased when the replacement level exceeded 60 vol%. The results of microstructure analyses indicated that the replacement level significantly affected the amount of air void so that it is critical to determine the reasonable amount of UPE to make cementitous materials for neutron shielding.

• Journal of Radiation Industry
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• v.9 no.2
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• pp.69-75
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• 2015

Purpose: The gonad shielding is used to minimize the impact of the exposure to gonads when Abdomen, Pevis and Hip X-ray inspections are conducted on radiation impressionable pediatric patients. By the way, the gonad is palpable difficult and impossible to check visually because it's a sensitive area, so tests are conducted with the approximate location of shielding, thereby appearing problems of not shielding gonads accurately. Accordingly, this study produced shields by age and gender of pediatric patients and studied the method of positioning shields with ASIS as a reference point without palpable sensitive areas, and tried to evaluate its usability. Materials and methods: The study surveyed 30 pediatric patients by gender and age, who came and got inspected in Department of Radiology, our hospital from February 2012 to January 2014 and obtained the value of tolerance by measuring the average size of the pelvis using the distance measurement function of Infinitt Piview with the images stored in the PACS and producing shields by age and gender of pediatric patients and specifying the areas at random for the comparative analysis of pre- and post-using. It calculated the technology statistics($mean{\pm}SD$) with the value of tolerance measured the length using SPSS 12.0 statistical program. Results: As for boys, differences in the tolerance range of pre- and post-using shields were 2.69 mm in case of 1 year old, 2.58 mm in 2 years, 2.37 mm in 3 years, 2.815 mm in 4~5 years, 2.043 mm in 7~10 years, and as for girls, 1.92 mm in 1~2 years, 1.75 mm in 3~4 years, 2.52 mm in 5~6 years and 1.93 mm in 7~10. After analyzing the pre- and post-using shields for all of boys and girls, there were statistically significant differences(P<0.050). Conclusions: It is considered that we can minimize the exposure to gonads and get a better video for diagnosis in testing high biological impressionable pediatric, if we use shields correctly with ASIS as a reference point considering its shape and size by age and gender in Abdomen, Pevis and Hip X-ray inspections.

• Journal of the Korean Society of Radiology
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• v.11 no.4
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• pp.189-195
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• 2017

Radiation protection equipment has widely used to protect human body from radiations, for example X-ray and gamma ray. The material of the radiation protection equipment is mainly lead (Pb) which has brought out lead poisoning and pollution when the equipment is fallen into disuse. This problem makes research and development find new Pb-free materials for use of radiation protection. Manufacturing and evaluation processes for developing those material were carried out repletely until obtaining the performance of protection rate. In this study, combination possibility of shielding material was studied using Geant4 monte carlo simulation. X-ray tube under the same condition in the real measurement of the protection rate was simulated, and X-ray tube spectrum was obtained. The X-ray tube spectrum was applied to study on the protection rate and lead equivalent. The porosity effect was simulated, and was one of key factors to determine protection rate or lead equivalent in radiation protection sheet of Pb-free.

• Journal of radiological science and technology
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• v.38 no.3
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• pp.199-203
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• 2015

Panoramagraphy was the second most used intraoral radiography utilized in Korea, resulting in 17.8% in university dental hospitals, 24.8% in dental hospitals, and 31.4% in dental clinics. Depending on increased demand like orthodontics and implant, panoromagraphy tends to consistently increase. This study were used lead glasses and lead shielding to reduce unnecessary radiation to the eyeballs and thyroid. ESD was 41.4% when radiation was shielded with the lead glasses while reducing 47.3% of ESD by shielding the X-ray tube area with shielding lead. There was no statistically significant difference. The lead glasses is appropriated to reduce unnecessary radiation exposure to the eyeballs.

• Journal of Powder Materials
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• v.22 no.4
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• pp.234-239
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• 2015

Electronic products are a major part of evolving industry and human life style; however most of them are known to emit electromagnetic waves that have severe health hazards. Therefore, different materials and fabrication techniques are understudy to control or limit transfer of such waves to human body. In this study, nanocomposite powder is dispersed into epoxy resin and shielding effects such as absorption, reflection, penetration and multiple reflections are investigated. In addition, nano size powder (Ni, $Fe_2O_3$, Fe-85Ni, C-Ni) is fabricated by pulsed wire evaporation method and dispersed manually into epoxy. Characterization techniques such as X-ray diffraction, Scanning electron microscopy and Transmission electron microscopy are used to investigate the phase analysis, size and shape as well as dispersion trend of a nano powder on epoxy matrix. Shielding effect is measured by standard test method to investigate the electromagnetic shielding effectiveness of planar materials, ASTM D4935. At lower frequency, sample consisting nano-powder of Fe-85%Wt Ni shows better electromagnetic shielding effect compared to only epoxy, only Ni, $Fe_2O_3$ and C-Ni samples.

