• Proceedings of the Korean Institute of Building Construction Conference
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• 2021.05a
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• pp.211-212
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• 2021

This study was conducted to derive quantitative air void volume calculation techniques in various complexes with porosity. Calculation of voids in a complex is an essential factor in improving mechanical properties, and quantitative measurement techniques are needed because the environment is not constant to apply the currently used ASTM criteria. Using the analysis technique obtained through 2D image analysis, it is believed that meaningful results can be derived through Micro CT analysis results and cross-check later.

• The Korean Journal of Nuclear Medicine Technology
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• v.18 no.1
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• pp.127-133
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• 2014

Purpose: Low dose of PET/CT is important because of Patient's X-ray exposure. The aim of this study was to evaluate the effectiveness of low-dose PET/ CT image through the CTAC and QAC of patient study and phantom study. Materials and Methods: We used the discovery 710 PET/CT (GE). We used the NEMA IEC body phantom for evaluating the PET data corrected by ultra-low dose CT attenuation correction method and NU2-94 phantom for uniformity. After injection of 70.78 MBq and 22.2 MBq of 18 F-FDG were done to each of phantom, PET/CT scans were obtained. PET data were reconstructed by using of CTAC of which dose was for the diagnosis CT and Q. AC of which was only for attenuation correction. Quantitative analysis was performed by use of horizontal profile and vertical profile. Reference data which were corrected by CTAC were compared to PET data which was corrected by the ultra-low dose. The relative error was assessed. Patients with over weighted and normal weight also underwent a PET/CT scans according to low dose protocol and standard dose protocol. Relative error and signal to noise ratio of SUV were analyzed. Results: In the results of phantom test, phantom PET data were corrected by CTAC and Q.AC and they were compared each other. The relative error of Q.AC profile was been calculated, and it was shown in graph. In patient studies, PET data for overweight patient and normal weight patient were reconstructed by CTAC and Q.AC under routine dose and ultra-low dose. When routine dose was used, the relative error was small. When high dose was used, the result of overweight patient was effectively corrected by Q.AC. Conclusion: In phantom study, CTAC method with 80 kVp and 10 mA was resulted in bead hardening artifact. PET data corrected by ultra- low dose CTAC was not quantified, but those by the same dose were quantified properly. In patients' cases, PET data of over weighted patient could be quantified by Q.AC method. Its relative difference was not significant. Q.AC method was proper attenuation correction method when ultra-low dose was used. As a result, it is expected that Q.AC is a good method in order to reduce patient's exposure dose.

• The Korean Journal of Nuclear Medicine Technology
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• v.28 no.1
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• pp.41-47
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• 2024

Purpose: ¹⁸F-FET, a radiopharmaceutical based on a Tyrosine amino acid derivative using the Sodium-Potassium Pump-independent Transporter (System L) for non-invasive evaluation of primary, recurrent, and metastatic brain tumors, exhibits distinct characteristics. Unlike the widely absorbed ¹⁸F-FDG in both tumor and normal brain tissues, ¹⁸F-FET demonstrates specific uptake only in tumor tissue while almost negligible uptake in normal brain tissue. This study aims to compare and evaluate the usefulness of ¹⁸F-FDG and ¹⁸F-FET Brain PET/CT quantitative analysis in brain tumor diagnosis. Materials and Methods: In 46 patients diagnosed with brain gliomas (High Grade: 34, Low Grade: 12), Brain PET/CT scans were performed at 40 minutes after ¹⁸F-FDG injection and at 20 minutes (early) and 80 minutes (delay) after ¹⁸F-FET injection. SUV_max and SUV_peak of tumor areas corresponding to MRI images were measured in each scan, and the SUV_max-to-SUV_peak ratio, an indicator of tumor prognosis, was calculated. Differences in SUV_max, SUV_peak, and SUV_max-to-SUV_peak ratio between ¹⁸F-FDG and ¹⁸F-FET early/delay scans were statistically verified using SPSS (ver.28) package program. Results: SUV_max values were 3.72±1.36 for ¹⁸F-FDG, 4.59±1.55 for ¹⁸F-FET early, and 4.12±1.36 for ¹⁸F-FET delay scans. The highest SUV_max was observed in ¹⁸F-FET early scans, particularly in HG tumors (4.85±1.44), showing a slightly more significant difference (P<0.0001). SUV_peak values were 3.33±1.13 for ¹⁸F-FDG, 3.04±1.11 for ¹⁸F-FET early, and 2.80±0.96 for ¹⁸F-FET delay scans. The highest SUV_peak was in ¹⁸F-FDG scans, while the lowest was in ¹⁸F-FET delay scans, with a more significant difference in HG tumors (P<0.001). SUV_max-to-SUV_peak ratio values were 1.11±0.09 for ¹⁸F-FDG, 1.54±0.22 for ¹⁸F-FET early, and 1.48±0.17 for ¹⁸F-FET delay scans. This ratio was higher in ¹⁸F-FET scans for both HG and LG tumors (P<0.0001), but there was no statistically significant difference between ¹⁸F-FET early and delay scans. Conclusion: This study confirms the usefulness of early and delay scans in ¹⁸F-FET Brain PET/CT examinations, particularly demonstrating the changes in objective quantitative metrics such as SUV_max, SUV_peak, and introducing the SUV_max-to-SUV_peak ratio as a new evaluation metric based on the degree of tumor malignancy. This is expected to further contributions to the quantitative analysis of Brain PET/CT images.

