• Progress in Medical Physics
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• v.24 no.2
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• pp.119-126
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• 2013

Due to the introduction of CR and DR, it has been neglected the use of the X-ray beam collimator and field size. This study examines nationwide survey of the proper use of collimator and field size by area in a specific field of plain radiography and the current status. Authors emphasized the need for the field size criteria, and propose a standard reference field size in each specific radiologic examination. Total 333 medical institutions (included in Seoul, Gyeonggi-do, Jeolla, Chungcheong, Gangwon-do, Busan area), were investigated in relation to the status of the X-ray beam collimation field size, type specific inspection areas, medical facilities, and image analyses by type to figure out whether they use the adjustment of image field to the specific examination. To assess the awareness and the impact of radiation exposure to the collimation adjustable, 168 radiographers who was working in 10 general hospitals, 10 hospitals, and 10 clinics, were surveyed how they haver adjusted the actual field size. We examine that 61.3% of medical institutions used the "Proper collimation" and only 49.9% of them employed proper one in lumbar spine densely crowded by major organs. 69% among general hospitals, and 65% among hospitals using DR system were using proper collimation. Radiographers recognized that proper adjustment of collimation could reduce the harmful radiation dose on patients. In the survey, 97.6% of respondents were aware of this fact, but only 83.3% of respondents did the adjustment of the size of the collimation field. The using of proper collimation field was low in the nationwide survey, so the effort to reduce the radiation dose on the patients is urgently needed. A unified standard for the field accompanied by thorough education should be needed.

• Journal of radiological science and technology
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• v.20 no.2
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• pp.49-55
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• 1997

This study was carried out to investigate radiographical and operating conditions of X-ray units and exposure doses to patients during chest radiography, so that the results could provide basic data used for reducing the exposure dose and for providing the diagnostic information with better quality. The conditions and exposure doses of 100 X-ray units mainly used for chest radiography were examined and also 100 radiological technologists mainly handling those apparatus at 76 medical facilities in Pusan were surveyed using a questionnaire from October 1 to December 31 in 1995. The following results were obtained from the study : 1. It was found that most units were capable of taking a high tube voltage radiography by showing 67% of the units equipped with the maximum tube voltage of 150 kV, 94% with more than 500 mA for the rating capacity and 85% with the full wave type of a signal phase. 2. For actual chest radiographical conditions, however, 80% of the units were operated at $60{\sim}100\;kVp$ and only 14% at 100 kVp and over for the high tube voltage. 3. The average exposure time was less than 0.1 second, and eighty four percent of the units adapted the X-ray tube currents ranging from 200 to 300 mA, 80% the focus-film distances between 180 and 210 cm, and 63% the focus sizes of more than 2.0 mm. 4. Most units(98%) employed additional filters made of aluminum, 75% the thickness of filters less than 2.0 mm, and only 2 units the compound filters. 5. Ortho chromatic system was only adopted in 13% of screen film system for the units, and 73% used the grid ratio at 8 : 1 for the low tube voltage during chest radiography. 6. The average exposure dose of all X-ray units during chest radiography was $371\;{\mu}Sv$ with a difference of about 16 times between the minimum to the maximum, and $386\;{\mu}Sv$ both at hospitals and at health centers, followed by $380\;{\mu}Sv$ at general hospitals and $263\;{\mu}Sv$ at university hospitals without showing any statistically significant differences. In conclusion, since patients during chest radiography at medical facilities in Pusan exposed to high levels of radiation, it is recommended that appropriate added filters and grids necessary for the high tube voltage radiography and high-speed screen systems should be adopted and used as soon as possible in order to reduce exposure dose to the patients.

