• The korean journal of orthodontics
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• v.26 no.2 s.55
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• pp.153-162
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• 1996

Rapid maxillary expansion is widely used for the correction of anteroposterior discrepancies, constriction of the maxillary arch, etc. This experiment was undertaken to examine the serial changes in the osteogenesis as well as the collagen fiber bundles in the intermaxillary suture during the rapid maxillary expansion treatment. Four young female dogs aged 6 to 8 months old and not showing menarche yet were used for the experiment. The maxillary impression of dogs were taken, expansion device cast and Hyrax screw soldered at the midline in the 1st premolar area. RME device was delivered to the dogs and the activation of 0.25 mm per quarter-turn was done 2 times per day for 10 days until 5 mm separation was made. Separation of the maxilla was confirmed by X-ray. The animals were sacrificed on 0, 15, 30, 60 days from the finish of maxillary separation and preparations for light microscopy and surface electron microscopy were made. The sutures were cut into frontal serial sections for examination of the histological reactions. The following results were obtained and the conclusions made. 1. The edges of the two palatal plates bordering the midpalatal suture which at the beginning of the retention period were mainly composed of compact bone, underwent extensive resorption followed by new bone formation and gradually became spongy bone rich in bone marrow which in the 60 day retention animal became the compact bone with short intermaxillary suture space. During this transformation, newly formed trabecular bone tissues were added to the original margin. 2. Throughout the expansion period, the collagen fibers underwent successive changes such as stretching, loss of polarity, and finally fibrillogenesis. Towards the end of the expansion procedure, sharpey's fiber formation in newly formed bones were observed. 3. Bony spicules were found in the initial stage of retention on occlusal topographic X-rays, which later were confirmed to have ossified. 4. Judging from the histological changes occuring during the experimental expansion, excessive expansion will cause an excessive bleeding, and retard the remodeling of intermaxillary suture. According to the above results, the bone remodeling after rapid maxillary expansion was preceded by the migration of migratory cells into the intermaxillary suture area. The bone remodeling phenomena were on-going during the 2 months retention sample.

• Progress in Medical Physics
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• v.24 no.4
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• pp.237-242
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• 2013

In the intracranial regions, an accurate delineation of the target volume has been difficult with only the CT data due to poor soft tissue contrast of CT images. Therefore, the magnetic resonance images (MRI) for the delineation of the target volumes were widely used. To calculate dose distributions with MRI-based RTP, the electron density (ED) mapping concept from the diagnostic CT images and the pseudo CT concept from the MRI were introduced. In this study, the look up table (LUT) from the fifteen patients' diagnostic brain MRI images was created to verify the feasibility of MRI-based RTP. The dose distributions from the MRI-based calculations were compared to the original CT-based calculation. One MRI set has ED information from LUT (lMRI). Another set was generated with voxel values assigned with a homogeneous density of water (wMRI). A simple plan with a single anterior 6MV one portal was applied to the CT, lMRI, and wMRI. Depending on the patient's target geometry for the 3D conformal plan, 6MV photon beams and from two to five gantry portals were used. The differences of the dose distribution and DVH between the lMRI based and CT-based plan were smaller than the wMRI-based plan. The dose difference of wMRI vs. lMRI was measured as 91 cGy vs. 57 cGy at maximum dose, 74 cGt vs. 42 cGy at mean dose, and 94 cGy vs. 53 at minimum dose. The differences of maximum dose, minimum dose, and mean dose of the wMRI-based plan were lower than the lMRI-based plan, because the air cavity was not calculated in the wMRI-based plan. These results prove the feasibility of the lMRI-based planning for brain tumor radiation therapy.

• KDI Journal of Economic Policy
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• v.34 no.3
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• pp.1-29
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• 2012

