• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.10a
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• pp.240-243
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• 2005

Osteoporosis, one of the age-related disease causes vertebra body fracture due to weakening trabecular bone and makes a substantial effect on load sharing among vertebras. Recently, vertebroplasty is one of the most popular treatment, as augmenting PMMA into vertebra. Biomechanical studies about vertebroplasty have been evaluated by several experiments or analysis under static loading but there has been no study on response under dynamic loading. This study included the FE analysis of patients who treated vertebroplasty under dynamic loading. For this study, 3-D FE model of lumbar spine(L1-L2) was modeled from CT scanning data and compared with experimental results in vitro in order to validate this model. Biomechanical behavior about each of normal person, osteoporotic patient and patient treated vertebroplasty for quantitative evaluations of vertebroplasty was compared and investigated.

• Journal of Digital Convergence
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• v.11 no.9
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• pp.365-370
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• 2013

This mouse calvarial defected model is frequently used for new scaffold development in the bone regeneration. Most experiments are carried out in this way by measuring the bone regeneration of mouse calvaria defected area. As a next step, hematoxylin and eosin staining is analyzed by sacrificing mice On the other hand, the quantitative analysis for bone regeneration is carried out by micro computed tomography. However, there are several drawbacks with the micro computed tomography. That is, it takes a long time and it is quite expensive for bone regeneration quantitative analysis. This study was performed by simply measuring the quantity of bone regeneration in mouse clavaira defected area on two-dimensional digital x-ray images via Image J. Consequentially, this experimental method by using J program might help bio-technologist researcher regarding new bone regeneration by comparing the quantity of bone regeneration quickly and precisely as well.

• Journal of the Mineralogical Society of Korea
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• v.15 no.4
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• pp.329-344
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• 2002

Mineralogical and chemical characterization of some domestic bentonites, such as quantitative XRD analysis, chemical leaching experiments, pH and CEC determinations, were done without any separation procedures to understand their relationships among mineral composition, characteristics, and cation exchange properties. XRD quantification results based on Rietveld method reveal that the bentonites contain totally more than 25 wt% of impurities, such as zeolites, opal-CT, and feldspars, in addition to montmorillonite ranging 30～75 wt%. Cation exchange properties of the zeolitic bentonites are deeply affected by the content of zeolites identified as clinoptilolite-heulandite series. Clinoptilolite is common in the silicic bentonites with lighter color. and occurs closely in association with opal-CT. Ca is mostly the dominant exchangeable cation, but some zeolitic bentonites have K as a major exchangeable cation, The values of cation exchange capacity (CEC) determined by Methylene Blue method are comparatively low and have roughly a linear relationship with the montmorillonite content of the bentonite, though the correlated data tend to be rather dispersed. Compared to this, the CEC determined by Ammonium Acetate method, i.e.‘Total CEC’, has much higher values (50～115 meq/100 g). The differences between those CEC values are much greater in zeolitic bentonites, which obviously indicates the CEC increase affected by zeolite. Other impurities such as opal-CT and feldspars seem to affect insignificantly on the CEC of bentonites. When dispersed in distilled water, the pH of bentonites roughly tends to increase up to 9.3 with increasing the alkali abundance, especially Na, in exchangeable cation composition. However, some bentonites exhibit lower pH (5～6) so as to regard as ‘acid clay’. This may be due to the presence of $H^{＋}$ in part as an exchangeable cation in the layer site of montmorillonite. All the works of this study ultimately suggest that an assesment of domestic bentonites in grade and quality should be accomplished through the quantitative XRD analysis and the ‘Total CEC’measurement.

• The Journal of Korean Society for Radiation Therapy
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• v.24 no.2
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• pp.85-93
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• 2012

Purpose: It is essential to minimize the respiratory-induced motion of involved organs in the Tomotherapy for tumor located in the chest and abdominal region. However, the application of breathing control system to Tomotherapy is limited. This study was aimed to investigate the possible application of the ABCHES system and its efficacy as a means of breathing control in the tomotherapy treatment. Materials and Methods: Five subjects who were treated with a Hi-Art Tomotherapy system for lung, liver, gallbladder and pancreatic tumors. All patients undertook trained on two breathing methodes using an ABCHES, free breathing methode and shallow breathing methode. When the patients could carry out the breathing control, 4D-CT scan was a total of 10 4D tomographic images were acquired. A radiologist resident manually drew the tumor region, including surrounding nomal organs, on each of CT images at the inhalation phase, the exhalation phase and the 40% phase (mid-inhalation) and average CT image. Those CT images were then exported to the Tomotherapy planning station. Data exported from the Tomotherapy planning station was analyzed to quantify characteristics of dose-volume histograms and motion of tumors. Organ motions under free breathing and shallow breathing were examined six directions, respectively. Radiation exposure to the surrounding organs were also measured and compared. Results: Organ motion is in the six directions with more than a 5 mm displacement. A total of 12 Organ motions occurred during free breathing while organ motions decreased to 2 times during shallow breathing under the use of Abches. Based on the quantitative analysis of the dose-volume histograms shallow breathing showed lower resulting values, compared to free breathing, in every measure. That is, treatment volume, the dose of radiation to the tumor and two surrounding normal organs (mean doses), the volume of healthy tissue exposed to radiation were lower at the shallow breathing state. Conclusion: This study proposes that the use of ABCHES is effective for the Tomotherapy treatment as it makes shortness of breathing easy for patients. Respiratory-induced tumor motion is minimized, and radiation exposure to surrounding normal tissues is also reduced as a result.

