• Journal of radiological science and technology
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• v.38 no.1
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• pp.1-6
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• 2015

Whole spine scanography (WSS) is a radiological examination that exposes the whole body of the individual being examined to x-ray radiation. WSS is often repeated during the treatment period, which results in a much greater radiation exposure than that in routine x-ray examinations. The aims of the current study were to evaluate the patient dose of WSS using computer simulation, image magnification and angulation of phantom image using different patient position. We evaluated the effective dose(ED) of 23 consecutive patients (M : F = 13:10) who underwent WSS, based on the automatic image pasting method for multiple exposure digital radiography. The Anterior-Posterior position(AP) and Posterior-Anterior position( PA) projection EDs were evaluated based on the PC based Monte Carlo simulation. We measured spine transverse process distance and angulation using DICOM measurement. For all patient, the average ED was 0.069 mSv for AP position and 0.0361 mSv for PA position. AP position calculated double exposure then PA position. For male patient, the average ED was 0.089 mSv(AP) and 0.050 mSv(PA). For female patient, the average ED was 0.0431 mSv(AP) and 0.026 mSv(PA). The transverse process of PA spine image measured 5% higher than AP but angulation of transverse process was no significant differences. In clinical practice, just by change the patient position was conformed to reduce the ED of patient. Therefor we need to redefine of protocol for digital radiography such as WSS. whole spine scanography, effective dose, patient exposure dose, exposure direction. protocol optimization.

• Journal of the Korean Society of Radiology
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• v.14 no.4
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• pp.425-431
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• 2020

When a radiation generating device is installed in an export container due to COVID-19, the purpose of this study was to measure the space dose in the radiation room and to study the effectiveness of the shielding wall in the laboratory. Air dose measurement method was set behind the X-ray tube, 50 cm, 100 cm, 200 cm, and measured 12 locations. The dose values before and after the use of the movable radiation shielding wall were compared by measuring 3 locations behind the X-ray tube using the movable radiation shielding wall. The measured values were 50 cm on the left behind the X-ray tube: 1.446 μSv, behind the X-ray tube: 0.545 μSv, and 50 cm on the right behind the X-ray tube: 1.466 μSv. Measurements behind the radiation barrier were 0.190 μSv, 0.204 μSv, and 0.191 μSv. As a result of performing the corresponding sample t test of the average value according to the use of movable barrier walls, p <0.001 was found. As a result of the actual measurement, the medical exposure of the examiner due to the shielding wall in the laboratory decreased to 82.3%. In order to reduce occupational exposure in screening radiological laboratories, it is recommended that sufficient separation from radiation sources and the use of shielding walls are recommended.

• Journal of the Korean Magnetics Society
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• v.24 no.4
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• pp.101-106
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• 2014

The glass/Ta(5.8 nm)/NiFe(5 nm)/Cu(2.3 nm)/NiFe(3 nm)/IrMn(12 nm)/Ta(5.8 nm) GMR-SV (giantmagneto-resistance-spin valve) multilayer structure films with a magnetoresistance ratio (MR) of 5.0 % and a magnetic sensitivity (MS) of 1.5%/Oe was deposited by dc magnetron sputtering method. Also, GMR-SV device having a width of $7{\mu}m{\sim}8{\mu}m$ similar to the diameter of RBC (red blood cell) was fabricated by the light lithography process. When RBCs coupled with several magnetic beads with a diameter of $1{\mu}m$ dropped upon the GMR-SV device having MR = 1.06% and MS = 0.3 %/Oe, there is observed the variation of about included of a resistance value of ${\Delta}R=0.4{\Omega}$ and ${\Delta}MR=0.15%$ around a external magnetic field of -0.6 Oe. From these results, the GMR-SV device having the width magnitude of a few micron size can be applied as the biosensor for the analysis of a new magnetic property of hemoglobin inside of RBC combined to magnetic beads.

• The Korean Journal of Zoology
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• v.31 no.1
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• pp.49-55
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• 1988

A few SV4O-transformed human cells such as SV8O are potentially tumorigenic but rejected by athymic hosts. However, one cell line in this group (W118IVA-2) is known to be fully tumorigenic. Two clones were obtained after the injection of W118IVA-2, of which NW1SC1-1 was tumorigenic but NW18C1-2 was not in nude mice. As examined by Southern blot analysis, NW18C1-1 appears to contain more copy number of SV40 sequences than NW18C1-2 does. However, it was unable to demonstrate that this difference elicits the tumorigenicity in NW18C1-1 but not in NW18C1-2. Therefore, the latter clone was tested if it expresses SV40 early genes to produce large T as well as small t antigens using indirect immunofluorescent assay and immunoprecipitation. In addition, mouse NIH3T3 cells were transfected with the cellular DNA of NW1SC1-2 as well as that of NW18C1-1 to examine if the viral genomes in the clones can make the nontransformed cells to acquire malignant growth potential in vivo. The transformed cells expressed large T antigen and became tumorigenic. Thus, the transforming functions of NW1SC1-2 cell appers to be intact. These results clearly suggest that the inability of NW18C1-2 cell to form tumor in nude mice is not because they are inherently nontumorigenic. However, the possibility that the interaction of SV40 with its host differs in these clones can not he ruled out.