Based on the spatial and land price data of innovation cities and their periphery areas in Korea, this study examines the degree and timing of changes in land price in relation to projects concerning innovation city. The study result confirms that the current system is inconsistent with the principle of restitution of development gain and therefore, this study attempts to seek improvement measures so that the current system can better fit the principle. The analysis reveals that most innovation cities, excluding Sinseo-dong of Daegu and Ujeong-dong of Ulsan, recorded a statistically significant increase in land prices since 2005, compared to those of their neighboring areas. It can be said that the information related to projects concerning innovation city was reflected in the land price since 2005. However, the standard land price pursuant to Article 70 of the Land Compensation Act is the officially assessed land price released on 1st of January 2007, and this official land price was actually applied to the compensation process. Therefore, estimating the compensation amount for land expropriation based on this land price will contradict the principle of restitution of development gain. In other words, despite the fact that development-related information was already reflected in land prices of innovation cities from 2005 to the end of 2006, the compensation process were carried out without institutional arrangements or efforts to exclude such reflection. To solve this problem, this study makes two suggestions. First, it is necessary to cast aside the limitations of the official land price that can be retroactively applied in accordance with Paragraph 5 of Article 70 of the Land Compensation Act, and instead apply the land price which is the most latest but deemed to have no reflection of development gains. Based on this revised standard land price, if the compensation amount is corrected by the average inflation rate and the average rate of increase in land price during the period until the time of the recognized land price, the amount would better satisfy the principle of restitution of development gain. Second, it is necessary to clearly stipulate the standards of development gains being reflected on the land price by including it in the secondary legislation. Under the current system, it is highly likely that appraiser's arbitrary interpretation on development gains is included in the process of calculating the amount of compensation for land expropriation. In this regard, it is necessary to improve the standards on determining whether development gains are reflected based on the results of this academic research and the existing guidelines for appraisal of compensation for land expropriation published by the Korea Association of Property Appraisers.

• Radiation Oncology Journal
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• v.20 no.3
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• pp.283-293
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• 2002

Purpose : A PC based brachytherapy planning system was developed to display dose distributions on simulation images by 2D isodose curve including the dose profiles, dose-volume histogram and 30 dose distributions. Materials and Methods : Brachytherapy dose planning software was developed especially for the Ir-192 source, which had been developed by KAERI as a substitute for the Co-60 source. The dose computation was achieved by searching for a pre-computed dose matrix which was tabulated as a function of radial and axial distance from a source. In the computation process, the effects of the tissue scattering correction factor and anisotropic dose distributions were included. The computed dose distributions were displayed in 2D film image including the profile dose, 3D isodose curves with wire frame forms and dosevolume histogram. Results : The brachytherapy dose plan was initiated by obtaining source positions on the principal plane of the source axis. The dose distributions in tissue were computed on a $200\times200\;(mm^2)$ plane on which the source axis was located at the center of the plane. The point doses along the longitudinal axis of the source were $4.5\~9.0\%$ smaller than those on the radial axis of the plane, due to the anisotropy created by the cylindrical shape of the source. When compared to manual calculation, the point doses showed $1\~5\%$ discrepancies from the benchmarking plan. The 2D dose distributions of different planes were matched to the same administered isodose level in order to analyze the shape of the optimized dose level. The accumulated dose-volume histogram, displayed as a function of the percentage volume of administered minimum dose level, was used to guide the volume analysis. Conclusion : This study evaluated the developed computerized dose planning system of brachytherapy. The dose distribution was displayed on the coronal, sagittal and axial planes with the dose histogram. The accumulated DVH and 3D dose distributions provided by the developed system may be useful tools for dose analysis in comparison with orthogonal dose planning.

• The Journal of Korean Society for Radiation Therapy
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• v.30 no.1_2
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• pp.41-47
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• 2018

Purpose : The purpose of this study is to evaluate the usefulness of 6 Dimensional Skull Tracking(6DST) in Cyberknife Stereotactic Body Radiation Therapy(SBRT) for the first and second cervical vertebrae(C1 and C2) metastasis. Methode and material : The Computed Tomography (Lightspeed VCT 64, General Electric Co. Waukesha, WI, USA) was used to acquire the CT images of the 9 patients with cervical vertebrae(C1 and C2) metastasis. Treatment plans for Xsight spine tracking and 6 Dimensional skull tracking were established with planning system (Multiplan system Version 4.6, Accuray, US). The results of XST and 6DST for each patient were analyzed with Microsoft Excel 2010. Result : The Maximum offsets of XST for C1 were 0.9 mm in Y(supero-inferior), 0.9 mm in Z(antero-posterior), 0.7 mm in X(left-right) direction, and rotations were and 1.0 degrees roll, 1.0 degrees pitch and 1.2 degrees yaw. The Maximum offsets of 6DST for C1 were 0.7 mm, 0.7 mm, 0.9 mm and $1.0^{\circ}$, $1.0^{\circ}$, $1.2^{\circ}$ for Y, Z, X and Roll, Pitch, Yaw. The Maximum offsets of XST and 6DST for C2 were 0.7 mm, 0.7 mm, 0.8 mm and $0.9^{\circ}$, $1.0^{\circ}$, $1.8^{\circ}$, and 0.9 mm, 0.7 mm, 0.9 mm and $0.9^{\circ}$, $0.9^{\circ}$, $1.0^{\circ}$ for Y, Z, X and Roll, Pitch, Yaw, respectively. Conclusion : XST and 6DST showed identical results for translations and rotations within the tolerance. It is possible to simplify the treatment time and procedure by using the 6DST. Therefore, 6DST is very useful methode with XST among the various tracking methods in Cyberknife for the patients with C1, C2 vertebral metastasis.