• Journal of radiological science and technology
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• v.41 no.5
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• pp.493-504
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• 2018

The diagnostic radiation equipment is managed in accordance with the "Rules for Safety Management of Diagnostic Radiation Equipment" enacted in 1995. The equipments should be inspected before use and every three years after use in accordance with the [Appendix 1] of the same rule. The inspection standard has been maintained without particular revision since enacted. But, over the past two decades new types of equipments have been manufactured and used. So, it is necessary to revise [Appendix 1] by making inspection items and inspection standards. In this study, we revised the classification system of equipments and reviewed international standards of IEC 60601 series, IEC 61223 series and AAPM TG 18 On-line Report No.03. And identified the problem of current inspection standards. Through this, we revised, deleted and added the inspection items and inspection standard of each equipment to meet the domestic circumstances. As a result of the study, we reorganized the classification system of equipment which are current classified as 5 classes into 22 classes as X-ray system etc. (7 classes), CT system etc. (5 classes) and Dental X-ray system etc. (10 classes). And then, we developed 70 inspection items for 6 types of equipments according to the reorganized classification system of equipments. The inspection items and inspection standards derived from this study have been proposed to the KCDC and will be applied to the revision of the Rule's [Appendix 1]. Therefore, we expect to be used as reference materials for domestic medical center, inspection institutions, and equipment manufacturing import companies.

• Journal of radiological science and technology
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• v.18 no.2
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• pp.49-59
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• 1995

Recently, general radiography became to variety because of the continuous development of Inverter type generator and ortho chromatic system. Therefore, we must re-evaluate about patient exposure dose and image quality. I studied about chest radiography which has frequency among general radiography being used during FEB. to AUG., 1994 over 151 medical facilities from medical facilities that are located in Seoul area. The result obtained were as follows ; 1) The rectification method of the generator were employing mainly single phase full wave in 82.8 %, three phase full wave in 11.26 % and Inverter type in 4.64 % and condenser type is 1.32 %. 2) Exposure kV was used below 80 kV in most medical facilities and 21.8 % of the medical facilities was using high tube voltage higher than 120 kV. 3) The exposure time was used below the 0.05 sec in 28.4 %, in 29.8 % of the medical facilities used above 0.1 sec. 4) The usage frequency of the added filter is 15.3 %, and among them compound filter was used only 4 %. 5) Rare earth screen was used in 37.7 %. 6) The average skin entrance dose was 0.25 mSv, the range of dose is $0.05{\sim}0.79\;mSv$ in each medical facilities. 7) The average density of the lung field is 1.76, 0.49 in lung side, 0.30 in mediastinum and 0.37 in heart shadow. Therefore it is required to improve all of these for increasing image quality and reducing patient exposure dose as soon as possible.

• Journal of the Korean Ceramic Society
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• v.12 no.1
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• pp.29-36
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• 1975

This study was conducted to research the formation, color development and application for colored glazes of the spinel solid solutions of the green pigment. On specimens prepared by calcining the oxide and basic carbonate mixture at 1250℃ for 1.5 hour, the x-ray analysis, measurement of reflectance and the test of their stabiality as a glaze pigment were carried out. The results are summarized as follows 1) Each sample is composed of single spinel and not of mixture of spinel. 2) Formation of continuous soild solution, except for a few instances, pertaining to Vegard's law was confirmed by means of the x-ray analysis. 3) The more difference between absorption and reflectance lies, the lighter colors are. When the absorption occurs at the high-reflectance, the excitation purity becomes low. On the contrary when the absorption takes place at the low-reflectance, the excitation purity becomes low. On the contrary when the absorption takes place at the low-reflectance, the excitation purity is higher. 4) Colors obtained in the CdO-MgO-Cr2O3-Al2O3 system, as the amounts of Al3+ increased, change from green through brown to pink, and the absorption peak shifts towards violet region. 5) An increase in Co2+ in the CoO-MgO-Cr2O3-Al2O3 system, changes the color from blue green to dark blue. The excitation purity is higher, and the absorption peak shifts toward regions. 6) Colors are green in the NiO-MgO-Cr2O3 and CdO-MgO-Cr2O3 systems in general, but in the ZnO-MgO-Cr2O3 system brillant hue is not obtained. 70 According to the results of the colored glaze test, the spinels turn outto be stable as brilliant glaze pigment in the calcium-magnesia glaze.