• Journal of Radiation Protection and Research
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• v.30 no.4
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• pp.185-196
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• 2005

Although medical exposure from diagnostic radiology procedures such as conventional x-rays, CT and PET scans is necessary for healthcare purposes, understanding its characteristics and size of the resulting radiation dose to patients is much of worth because medical radiation constitutes the largest artificial source of exposure and the medical exposure is in a trend of fast increasing particularly in the developed society. Annual collective doses and per-caput effective doses from different radiology procedures in Korea were estimated by combining the effective dose estimates per single medical procedure and the health insurance statistics in 2002. Values of the effective dose per single procedure were compiled from different sources including NRPB reports, ICRP 80, MIRDOSE3.1 code and independent computations of the authors. The annual collective dose reaches 27440 man-Sv (diagnostic radiology: 22880 man-Sv, nuclear medicine: 4560 man-Sv) which is reduced to the annual per-caput effective dose of 0.58 mSv by dividing by the national population of 47.7 millions. The collective dose is far larger than that of occupational exposures, in the country operated 16 nuclear power plants in 2002, which is no more than 70 man-Sv in the same year. It is particularly noted that the collective dose due to CT scans amounts 9960 man-Sv. These results implies that the national policy for radiation protection should pay much more attention to optimization of patient doses in medicine.

• Journal of radiological science and technology
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• v.42 no.3
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• pp.209-215
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• 2019

Comparison of the effective dose of the chest and the equivalent dose of the lens site in the radiation workers working at four medical institutions with the PET / CT room located in one metropolitan city and province from April 1 to June 30, 2018 Respectively. Radioactive medicine were measured at the time of dispensing and at the time of injection. In this experiment, the average dispensing time per patient was 5.7 minutes and the average injection time was 3.1 minutes. The equivalent dose at the lens site was $0.78{\mu}Sv/h$ for 1 mCi, and the effective dose for chest was $0.18{\mu}Sv/h$ per 1 mCi. The equivalent dose at the lens site during injection was $0.88{\mu}Sv/h$ per mCi and the effective dose of chest was $0.20{\mu}Sv/h$ per mCi. The daily effective dose of the chest was $0.9{\pm}0.6{\mu}Sv$ and the equivalent dose of the lens site was $3.6{\pm}1.4{\mu}Sv$ during daily dosing for 20 days. The effective dose of the chest during the day was $0.6{\pm}0.5{\mu}Sv$ and the equivalent dose of the lens was $2.2{\pm}1.0{\mu}Sv$. At the time of dispensing, the equivalent dose of the lens was $0.187{\pm}0.035mSv$, the effective dose of the chest was $0.137{\pm}0.055mSv$, the equivalent dose of the lens was $0.247{\pm}0.057mSv$, and the effective dose of the monthly chest was $0.187{\pm}0.021mSv$. As a result of the corresponding sample test, the equivalent dose and the effective dose of the chest, the effective dose of the chest, the effective dose of the chest, the effective dose of the chest, The equivalent dose of the lens and the effective dose of the chest were statistically significant (p<0.05) with a significance of 0.000. However, there was no statistically significant difference (p>0.05) between the equivalent dose and the effective dose of the chest, the equivalent dose of the lens at the time of injection, and the effective dose of the chest at 0.138 and 0.230, respectively.

• Journal of the Korean Society of Radiology
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• v.16 no.3
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• pp.357-363
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• 2022

This study aims to improve the safety inspection awareness of occupational exposure and help radiation safety management by analyzing radiation exposure doses by occupational type of radiation related-workers and radiation workers. Radiation-related workers and radiation workers were classified into three occupations (radiological technologist, doctors, and nurses). A nominal risk coefficient based on ICRP 103 was used to calculate the probability of causing side effects of the lungs due to exposure doses. As a result of analyzing the exposure dose of all workers for one year, the exposure dose of radiological technologist among radiation-related workers was 1.63 ± 2.84 mSv, doctors 0.12 ± 0.22 mSv, and nurses 0.59 ± 1.08 mSv. The one-year deep dose for radiation workers was 2.44 ± 3.30 mSv for radiological technologists, 0.19 ± 0.26 mSv for doctors, and 0.12 ± 0.00 mSv for nurses. Due to this dose, the probability of causing side effects in the lungs was 1.2 per 100,000 radiological technologist, 0.096 doctors, and 0.06 nurses. In this study, it is believed that the probability of side effects on lungs by occupation of radiation exposure dose will be studied and used as useful data for radiation safety management in relation to probabilistic effects in the future.