• Journal of radiological science and technology
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• v.31 no.1
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• pp.71-81
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• 2008

Our objective was to evaluate the image of spatial domain filtering as an alternative to additional image reconstruction using different kernels in MDCT. Derived from thin collimated source images were generated using water phantom and abdomen B10(very smooth), B20(smooth), B30(medium smooth), B40 (medium), B50(medium sharp), B60(sharp), B70(very sharp) and B80(ultra sharp) kernels. MTF and spatial resolution measured with various convolution kernels. Quantitative CT attenuation coefficient and noise measurements provided comparable HU(Hounsfield) units in this respect. CT attenuation coefficient(mean HU) values in the water were values in the water were $1.1{\sim}1.8\;HU$, air($-998{\sim}-1000\;HU$) and noise in the water($5.4{\sim}44.8\;HU$), air($3.6{\sim}31.4\;HU$). In the abdominal fat a CT attenuation coefficient($-2.2{\sim}0.8\;HU$) and noise($10.1{\sim}82.4\;HU$) was measured. In the abdominal was CT attenuation coefficient($53.3{\sim}54.3\;HU$) and noise($10.4{\sim}70.7\;HU$) in the muscle and in the liver parenchyma of CT attenuation coefficient($60.4{\sim}62.2\;HU$) and noise ($7.6{\sim}63.8\;HU$) in the liver parenchyma. Image reconstructed with a convolution kernel led to an increase in noise, whereas the results for CT attenuation coefficient were comparable. Image scanned with a high convolution kernel(B80) led to an increase in noise, whereas the results for CT attenuation coefficient were comparable. Image medications of image sharpness and noise eliminate the need for reconstruction using different kernels in the future. Adjusting CT various kernels, which should be adjusted to take into account the kernels of the CT undergoing the examination, may control CT images increase the diagnostic accuracy.

• Journal of Periodontal and Implant Science
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• v.48 no.4
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• pp.202-212
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• 2018

