• The Korean Journal of Nuclear Medicine Technology
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• v.23 no.1
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• pp.75-79
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• 2019

Purpose Cadmium-zinc-telluride (CZT) camera with semiconductor detector is capable of dynamic myocardial perfusion SPECT for coronary flow reserve (CFR). Image acquisition with the heart positioned within 2 cm in the center of the quality field of view (QFOV) is recommended because the CZT detector based on focused multi-pinhole collimators and is stationary gantry without rotation. The aim of this study was to investigate the optimal method for measuring position of the heart within the center of the QFOV when performing dynamic myocardial perfusion SPECT with the Discovery NM 530c camera. Materials and Methods From June to September 2018, 45 patients were subject to dynamic myocardial perfusion SPECT with D530c. For accurate heart positioning, the patient's heart was scanned with a mobile ultrasound and marked at the top of the probe where the mitral valve (MV) was visible in the parasternal long-axis view (PLAX). And, the marked point on the patient's body matched with the reference point indicated CZT detector in dynamic stress. The heart was positioned to be in the center of the QFOV in rest. The coordinates of dynamic stress and rest were compared statistically. Results The coordinates of the dynamic stress using mobile ultrasound and those taken of the rest were recorded for comparative analysis with regard to the position of the couch and analyzed. There were no statistically significant differences in the coordinates of Table in & out, Table up & down, and Detector in & out (P > 0.05). The difference in distance between the 2 groups was measured at $0.25{\pm}1.00$, $0.24{\pm}0.96$ and $0.25{\pm}0.82cm$ respectively, with no difference greater than 2 cm in all categories. Conclusion The position of the heart taken using mobile ultrasound did not differ significantly from that of the center of the QFOV. Therefore, The use of mobile ultrasound in dynamic stress will help to select the correct position of the heart, which will be effective in clinical diagnosis by minimizing the image quality improvement and the patient's exposure to radiation.

• The Korean Journal of Nuclear Medicine Technology
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• v.23 no.1
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• pp.45-49
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• 2019

Purpose Lung Ventilation Scan(LVS) images directly inhaled radiation gas to evaluate lung ventilation ability. Therefore, it is influenced by various factors related to inhalation, including number of breaths, respiratory duration, respiration rate, and breathing method. In actual LVS examinations, it is difficult for objectify the patient's ability to inhale, and there is currently no known index related to inhalation. Therefore, this study confirms the correlation between counts per second(cps) in LVS and the results of pulmonary function test(PFT) and evaluate its usefulness as an objective indicator of inhalation. Materials and Methods From October 2010 to September 2018, 36 Chronic Obstructive Pulmonary Disease(COPD) patients who had both LVS and PFT were classified by severity(Mild, Moderate, Severe). LVS was performed by creating Technegas with Vita Medical's Technegas Generator and inhaling it to the patient. LVS images were acquired with Philips's Forte equipment., and PFT used Carefusion's Vmax Encore 22. The correlation between the cps measured by setting the region of interest(ROI) of both lungs on the LVS and the forced vital capacity(FVC), forced expiratory volume in one second($FEV_1$), $FEV_1/FVC$ of the results of PFT was compared and analyzed. Results We analyzed the correlation between cps of LVS using Technegas and the results of PFT by classifying COPD patients according to severity. Correlation coefficient between $FEV_1/FVC$ and cps was Severe -0.773, Moderate -0.750, and Mild -0.437. The Severe and Modulate result values were statistically significant(P<0.05) and Mild was not significant(P=0.155). On the other hand, the correlation coefficient between FVC and cps was statistically significant only in Mild and it was 0.882(P<0.05). Conclusion According to the study, we were able to analyze correlation between cps of LVS using Technegas and the results of PFT in COPD Patients. Using this result, when performing a LVS, the results of PFT can be used as an index of inhaling capacity. In addition, it is thought that it will be more effective for the operation of the exam rooms.