• Radiation Oncology Journal
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• v.18 no.2
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• pp.157-166
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• 2000

Purpose : This investigation was peformed in order to improve the health care of radiation workers, to predict a risk, to minimize the radiation exposure hazard to them and for them to realize radiation exposure danger when they work in radiation area in hospital. Methods and Materials : The documentations checked regularly for personal radiation exposure in four university hospitals in Pusan city in Korea between January 1, 1993 and December 31, 1997 were analyzed. There were 458 persons in this documented but 111 persons who worked less then one year were excluded and only 347 persons were included in this study. Results : The average of yearly radiation exposure of 347 persons was 1.52$\pm$1.35 mSv. Though it was less than 50mSv, the limitaion of radiation in law but 125 (36%) people received higher radiation exposure than non-radiation workers. Radiation workers under 30 year old have received radiation exposure of mean 1.87$\pm$1.01 mSv/year, mean 1.22$\pm$0.69 mSv between 31 and 40 year old and mean 0.97$\pm$0.43 mSv/year over 41year old (p<0.001). Men received mean 1.67$\pm$1.54 mSv/year were higher than women who received mean 1.13$\pm$0.61 mSv/year (p<0.01). Radiation exposure in the department of nuclear modicine department in spite of low energy sources is higher than other departments that use radiations in hospital (p<0.05). And the workers who received mean 3.59$\pm$1.81 msv/year in parts of management of radiation sources and injection of sources to patient receive high radiation exposure in nuclear medicine department (p<0.01). In department of diagnostic radiology high radiation exposure is in barium enema rooms where workers received mean 3.74$\pm$1.74 mSv/year and other parts where they all use fluoroscopy such as angiography room of mean 1.17$\pm$0.35 mSv/year and upper gastrointestinal room of mean 1.74$\pm$1.34 mSv/year represented higher radiation exposure than average radiation exposure in diagnostic radiology (p<0.01). Doctors and radiation technologists received higher radiation exposure of each mean 1.75$\pm$1.17 mSv/year and mean 1.50$\pm$1.39 mSv/year than other people who work in radiation area in hospital (p<0.05). Especially young doctors and technologists have the high opportunity to receive higher radiation exposure. Conclusions : The training and education of radiation workers for radiation exposure risks are important and it is necessary to rotate worker in short period in high risk area. The hospital management has to concern health of radiation workers more and to put an effort to reduce radiation exposure as low as possible in radiation areas in hospital.

• Proceedings of the KIEE Conference
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• 1997.07f
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• pp.2143-2145
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• 1997

SV_PWM inverter for Induction motor drive system was designed at SIMULINK environment in MATLAB. This paper was performed the analysis of output current harmonics using DSP blockset. It was roved in this paper that SV_PWM method has been ore effective than triangle comparison PWM method on harmonic reduction at steady state.

• Journal of the Korean Society of Marine Environment & Safety
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• v.16 no.2
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• pp.141-151
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• 2010

Harmful algal blooms (HABs), commonly known as red tides, are aquatic phenomena caused by the rapid growth and accumulation of certain microalgae, which can lead to marked discoloration of surface waters, and severe impacts on public health, commerce, and the environment. In South Korea, the red tides have been a serious and recurrent problem, especially along the south coast. Plenty of yellow loess was used to control an outbreak of the red tides for 15 years from 1996 until now. Yellow loess was almost sprayed in the vicinity of a large fish farming industry. In this research, the distribution characteristics and density distribution of zooplankton were investigated in autumn (Oct. 2008) and spring (Apr. 2009) using volume backscattering strength (SV) calculated by the zooplankton collected with north pacific standard (NORPAC) net and the echo intensity measured with ADCP at stations on the study area in the spraying ocean of yellow loess (SOYL), and the non-spraying ocean of yellow ocean (NOYL) by the red tide generating every year. The species number and the individuals per unit volume of the zooplankton collected in NOYL was high and it which was collected in SOYL was low. As a result of comparing the volume backscattering strength ($SV_c$) calculated by species and length of the zooplankton collected with NORPAC net with the volume backscattering strength ($SV_m$) calculated by the echo intensity measured with ADCP at stations on the study area, although $SV_c$ and $SV_m$ of NOYL were generally in agreement, $SV_m$ of SOYL was higher than $SV_c$ 4.3dB, i.e. ADCP is greatly influenced by suspended solid in SOYL. The horizontal distribution map of $SV_m$ at the study area in autumn (Oct. 2008) and spring (Apr. 2009) was drawn. $SV_m$ of SOYL is higher than NOYL and autumn is higher than spring. $SV_m$ can suppress the overestimate or underestimate of $SV_c$.