• Conservation Science in Museum
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• v.21
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• pp.53-66
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• 2019

This study describes the processes undertaken for the conservation treatment of metal artifacts excavated in Hasong-ri, Yeongwol, Gangwon-do and the results of the related surface composition analysis. X-ray fluorescence analysis (XRF) was applied to analyze the surface composition of a small gilt-bronze wind chime, two clappers, and a small gourd-shaped bronze bottle. The gourd-shaped bronze bottle was investigated using radiography to examine its internal structure. The wind chime and clappers were excavated from the same location. A gilt layer was identified on the wind chime, but surface corrosion made it difficult to identify any such layers on the clappers. The element analysis revealed that the wind chime was made of bronze in a Cu-Sn-Pb ternary system and was gilt-plated using mercury amalgam. The clappers were made from copper with a small amount of gold detected, but did not show any evidence of mercury. Since a thick corrosion layer was affixed to the surface of each clapper, it was impossible to identify the surface composition and determine if the clappers had been gilded. It is possible that the gold detected from the clappers was a foreign substance or had detached from the giltbronze wind chime buried alongside them. The small gourd-shaped bronze bottle was investigated through surface element analysis and radiography to verify if it was a type of silver bottle used as currency during the Goryeo dynasty. The radiography photography identified that a small hole in the middle of the base had been stopped up. The general surface analysis did not detect silver, which suggests that the bottle was made of bronze instead and was not one of the silver bottles used as a means of currency.

• Journal of Digital Convergence
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• v.12 no.12
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• pp.371-379
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• 2014

In this study, we conducted a survey on the limited examinations of the DR system to the 30 radiologic technologists engaging in the clinical sites and university hospitals in Daejeon metropolitan city from Oct. 15, 2012 to Nov. 15, 2012. Based on the survey results, we propose the conceptual design of a supplementary table for the conventional DR system to extend the examination capability and overcome the limitation of DR system. And, we evaluated the convenience and usefulness of the proposed table by applying it to five subjects. Ten experts were involved to evaluate the clinical usefulness of the obtained images. In this study, the experimental results show the feasibility to overcome the limited examination of the conventional DR system, and the proposed supplementary table may be beneficial to patients and hospitals.

• The Korean Journal of Ceramics
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• v.6 no.2
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• pp.164-167
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• 2000

The barium rich region of the Y-Ba-Cu-O-C system includes a tetragonal perovskite-like phase, which possesses a wide homogeneity region toward yttrium, copper and carbonate ion on the one hand, and toward oxygen, on the other hand. Accounting for vacancies ($\square$-vacancy) this phase could be described by the general formula per unit cell: {Ba$_8$}[Y$_{3-z}$Cu$_{5-x}$$(CO_3)_n$ $\square$$_{x+x-n}$]O$_{y{\pm}{\delta}y}$ (*). Here, cube-octahedral sites are represented in braces, while quasioctahedral ones with proper octahedral (Y, Cul), square (Cu2) and triangular (CO$_3$) configuration are shown in square brackets. The formula (*) was confirmed by full-profile Rietveld refinement based on X-ray diffraction data of YBa$_{5}$Cu$_2$O$_y$ (1-5-2 phase). Homogeneity region limits of the phase (*) at 96$0^{\circ}C$ in air were determined to be -0.33$\leq$x$\leq$1.80, 0.33$\leq$z$\leq$2.00, 0$\leq$n$\leq$3.