• Korean Journal of Heritage: History & Science
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• v.48 no.1
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• pp.4-23
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• 2015

In the Buddhist paintings of the four devas, there is a change in the paper material of V aisravana(多聞天) in the early Joseon Dynasty. Until Goryeo Dynasty, Damuncheonwang, who holds a tower(塔) on the right side of Buddha was changed to the form which holds a mandolin(琵琶) in the early Joseon Dynasty. This change was first checked in Byeonsangdo in the Yuan period "The Avatamska Sutra(大方廣佛華嚴經, 1330~1336)", however the actual paper material change in the Buddhist painting is found first as a mural at the Tibetan temples, Cheolbangsa(哲蚌寺), Odunsa(吳屯寺), Baekgeosa(白居寺), which showed the change of tower which Vaisravaṇa held into mongoose. In Joseon Dynasty, also, new distribution of the four devas appeared first, which showed the change of paper material in the first floor roof-stones of Wongaksaji sipcheung seoktap, . However, the position of the four devas which held a tower and a mandolin consistently appear in the Buddhist paintings in the early Joseon Dynasty by mixing on the left and the right. This means the possibility that the paper material and the position of the four devas might be flexible in the early Joseon Dynasty. Just like reflecting this, painting image of the four devas in illustration of "saddharma-pundari-ka-$s{\bar{u}}tra$(Ming 1432, National Museum of Korea)" and illustration of "Jebulsejonyeorae-bosaljonjamyeongching-gagok(제불세존여래 보살존자명칭가곡, 1417)" has opposite position from each other. Therefore, the phenomenon in the Buddhist paintings of the early Joseon had a transitional characteristic which did not secure the fixed form of painting image by illustration of two copies where paper materials of the four devas were different, which characteristic can be said to be the characteristic of art in the transitional period.

• Economic and Environmental Geology
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• v.52 no.3
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• pp.251-258
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• 2019

During the detailed geological survey around the southern Yangsan Fault, we newly found a Quaternary fault outcrop, which cuts unconsolidated sediments. The fault named the Sinwoo site, located in the Sinwoo pasture, Miho-ri, Duseo-myeon, Ulsan metropolitan city, is the first discovered Quaternary fault near the western part of the south Yangsan Fault. In this study, we provide information on characteristics of fault geometry and unconsolidated sediment at Sinwoo site based on the analysis data of topography, drainage, and lineament around the study site. The fault site is situated at pediment slope, but fan-shaped middle terrace, as well as thick sediment exposed at low terrace, indicates that the unconsolidated sediments have been deposited in the alluvial fan environment. The drainage develops to the third-order drainage system, and the first and the second drainage system meet at right angles to each other and form a radial drainage pattern. In addition, the NE-SW direction lineaments can be identified on the basis of the curvature of the river and the step of the topographic relief, running over the Sinwoo site. The fault of $N30-35^{\circ}E/79-82^{\circ}SE$ shows ~ 5.8 m apparent vertical offset and dominantly reverse-slip sense based on slickenline, rotation of pebbles, and drag folding at footwall. However, some discontinuous sediments observed in the footwall are interpreted as fissure-filling materials due to the strike-slip movement. Now, we are under multidisciplinary investigations of additional field survey and age dating in order to determine the evolution of Sinwoo site fault during the Quaternary.

• The Korean Journal of Nuclear Medicine Technology
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• v.22 no.2
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• pp.92-96
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• 2018

Purpose In case of nuclear medical hepatobiliary scan, To quantitatively evaluate contractility of a gallbladder, gallbladder ejection fraction (GBEF%) is calculated from anterior images using fatty meal. However, when a gallbladder and other organs overlap on an anterior image, the gallbladder ejection fraction is not accurately evaluated. In order to reduce this error, the objective of our study was to figure out whether there is a significant difference in GBEF% calculated from the anterior and right lateral images. Materials and Methods After intravenous injection of 99mTc-Mebrofenin 370 MBq to randomly 50 patients who visited our hospital, we started to examine nuclear hepatobiliary scan. Using skylight(Philips, United States), we acquired anterior and right lateral image at 10 minutes, 20 minutes, 30 minutes, 60 minutes, 90minutes after injection. Using images at 60 and 90 minutes, gallbladder ejection fraction (GBEF%) was calculated from the anterior and right lateral images using JETstream workspace. For drawing more accurate ROI, CT images were referenced and 4 radiologists calculated the GBEF% in the same image and calculated the average value. We assessed whether there was a significant difference in GBEF% calculated from the anterior and right lateral images using SPSS program(Statistical Package for the Social Science, SPSS Ver.18 Inc. USA). Results About randomly 50 patients, the average value of the GBEF% calculated from the anterior image was 63.212 and the average value of the GBEF% calculated from the right lateral image was 62.666. GBEF% decreased 0.433% on the right lateral image compared with anterior image. Result of paired sample t-test, p value is over 0.05. So, there was no significant difference in GBEF% calculated from the anterior and right lateral images. Conclusion In the case that a gallbladder and other organs are not separated on an anteior image, Right lateral image would be better to acquire more accurate GBEF% than using anterior image.