Purpose: Bone-to-implant contact (BIC) is difficult to measure on micro-computed tomography (CT) because of artifacts that hinder accurate differentiation of the bone and implant. This study presents an advanced algorithm for measuring BIC in micro-CT acquisitions using a spiral scanning technique, with improved differentiation of bone and implant materials. Methods: Five sandblasted, large-grit, acid-etched implants were used. Three implants were subjected to surface analysis, and 2 were inserted into a New Zealand white rabbit, with each tibia receiving 1 implant. The rabbit was sacrificed after 28 days. The en bloc specimens were subjected to spiral (SkyScan 1275, Bruker) and round (SkyScan 1172, SkyScan 1275) micro-CT scanning to evaluate differences in the images resulting from the different scanning techniques. The partial volume effect (PVE) was optimized as much as possible. BIC was measured with both round and spiral scanning on the SkyScan 1275, and the results were compared. Results: Compared with the round micro-CT scanning, the spiral scanning showed much clearer images. In addition, the PVE was optimized, which allowed accurate BIC measurements to be made. Round scanning on the SkyScan 1275 resulted in higher BIC measurements than spiral scanning on the same machine; however, the higher measurements on round scanning were confirmed to be false, and were found to be the result of artifacts in the void, rather than bone. Conclusions: The results of this study indicate that spiral scanning can reduce metal artifacts, thereby allowing clear differentiation of bone and implant. Moreover, the PVE, which is a factor that inevitably hinders accurate BIC measurements, was optimized through an advanced algorithm.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.32 no.1
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• pp.49-56
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• 2010

Objective: To evaluate nasal and upper lip changes after Le Fort I surgery by means of images taken with a three-dimensional computed tomography (3D-CT). Methods: Fifteen patients (9 female and 6 male, mean age 21.9 years) with preoperative and postoperative 3D-CT were studied. The patients underwent maxillary movement with impaction or elongation, and advancement or setback. With the 3D-CT which presents reconstructive soft tissue images, preoperative and postoperative measurement and analysis were performed for nasal tip projection angle, columellar angle, supratip break angle, nasolabial angle, interalar width, internostril width, columella length and nasal tip projection. Results: Postoperative interalar and internostril widening was significant for all categories of maxillary movement. However, there was little significant relation in all parameters between the amount and direction of maxillary movement. Interestingly, movement of the maxilla with upward did show a little decrease in the columellar angle, supra tip break angle and nasolabial angle. Also movement of the maxilla with forward did show a little advancement in the upper lip position. Conclusion: Changes to the nose clearly occur after orthognathic surgery. There was a significant increase in postoperative interalar width and internostril width with maxillary movement. However, no clear correlation could be determined between amount of change and maxillary movement. Interestingly, maxillary impaction did show a little decrease in the columellar angle, supra tip break angle and nasolabial angle. In addition, we used 3D-CT for more precise analysis as a useful tool.

• Biomolecules & Therapeutics
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• v.23 no.2
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• pp.195-200
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• 2015

We tested the hypothesis that micro-computed tomography (micro-CT) analysis provides a better quantitative readout of the therapeutic potential of methotrexate (MTX) for treating collagen-induced arthritis (CIA) in rats and compared to conventional histopathological examination. Rats were divided into three groups: Group 1 (G1) was treated with 0.9% saline, whereas groups 2 (G2) and 3 (G3) were boosted with type II collagen at days 0 and 7. Following the first collagen immunization, rats in G1 and G2 were treated with 0.9% saline and those in G3 were treated with 1.5 mg/kg MTX from day 14 to 28. All rats were sacrificed on day 28, at which point and all hind knee joints were analyzed by micro-CT and histopathological examination. Micro-CT analyses showed that bone volume and trabecular number were significantly decreased in G2 and G3 compared to G1 (p<0.01), as was percent bone volume (p<0.05 and p<0.01, respectively). However, bone surface/bone volume was significantly increased in G2 and G3 compared to G1 (p<0.05 and p<0.01, respectively). Trabecular separation was significantly increased in G3 compared to G1 (p<0.05). Histopathological examination showed that knee joints of rats in G2 and G3 showed severe joint destruction with inflammatory cell infiltration. However, cartilage destruction was slightly reduced in G3 compared to G2. Taken together, these results suggest that MTX treatment reduced cartilage destruction in rats with CIA, and micro-CT analyses made it possible to quantify arthritic bony lesion.

