• Journal of Radiation Industry
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• v.11 no.3
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• pp.151-155
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• 2017

MDCT is used to determine how the noise changes as the slice thickness changes. Noise according to thickness of 1.5, 3.0, 5.0 and 10.0 mm was analyzed using the Siemens (Somatom Definition Flash, Germany) equipment and calibration conditions such as tube voltage and tube current using the calibration QC phantom. 1.5, 3.0, 5.0 and 10.0 mm, respectively. The mean HU was 1.5 mm (7.7 HU), 3.0 mm (4.9 HU) and was reduced by 59.5% from 1.5 mm. 5.0 mm (3.9 HU) and 97.6% compared to 1.5 mm, 10.0 mm (3.1 HU) and 148% less than 1.5 mm. It was found that as slice thickness increased, noise decreased, while slice thickness decreased. In conclusion, setting the appropriate slice thickness for each site may be useful for obtaining appropriate noise and image quality.

• Journal of radiological science and technology
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• v.47 no.3
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• pp.175-182
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• 2024

Advanced modeled iterative reconstruction (ADMIRE) represents a repetitive reconstruction method that can adjust strength and kernel, each of which are known to affect computed tomography (CT) image quality. The aim of this study was to quantitatively analyze the noise and spatial resolution of CT images according to ADMIRE control factors. Patient images were obtained by applying ADMIRE strength 2 and 3, and kernel B40 and B59. For quantitative evaluations, the noise level, spatial resolution, and overall image quality were measured using coefficient of variation (COV), edge rise distance (ERD), and natural image quality evaluation (NIQE). The superior values for the average COV, ERD, and NIQE results were obtained for the ADMIRE reconstruction conditions of ADMIRE 2 + B40, ADMIRE 3 + B59, and ADMIRE3 + B59. NIQE, which represents the overall image quality based on no-reference, was about 6.04 when using ADMIRE 3 + B59, showing the best result among the reconstructed image acquisition conditions. The results of this study indicate that the ADMIRE strength and kernel chosen for use in ADMIRE reconstruction have a significant impact on CT image quality. This highlights the importance of adjusting to the control factors in consideration of the clinical environment.

• Journal of radiological science and technology
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• v.30 no.4
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• pp.427-433
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• 2007

This study was conducted to investigate the usefulness of PASL image technique through visual and quantitative assessment by dividing CBF image, conventional perfusion magnetic resonance image, anterior cerebral artery, middle cerebral artery and posterior cerebral artery into 6 territories both right and left in moyamoya disease. In visual assessment, the scope of decreased perfusion in the PASL CBF image and conventional perfusion MR CBF image agreed with the position of deficiency in the MR image. The quantitative assessment, showed that the scope and position of decreased perfusion accord with both in the PASL CBF image and the existing conventional perfusion MR CBF image but the assessment of measuring the quantity of perfusion according to signal intensity showed a little difference.

• Journal of the Korean Society of Radiology
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• v.8 no.7
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• pp.389-395
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• 2014

The research was carried out to develop a animal model of malignant brain tumor for the researches in glioblastoma multiform (GBM) diagnosis and therapy. C6 cells were transplanted into the right striatum of SD rat using stereotactic instrument for the development. The developed animal model was verified by MRI and H&E stain assay of anatomicohistological examination. The MRI observations showed that the tumor developed at the injection site at the 7 days after glioblastoma inoculation. At 14 days post inoculation, the tumor grew to a large volume occupying almost a half of the right cerebral hemisphere. It was confirmed that the expression of excessive mitosis and pleomorphism in anatomicohistological examination. The developed animal model must be necessary and useful tool for the in vivo level research in the development of the new modality for the diagnosis and therapy of brain cancer.

• Journal of the Korean Society of Radiology
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• v.9 no.2
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• pp.121-124
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• 2015

Digital Mammography is very important for the early diagnosis of breast cancer. but excessive radiation dose to the patient may increase the probability of occurrence of breast cancer. absorbed dose rate and signal, noise, and contrast in accordance with the change of the filter, and analyzed the signal-to-noise ratio. absorbed dose rate GE Equipment is higher than that of Siemens and Hologic. using the material of Mo / Mo was lower than the other target-filter combination. SNR of Siemens equipment is high and measured high when Mo / Mo selected, the other two devices was measured high when Mo / Rh selected. when you choose a target-filter combination our results will be a good indicator.

• Proceedings of the IEEK Conference
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• 2007.07a
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• pp.279-280
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• 2007

Airway wall thickness is an important bio-marker for evaluation of pulmonary diseases such as stenosis, bronchiectasis. Nevertheless, an image-based analysis of the airway tree can provide precise and valuable airway size information, quantitative measurement of airway wall thickness in CT images involves various sources of error and uncertainty. So we have developed an accurate airway wall measurement technique for small airways with three-dimensional (3-D) approach. To illustrate performance of these techniques, we used airway phantom that consisted of 4 acryl tubes with various inner and outer diameters. Results show that evaluation of interpolation and deconvolution methods of airways in 3-D CT images, and significant improvement over the full-width-half-maximum method for measurement of not only location of the luminal and outer edge of the airway wall but airway wall thickness.