• Journal of Korean Academy of Nursing
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• v.27 no.3
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• pp.563-576
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• 1997

This study was carried out to identify basic data for more efficient operation of comprehensive health check-up centers in the national health care system. The researcher reviewed and analyzed the main symptoms of the subjects according to sex, age, occupation and positive rate in the screening tests of a comprehensive health check-up, performed at one comprehensive health check-up center in located in a hospital. The subjects were 512 persons who had a check-up at the comprehensive health check-up, center in K university hospital in Seoul from October 2, 1996 to March 30, 1997. A questionaire developed by the researcher to obtain subject's general characteristics, main symptoms, medical examination, diagnosed disease was used as the tool for the study. The researcher analyzed the data with SPSS PC/sup +/ program. : the distribution of the subject's general characteristics and main symptoms was described with percentages and the difference between main symptoms and screening tests analyzed with X²-test, t-test, ANOVA. The result of this study are as follows : 1. For the distribution of diagnosis in males. liver disease was most frequent and hypertension was second : in females, hypertention and liver disease were not common in that order. 2. The most common complaints were indigestion in the digestive system, sputum in the respiratory system, irregular heart beat in the cardiovascular system, frequent urine in the urinary system vertigo in the hematologic system. 3. The main symptoms according to sex were for females, a statistically siguificant higher rate of complaints in the digestive system, cardiovascular system, urinary system, hematologic system, musculoskeletal, mental & nervous system as compared to males. 4. The main symptoms according to age were that in the the second decade there wara higher rate of complaints in the digestive system, and cardiovascular system than in the older age groups : and in the fifth decade more in the musculoskeletal system. 5. The main symptoms according to occupation were that formers and fishers had a higher rate of complaints in the mental and nervous system as compared to other occupation groups : and office workers, in gynecology. 6. The main symptoms according to diagnosis, were symptoms of the digestive system, frequent in liver disease : symptoms of the cardiovascular system in allergic disease. 7. The screening tests which showed the highest rates were UGI /FGS, PFT : In males a higher rate of abnormality was seen in abdominal ultrasono- graphy and in, females, in mammography. 8. In screening tests according to sex, males showed a higher positive rate for chest X-rays, and LFT, and females, in mammography, pap smear, CBC. 9. In screening tests according to age, higher positive rates of obesity, high blood pressure, chest X-ray, mammography, pap smear, FBS, CBC, urine test were seen in the fifth decade : PFT and abdominal ultrasonography in the third decade. The subjects who wanted comprehensive health check-up were not asymptomatic but had an illness with several symptoms. It is found that the most frequent diagnosed diseases were hypertention and liver disease. So proper observations must be done for them. Comprehensive health check-ups should be changed to a comprehensive examination including treatment beyond examination for those subjects with positive results.

• Journal of the Korean Chemical Society
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• v.37 no.11
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• pp.923-928
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• 1993

The series of solid solutions in the $Sr_{1+x}Ho_{1-x}FeO_{4-y}$ (x = 0.00, 0.25, 0.50, 0.75 and 1.00) systems with $K_2NiF_4$ type structure have been prepared at 1550$^{\circ}$C under an atmospheric air pressure. The X-ray powder diffraction spectra of these samples assign that the crystallographic phases are tetragonal system over the whole x range. The lattice volume was increased with increasing the substitution amount of the $Sr^{2+}$ ion. The mole ratio of the $Fe^{4+}$ ion to total iron ions or ${\tau}$ value has been determined by Mohr salt titration of the sample and then the y value was calculated from x and ${\tau}$ values. The ${\tau}$ and y values have been increased with x values. The nonstoichiometric chemical formula are formulated from the general formula of $Sr_{1+x}Ho_{1-x}Fe^3_{1-}\;^+_{\tau}Fe_{\tau}^{4+}O_{4-y}$ replaced by x,${\tau}$ and y values. Mossbauer spectra show the mixed valence state and coordination state of $Fe^{3+}\;and\;Fe^{4+}$ ions. It is found out that the magnetic property of the samples is paramagnetic at room temperature. Electrical conductivity varied within the semiconductivity range of 1.0 to 1 ${\times}\;10^{-9}{\Omega}^{-1}cm^{-1}$. Activation energy of the electrical conductivity was decreased with the $\tau$ value. The conduction mechanism should be explained by the hopping model of the conduction electrons between the valence states of $Fe^{3+}\;and\;Fe^{4+}$ ions.