• Nuclear Engineering and Technology
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• v.25 no.1
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• pp.51-62
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• 1993

A computational program ［TDET］ of the particle transport equation is developed on radiation shielding problem in two-dimensional cartesian geometry based on the discrete element method. Not like the ordinary discrete ordinates method, the quadrature set of angles is not fixed but steered by the spatially dependent angular fluxes. The angular dependence of the scattering source term in the particle transport equation is described by series expansion in spherical harmonics, and the energy dependence of the particles is considered as well. Three different benchmark tests are made for verification of TDET : For the ray effect analysis on a square absorber with a flat isotropic source, the results of TDET calculation are quite well conformed to those of MORSE-CG calculation while TDET ameliorates the ray effect more effectively than S$_{N}$ calculation. In the analysis of the streaming leakage through a narrow vacuum duct in a shield, TDET shows conspicuous and remarkable results of streaming leakage through the duct as well as MORSE-CG does, and quite better than S$_{N}$ calculation. In a realistic reactor shielding situation which treats in two cases of the isotropic scattering and of linearly anisotropic scattering with two groups of energy, TDET calculations show local ray effect between neighboring meshes compared with S$_{N}$ calculations in which the ray effect extends broadly over several meshes.eshes.

• Korean Journal of Digital Imaging in Medicine
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• v.11 no.2
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• pp.85-92
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• 2009

This study, "The study about performance evaluations of mobile cover for X-ray's diffusion and distribution in mobile radiation" is based on the rules of mobile defense apparatus for radiation producer in 2006. To use the mobile cover for X-ray for diagnosis has been compulsory in common wards except operation rooms, emergency rooms and intensive care units. we have confirmed the effect in arbitrary shielding material after Qualitiy Control was carried out for accuracy in an experiment of mobile photographing equipment. The performance evaluation was conducted with the fabrics of selenium, 0.2 mmPb, 0.1 mmPb and aluminiums. Considering the result, we choosed 0.1 mmPb and attached cover to mobile photographing equipment. We have finished making the cover after drew up the draft to attach cover to mobile photographing equipment through the modeling and the structural analysis. the process of the study is that we assembled the manufactured structures and carried out the practical experiment to take the photograph after attaching the fabric of 0.1 mmPb to mobile photographing equipment. It is need of additional thesises hereafter that we compare the result between the part to improve for safety besides convenience in photographic experiment about clinical radiation and the effect of covering the diffusion in condition attached the cover.

• Journal of radiological science and technology
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• v.43 no.3
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• pp.169-176
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• 2020

Interventional radiology is performed under real-time fluoroscopy, and patients are exposed to a wide range of exposures for a long period of time depending on the examination and procedure. However, studies on radiation protection for patients during an intervention are insufficient. This study aims to evaluate the doses exposed during the intervention and the applicability of 3D printing materials. The organ dose for each intervention site was evaluated using a monte carlo simulatio. Also, the dose reduction effect of the critical organs was calculated when using a shielding device using 3D printing materials. As a result, the organ dose distribution for each intervention site showed a lower dose distribution for organs located far from the x-ray tube. It was analyzed that the influence of scattered rays was higher in the superficial organs of the back of the human body where x-rays were incident. The dose reduction effect on the critical organ using the 3D printing shield showed the highest testis among the gonads, and in the case of other organs, the dose reduction effect gradually decreased in the order of the eye, thyroid, breast, and ovary. Accordingly, it is judged that the 3D printed shield will be sufficiently usable as a shielding device for the radiation protection of critical organs.

• Journal of radiological science and technology
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• v.40 no.1
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• pp.41-47
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• 2017

Considering that the X-ray apron used in the department of radiology is also used in the department of nuclear medicine, the study aimed to analyze the shielding rate of the apron according to types of radioisotopes, thus ${\gamma}$ ray energy, to investigate the protective effects. The radioisotopes used in the experiment were the top 5 nuclides in usage statistics $^{99m}Tc$, $^{18}F$, $^{131}I$, $^{123}I$, and $^{201}Tl$, and the aprons were lead equivalent 0.35 mmPb aprons currently under use in the department of nuclear medicine. As a result of experiments, average shielding rates of aprons were $^{99m}Tc$ 31.59%, $^{201}Tl$ 68.42%, and $^{123}I$ 76.63%. When using an apron, the shielding rate of $^{131}I$ actually resulted in average dose rate increase of 33.72%, and $^{18}F$ showed an average shielding rate of -0.315%, showing there was almost no shielding effect. As a result, the radioisotopes with higher shielding rate of apron was in the descending order of $^{123}I$, $^{201}Tl$, $^{99m}Tc$, $^{18}F$, $^{131}I$. Currently, aprons used in the nuclear medicine laboratory are general X-ray aprons, and it is thought that it is not appropriate for nuclear medicine environment that utilizes ${\gamma}$ rays. Therefore, development of nuclear medicine exclusive aprons suitable for the characteristics of radioisotopes is required in consideration of effective radiation protection and work efficiency of radiation workers.