• Journal of radiological science and technology
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• v.39 no.1
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• pp.59-69
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• 2016

The objective of this study was to analyze the factors influencing integrated bolus peak timing in contrast-enhanced computed tomographic angiography (CTA) and to determine a method of calculating personal peak time. The optimal time was calculated by performing multiple linear regression analysis, after finding the influence factors through correlation analysis between integrated peak time of contrast medium and personal measured value by monitoring CTA scans. The radiation exposure dose in CTA was $716.53mGy{\cdot}cm$ and the radiation exposure dose in monitoring scan was 15.52 mGy (2 - 34 mGy). The results were statistically significant (p < .01). Regression analysis revealed, a -0.160 times decrease with a one-step increase in heart rate in male, and -0.004, -0.174, and 0.006 times decrease with one-step in DBP, heart rate, and blood sugar, respectively, in female. In a consistency test of peak time by calculating measured peak time and peak time by using the regression equation, the consistency was determined to be very high for male and female. This study could prevent unnecessary dose exposure by encouraging in clinic calculation of personal integrated peak time of contrast medium prior to examination.

• Journal of the Korean Society of Radiology
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• v.11 no.5
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• pp.371-377
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• 2017

General phantom for practical X-ray photography Practical phantom is an indispensable textbook for radiology, but it is difficult for existing commercially available phantom to be equipped with various kinds of phantom because it is an expensive import. Using 3D printing technology, I would like to make the general phantom for practical X-ray photography less expensive and easier. We would like to use a skeleton model that was produced based on CT image data using a 3D printer of FDM (Fused Deposition Modeling) method as a phantom for general X-ray imaging. 3D slicer 4.7.0 program is used to convert CT DICOM image data into STL file, convert it to G-code conversion process, output it to 3D printer, and create skeleton model. The phantom of the completed phantom was photographed by X - ray and CT, and compared with actual medical images and phantoms on the market, there was a detailed difference between actual medical images and bone density, but it could be utilized as a practical phantom. 3D phonemes that can be used for general X-ray practice can be manufactured at low cost by utilizing 3D printers which are low cost and distributed and free 3D slicer program for research. According to the future diversification and research of 3D printing technology, it will be possible to apply to various fields such as health education and medical service.

• Journal of the Korean Society of Radiology
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• v.15 no.2
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• pp.117-123
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• 2021

This paper is to establish a basis for a dose reduction strategy by confirming correlations with the factors that may affect the radiation dose based on the dose records in low-dose chest CT and abdominal non-contrast CT. In order to find out the causes of unnecessary exposure, the correlation between seven factors (age, gender, height, weight, BMI, patient status [inpatient and outpatient], and use of dose modulation) and CT dose were identified. Logistic regression was used as the statistical analysis for correlation verification. In the low dose chest CT, as the higher values of height and BMI and dose modulation off were associated with lowering the risk exceeding Diagnostic Reference Levels(DRL) (odds ration<1, p<0.05). However, as woman compared to man and the higher values of weight were associated with highering the risk exceeding DRL (odds ration>1, p<0.05). In the abdomen CT, as dose modulation off were associated with lowering the risk exceeding DRL (odds ration<1, p<0.05). Therefore It is necessary to conduct research on the relationship between various factors affecting radiation exposure and patient radiation dose for reducing the dose.

• Journal of the Korean Society of Radiology
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• v.15 no.2
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• pp.139-145
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• 2021

This study is to confirm the range of tube voltage for Chest X-ray in DR system by comparing with dose area product (DAP) and effective dose in efficient detector exposure index (DEI) range. GE definium 8000 was used to for the phantom study. The range of tube voltage is 60~130 kVp and of mAs is 2.5~40 mAs. The acquired images were classified into efficient DEI groups, then calculated effective dose with DAP by using a PC-Based Monte Carlo Program 2.0. The signal to noise ratio (SNR) was measured at 4 regions, including the thoracic spine, the lung area with the ribs, the lung area without the ribs, and the liver by using Picture Archiving and Communication System. The significance of the group for each tube voltage was verified by performing the kruskal-wallis test and the mann-whitney test as a post-test. When set to 4 groups dependned on the tube voltage, DAP showed significant differences; 60 kVp and 80 kVp, and 60 kVp and 90 kVp (p= 0.034, 0.021). Effective dose exhibited no statistically significant differences from the all of the group (p>0.05). SNR exhibited statistically significant differences from the all of the group in the liver except compared to 80 kVp and 90 kVp (p<0.05). Therefore, high tube voltages of 100 kVp or more need to be reconsidered in terms of patient dose and imaging in order to represent an appropriate chest X-ray image in a digital system.