• Journal of Korean Neurosurgical Society
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• v.59 no.6
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• pp.544-550
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• 2016

Objective : Cerebral endothelial cells have unique biological features and are fascinating candidate cells for stroke therapy. Methods : In order to understand the molecular mechanisms of human cerebral endothelial cell (hCMEC/D3) transplantation in a rat stroke model, we performed proteomic analysis using 2-dimensional electrophoresis and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. Protein expression was confirmed by quantitative real-time PCR and Western blot. Results : Several protein spots were identified by gel electrophoresis in the sham, cerebral ischemia (CI), and CI with hCMEC/D3 treatment cerebral ischemia with cell transplantation (CT) groups, and we identified 14 differentially expressed proteins in the CT group. Proteins involved in mitochondrial dysfunction (paraplegin matrix AAA peptidase subunit, SPG7), neuroinflammation (peroxiredoxin 6, PRDX6), and neuronal death (zinc finger protein 90, ZFP90) were markedly reduced in the CT group compared with the CI group. The expression of chloride intracellular channel 4 proteins involved in post-ischemic vasculogenesis was significantly decreased in the CI group but comparable to sham in the CT group. Conclusion : These results contribute to our understanding of the early phase processes that follow cerebral endothelial cell treatment in CI. Moreover, some of the identified proteins may present promising new targets for stroke therapy.

• Archives of Plastic Surgery
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• v.32 no.4
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• pp.467-473
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• 2005

Calvarial bone grafting in craniomaxillofacial trauma and facial reconstructive surgery is now widely recognized and accepted as a standard procedure. One of the commonly reported problems of calvarial bone graft is the contour defect caused by partial resorption of the graft. But, there are few reports that discuss the fate of the calvarial bone graft based on the quantitative data. In this article, the changes of grafted calvarial bone were evaluated using 3-dimensional computed tomography(CT). 9 patients were observed with the CT scans at 2mm thickness immediately after operation and at the time of last follow-up. The area of the bone defect was segmented on the 3-dimensional CT image and calculated by AnalyzeDirect 5.0 software. The immediate postoperative bone defect area of the recipient site and the donor site were $612.9mm^2$ and $441.5mm^2$, respectively, which became $1028.1mm^2$ and $268.8mm^2$, respectively at the last follow-up. In conclusion, the bone defect area was less increased on the donor site of calvarial bone graft than on the recipient site. And the CT scan is a valuable imaging method to assess and follow-up the clinical outcome of calvarial bone grafting.

• Development and Reproduction
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• v.14 no.4
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• pp.261-268
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• 2010

As in the O. mykiss electrophoretic profiles of RNA, the signals of each RNA sample from 9 individual tissues such as liver, muscle, brain, heart, pituitary gland, kidney, intestine, spleen and gill similar to positive control were obtained. The tissue distributions of the complimentary DNA (cDNA) of O. mykiss four genes were analyzed using quantitative real-time PCR with primer sets for tissue expression analysis. In this rainbow trout species, author obtained bands of various sizes, ranged from 700 bp to 1,400 bp. A dissociation curve was made at the end of each run to make sure that there was no non-specific amplification. Supplementarily, the Ct of each DNA was compared. The Ct values of vinculin with rainbow trout tissues were determined in a manner similar to those for agouti-related protein (AgRP) and melanocortin receptors (MC4R I and MC4R II). Further, obtained Cts for standard curve of each DNA were affected by specific product (vinculin, AgRP and MC4R II genes). After several experiments with four individual genes of rainbow trout, author estimated a variation ratio of the mean Ct value of the DNA extracted using the comparative CTt method was 37.27, and the standard deviation was 5.33. The correlation coefficient between the Ct values and the concentration of cDNA was -0.98, -0.99, -0.91 and -0.86, respectively (vinculin, AgRP, MC4R I and MC4R II genes). Since this correlation showed high linearity, the straight line obtained was used as a standard for the O. mykiss tissues reared in aquarium. A PCR efficiency of 100% is ideally achieved when the slopes are close to the theoretical value of -3.31. According to quantification method, the results of quantification are strongly affected by the DNA fragmentation. The size of most DNA fragments obtained from various tissues of rainbow trout used in the experiment was approximately 100 bp. According to the four slopes, an efficiency of nearly 100% was estimated for four genes detection methods. Additionally, further analysis with more individuals and primers will be required to fully establish optimization in rainbow trout.