• The Korean Journal of Nuclear Medicine Technology
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• v.22 no.2
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• pp.97-100
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• 2018

Purpose The glomerular filtration rate (GFR) test is an important indicator of glomerular filtration and has been used to test renal function and the extent of its function. The GFR test is performed by intravenous injection of radioactive medicines made of $^{51}Cr$-EDTA, and blood concentration is measured by taking blood according to the elapsed time. also, PET-CT, bone scan, transfusion and so on will affect the outcome. Therefore, we will improve the quality of the test by providing guidelines for the GFR test for more accurate testing. Materials and Methods 5 mL of physiological saline solution and 2 mL of $^{51}Cr$-EDTA solution are used to make 5 mL of the radiopharmaceutical solution to be injected into the patient. First, the syringe weight is measured before the injection, and then the radioactive medicine is injected into the patient's vein and the syringe weight is measured after the injection. Blood sampling is performed twice in total. In adults, blood is collected 3 hours / 5 hours after injection and in children 2 hours / 5 hours after injection. The blood sample is centrifuged at 3300 rpm for 5 minutes. Standard solution is prepared by filling diluent water up to the scale indicated in the 200-mL volumetric flask, discarding $500{\mu}L$, injecting $500{\mu}L$ of GFR reagent and mixing well. $500{\mu}L$ each of the standard solution is dispensed into two test tubes, and $500{\mu}L$ of each of the plasma samples collected in time is dispensed into two test tubes and measured with a Cobra Counter. Results At present, the reference range applied in this study is $119.5{\pm}30.3ml/min/1.73m2$ for males and $125.2{\pm}28.2ml/min/1.73m^2$ for females. Conclusion The GFR test is conducted using radioactive medical products. GFR testing is performed as a scheduled test, but PET-CT, dialysis and transfusion, which may affect GFR testing, may be scheduled during GFR testing. Therefore, we could get accurate GFR test results by notifying the ward and department beforehand when booking.

• Korean Journal of Remote Sensing
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• v.37 no.3
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• pp.515-530
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• 2021

This study is to estimate soil moisture (SM) using Sentinel-1A/B C-band SAR (synthetic aperture radar) images and Multiple Linear Regression Model(MLRM) in the Yongdam-Dam watershed of South Korea. Both the Sentinel-1A and -1B images (6 days interval and 10 m resolution) were collected for 5 years from 2015 to 2019. The geometric, radiometric, and noise corrections were performed using the SNAP (SentiNel Application Platform) software and converted to backscattering coefficient of VV and VH polarization. The in-situ SM data measured at 6 locations using TDR were used to validate the estimated SM results. The 5 days antecedent precipitation data were also collected to overcome the estimation difficulty for the vegetated area not reaching the ground. The MLRM modeling was performed using yearly data and seasonal data set, and correlation analysis was performed according to the number of the independent variable. The estimated SM was verified with observed SM using the coefficient of determination (R²) and the root mean square error (RMSE). As a result of SM modeling using only BSC in the grass area, R² was 0.13 and RMSE was 4.83%. When 5 days of antecedent precipitation data was used, R² was 0.37 and RMSE was 4.11%. With the use of dry days and seasonal regression equation to reflect the decrease pattern and seasonal variability of SM, the correlation increased significantly with R² of 0.69 and RMSE of 2.88%.

• The Korean Journal of Nuclear Medicine Technology
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• v.25 no.1
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• pp.29-33
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• 2021