• The Korean Journal of Nuclear Medicine Technology
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• v.15 no.1
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• pp.10-16
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• 2011

Purpose: The partial volume effect occurs because of limit of the spatial resolution. It makes partial loss of intensity and causes SUV to be lower than it should actually be. So the purpose of this study is to calculate recovery coefficient for correcting PVE from phantom study and to compare before and after SUV correction applying to PET/CT examination. Materials and Methods: The flangeless Esser PET phantom consisting of four hot cylinders was used for this study. All of the hot cylinders were filled with FDG solution of 20.72 MBq per 1000 ml, and the phantom background was filled with FDG solution of different concentrations (33.30, 22.20, 16.65 MBq per 6440 ml) to yield H/B ratios of around 4:1, 6:1 and 8:1. Using the Biograph Truepoint 40(SIEMENS, Germany), we applied recovery coefficient method to 30 patients who were diagnosed with lung cancer after PET/CT exam. And then we analyzed and compared SUV before and after correcting partial volume effect. Results: The smaller the diameter of hot cylinder becomes, the more recovery coefficient decreased. When we applied recovery coefficient to clinical patients and compared SUV before and after correcting PVE, before the correction all lesions gave an average max SUV of 7.83. And after the correction, the average max SUV increases to 10.31. The differences in the max SUV between before and after correction were analyzed by paired t test. As a result, there were statistically significant differences (t=7.21, p=0.000). Conclusion: The SUV for quantification should be measured precisely to give consistent information of tumor uptake. But PVE is one of factors that causes SUV to be lower and to be underestimated. We can correct this PVE and calculate corrected SUV using the recovery coefficient from phantom study. And if we apply this correction method to clinical patients, we can finally assess and provide quantitative analysis more accurately.

• Horticultural Science & Technology
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• v.32 no.6
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• pp.845-852
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• 2014

Among various abiotic stress factors, soil salinity decreases the photosynthetic rate, growth, and yield of plants. Recently, many genes have been reported to enhance salt tolerance. The objective of this study was to characterize the Brassica rapa Salt Stress Resistance (BrSSR) gene, of which the function was unclear, although the full-length sequence was known. To characterize the role of BrSSR, a B. rapa Chinese cabbage inbred line ('CT001') was transformed with pSL94 vector containing the full length BrSSR cDNA. Quantitative real-time polymerase chain reaction (qRT-PCR) analysis showed that the expression of BrSSR in the transgenic line was 2.59-fold higher than that in the wild type. Analysis of phenotypic characteristics showed that plants overexpressing BrSSR were resistant to salinity stress and showed normal growth. Microarray analysis of BrSSR over-expressing plants confirmed that BrSSR was strongly associated with ERD15 (AT2G41430), a gene encoding a protein containing a PAM2 motif (AT4G14270), and GABA-T (AT3G22200), all of which have been associated with salt tolerance, in the co-expression network of genes related to salt stress. The results of this study indicate that BrSSR plays an important role in plant growth and tolerance to salinity.

• Korean Journal of Head & Neck Oncology
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• v.34 no.1
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• pp.21-27
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• 2018

Background/Objectives: This study aimed to evaluate the changes of uptake around the sternoclavicular joint (SCJ) according to 18F-FDG PET images in patients with head and neck cancer who underwent neck dissection. Materials & Methods: Retrospectively, the medical records of patients who received selective or comprehensive neck dissection were reviewed. Preoperative and 1-year postoperative 18F-FDG PET images, if available, were analyzed by nuclear medicine physicians in both qualitative and quantitative manners. Correlation between the changes of uptake around SCJ and perioperative data were statistically analyzed. Results: Thirty-seven patients satisfying the inclusion criteria were enrolled. Seven patients with increased uptake around SCJ on 1-year postoperative 18F-FDG PET showed a correlation with radical or comprehensive neck dissection, accessory nerve sacrifice, and high postoperative SUVmax. When 20 patients with increased uptake around SCJ according to quantitative measurement were compared with other patients without increased uptake, no parameter was significantly different, except postoperative SUVmax. Bivariate logistic regression analysis revealed that the clinical symptom (shoulder or sternal pain) was significantly correlated with the extent of neck dissection (OR 0.227, CI 0.053-0.966, p=0.045) and spinal accessory nerve sacrifice (OR 13.500, CI 1.189-153.331, p=0.036). Conclusions: Increased uptake around SCJ on 1-year postoperative 18 F-FDG PET was correlated with either the radical or comprehensive procedure, as well as with accessory nerve sacrifice. This suggests that subjective analysis of 18F-FDG PET can be used to detect subclinical shoulder instability.

• Journal of the Korean Society of Radiology
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• v.17 no.5
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• pp.663-670
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• 2023

In this study, we aimed to perform a comparative evaluation using quantitative factors between a region-growing based segmentation with noise reduction algorithms and a U-Net based segmentation. Initially, we applied median filter, median modified Wiener filter, and fast non-local means algorithm to computed tomography (CT) images, followed by region-growing based segmentation. Additionally, we trained a U-Net based segmentation model to perform segmentation. Subsequently, to compare and evaluate the segmentation performance of cases with noise reduction algorithms and cases with U-Net, we measured root mean square error (RMSE) and peak signal to noise ratio (PSNR), universal quality image index (UQI), and dice similarity coefficient (DSC). The results showed that using U-Net for segmentation yielded the most improved performance. The values of RMSE, PSNR, UQI, and DSC were measured as 0.063, 72.11, 0.841, and 0.982 respectively, which indicated improvements of 1.97, 1.09, 5.30, and 1.99 times compared to noisy images. In conclusion, U-Net proved to be effective in enhancing segmentation performance compared to noise reduction algorithms in CT images.

• Korean Journal of Radiology
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• v.21 no.9
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• pp.1104-1113
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• 2020

Objective: To assess the regional ventilation in patients with asthma-chronic obstructive pulmonary disease (COPD) overlap syndrome (ACOS) using xenon-ventilation dual-energy CT (DECT), and to compare it to that in patients with COPD. Materials and Methods: Twenty-one patients with ACOS and 46 patients with COPD underwent xenon-ventilation DECT. The ventilation abnormalities were visually determined to be 1) peripheral wedge/diffuse defect, 2) diffuse heterogeneous defect, 3) lobar/segmental/subsegmental defect, and 4) no defect on xenon-ventilation maps. Emphysema index (EI), airway wall thickness (Pi10), and mean ventilation values in the whole lung, peripheral lung, and central lung areas were quantified and compared between the two groups using the Student's t test. Results: Most patients with ACOS showed the peripheral wedge/diffuse defect (n = 14, 66.7%), whereas patients with COPD commonly showed the diffuse heterogeneous defect and lobar/segmental/subsegmental defect (n = 21, 45.7% and n = 20, 43.5%, respectively). The prevalence of ventilation defect patterns showed significant intergroup differences (p < 0.001). The quantified ventilation values in the peripheral lung areas were significantly lower in patients with ACOS than in patients with COPD (p = 0.045). The quantified Pi10 was significantly higher in patients with ACOS than in patients with COPD (p = 0.041); however, EI was not significantly different between the two groups. Conclusion: The ventilation abnormalities on the visual and quantitative assessments of xenon-ventilation DECT differed between patients with ACOS and patients with COPD. Xenon-ventilation DECT may demonstrate the different physiologic changes of pulmonary ventilation in patients with ACOS and COPD.

• Korean Journal of Radiology
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• v.25 no.4
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• pp.384-394
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• 2024

Objective: To evaluate the image quality of novel dark-blood computed tomography angiography (CTA) imaging combined with deep learning reconstruction (DLR) compared to delayed-phase CTA images with hybrid iterative reconstruction (HIR), to visualize the cervical artery wall in patients with Takayasu arteritis (TAK). Materials and Methods: This prospective study continuously recruited 53 patients with TAK (mean age: 33.8 ± 10.2 years; 49 females) between January and July 2022 who underwent head-neck CTA scans. The arterial- and delayed-phase images were reconstructed using HIR and DLR. Subtracted images of the arterial-phase from the delayed-phase were then added to the original delayed-phase using a denoising filter to generate the final-dark-blood images. Qualitative image quality scores and quantitative parameters were obtained and compared among the three groups of images: Delayed-HIR, Dark-blood-HIR, and Dark-blood-DLR. Results: Compared to Delayed-HIR, Dark-blood-HIR images demonstrated higher qualitative scores in terms of vascular wall visualization and diagnostic confidence index (all P < 0.001). These qualitative scores further improved after applying DLR (Dark-blood-DLR compared to Dark-blood-HIR, all P < 0.001). Dark-blood DLR also showed higher scores for overall image noise than Dark-blood-HIR (P < 0.001). In the quantitative analysis, the contrast-to-noise ratio (CNR) values between the vessel wall and lumen for the bilateral common carotid arteries and brachiocephalic trunk were significantly higher on Dark-blood-HIR images than on Delayed-HIR images (all P < 0.05). The CNR values were significantly higher for Dark-blood-DLR than for Dark-blood-HIR in all cervical arteries (all P < 0.001). Conclusion: Compared with Delayed-HIR CTA, the dark-blood method combined with DLR improved CTA image quality and enhanced visualization of the cervical artery wall in patients with TAK.