Purpose Plasma renin activity (PRA) test is important for the diagnosis of primary aldosteronism. PRA is an easily deformed substance in vitro and affected by temperature changes. Laboratory of ASAN medical center has consistently found that there was a difference between the initial and re-experimental results. We compared and analyzed the differences in PRA test results according to the sample storage status. Materials and Methods The measurement of PRA was performed by using the radioimmunoassay. From August to September 2020, 43 PRA re-test samples were tested with different sample storage condition. The first group was re-examined by freezing the plasma-separated samples at -18℃, and the second group was re-examined with refrigerated EDTA sample. Also, additional tests were conducted on 13 PRA samples to verify the effect on thawing temperature differences in plasma-separated samples. The same samples were divided into two parts and stored frozen at -18℃, respectively, and thawing samples in room temperature and those in refrigerator were were conducted. Each result was compared and analyzed based on the initial experimental results. Results The results of re-examination after frozen storing plasma separation samples showed a lower correlation than the results of re-examination with EDTA plasma samples in refrigerator. When calculating the percentage based on the initial test results, the average percentage of each was 404.9% and 133.8%. The correlation coefficient was also R=0.8501 and R=0.9966, respectively, showing a higher correlation between plasma in the refrigerated sample EDTA tube. In comparison experiments with differences in thawing temperature, average percentage of the results of initial test and room temperature thawing was 94.3% and the average percentage of the results of refrigerated thawing was 88.0%. After again freezing the sample, the average percentage of the second room temperature thawing result is 107.5%, and the second refrigerated thawing group is 112.7%. Both groups showed an increase from first thawing. Conclusion A comparative analysis of retesting according to differences in sample storage methods in PRA tests showed a higher correlation between the results of retesting of the refrigerated EDTA plasma. And repeated freezing and melting of plasma separation samples, regardless of temperature during defrosting, has been shown to affect results. Therefore, retest of PRA should re-collect plasma from original EDTA plasma to increase reproducibility.

• Economic and Environmental Geology
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• v.54 no.4
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• pp.441-456
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• 2021

The Cretaceous Duwon Formation was studied on the basis of sedimentologic analysis in order to unravel geologic conditions for the development of the streamflow-dominated alluvial fan under arid to semi-arid climatic conditions. The Duwon Formation unconformably overlies the Paleoproterozoic gneiss (basement). Based on the sedimentologic analysis, the Duwon Formation is interpreted to have been deposited in gravelly braided stream (FA-1) near the basement, laterally transitional to sandy braided stream (FA-2) and floodplain environments (FA-3) with distance (< 7 km) from the basement. Lateral changes in sedimentary facies and the well development of calcrete nodules in FA-3, together with radial paleocurrent directions measured in FA-1, are suggestive of the deposition of the Duwon Formation in streamflow-dominated alluvial fan under arid to semi-arid climatic conditions. Recent analysis of detrital zircon chronology suggests that sediments of the Duwon Formation were derived from the southwestern part of the Korean peninsula, including the western part of Yeongnam Massif and the southwestern part of Okcheon Belt. This implies the alluvial fan where the Duwon Formation accumulated had the large drainage basin. Because the large drainage basin can supply the significant amounts of water and temporarily store the sediments within the basin, watery floodwater carried sediments to the alluvial fan rather than the debris flows. Furthermore, the drainage basin largely composed of coarse-grained metamorphic and igneous rocks produced sand-grade sediments, preventing evolution of floodwater into debris flows. We suggest that combined effects of the large drainage basin and its coarse-grained metamorphic and igneous rocks provided favorable conditions for the development of streamflow-dominated alluvial fan, despite arid to semi-arid climatic conditions during sedimentation.

• The Korean Journal of Nuclear Medicine Technology
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• v.25 no.1
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• pp.15-20
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• 2021

Purpose This article studies the relationship between the length of a kidney measured by two scanning methods: Kidney Computed Tomography (CT) and ^99mTc-Dimercaptosuccinic acid (DMSA) renal scan. Kidney CT provides a better anatomic assessment, while ^99mTc-DMSA renal scan is superior in the kidney function test. Materials and Methods From January to December of 2019, two hundred patients who had Kidney CT and Tc^99m-DMSA renal scan were chosen for this study. SPSS17.0 was selected for statistical analysis. Results Due to the effect of the breathing and resolution of ^99mTc-DMSA renal scan, it showed the kidney's relatively longer length than the length of Kidney CT. For the same kidney, the length comparison among different brands' Gamma cameras was negligible. The length difference within the same age group did not show a noticeable discrepancy. However, there was a length difference between the radio technologists. Kidney CT and ^99mTc-DMSA renal scan indicated a strong positive correlation between the length of the left and right kidney. Conclusion It is necessary to establish a standardized measurement method for measuring kidney length using ^99mTc-DMSA renal scan. The kidney's functional changes and length changes are indications of Kidney diseases. Especially, pediatric patients tend to use ^99mTc-DMSA renal scan for assessing the kidney's shape and the function to avoid potential radiation exposure during the Kidney CT. Therefore, it is significant to provide not only the kidney's functional information but also an anatomic analysis, including the kidney's size, length, and location through the ^99mTc-DMSA renal scan.