• Journal of Bio-Environment Control
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• v.30 no.4
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• pp.419-428
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• 2021

In order to develope a mobile-based greenhouse energy calculation program, firstly, the overall thermal transmittance of 10 types of major covers and 16 types of insulation materials were measured. In addition, to estimate the overall thermal transmittance when the cover and insulation materials were installed in double or triple layers, 24 combinations of double installations and 59 combinations of triple installations were measured using the hotbox. Also, the overall thermal transmittance value for a single material and the thermal resistance value were used to calculate the overall thermal transmittance value at the time of multi-layer installation of covering and insulating materials, and the linear regression equation was derived to correct the error with the measured values. As a result of developing the model for estimating thermal transmittance when installing multiple layers of coverings and insulating materials based on the value of overall thermal transmittance of a single-material, the model evaluation index was 0.90 (good when it is 0.5 or more), indicating that the estimated value was very close to the actual value. In addition, as a result of the on-site test, it was evaluated that the estimated heat saving rate was smaller than the actual value with a relative error of 2%. Based on these results, a mobile-based greenhouse energy calculation program was developed that was implemented as an HTML5 standard web-based mobile web application and was designed to work with various mobile device and PC browsers with N-Screen support. It had functions to provides the overall thermal transmittance(heating load coefficient) for each combination of greenhouse coverings and thermal insulation materials and to evaluate the energy consumption during a specific period of the target greenhouse. It was estimated that an energy-saving greenhouse design would be possible with the optimal selection of coverings and insulation materials according to the region and shape of the greenhouse.

• Tuberculosis and Respiratory Diseases
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• v.44 no.1
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• pp.25-43
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• 1997

Introduction : The outcome and incidence of acute respiratory distress syndrome (ARDS) could be variable related to the varied definitions used for ARDS by researchers. The purpose of the national survey was to define the risk factors of ARDS and investigate the prognostic indicies related to mortality of ARDS in Korea according to the definition of ARDS determined by the American-European Concensus Conference on 1992 year. Methods : A Multicenter registry of 48 University or University-affliated hospital and 18 general hospital s equipped with more than 400 patient's beds conducted over 13 months of patients with acute respiratory distress syndrome using the same registry protocol. Results : 1. In the 12 months of the registry, 167 patients were enrolled at the 24 hospitals. 2. The mean age was 56.5 years (${\pm}17.2$ years) and there was a 1.9:1 ratio of males to females. 3. Sepsis was the most common risk factors (78.1%), followed by aspiration (16.6%), trauma (11.6%), and shock (8.5%). 4 The overall mortality rate was 71.9%. The mean duration was 11 days (${\pm}13.1$ days) from the diagnosis of ARDS to the death. Respiratory insufficiency appeared to be a major cause in 43.7% of the deaths followed by sepsis (36.1%), heart failure (7.6%) and hepatic failure (6.7%). 5. There were no significant differences in mortality based on sex or age. No significant difference in mortality in infectious versus noninfectious causes of ARDS was found. 6. There were significant differences in the pulse rate, platelet numbers, serum albumin and glucose levels, the amounts of 24 hour urine, arterial pH, $Pa0_2$, $PaCO_2$, $Sa0_2$, alveolar-arterial oxygen differences, $PaO_2/FIO_2$, and PEEP/$FI0_2$ between the survivors and the deaths on study days 1 through 6 of the first week after enrollment. 7. The survivors had significantly less organ failure and lower APACHE III scores at the time of diagnosis of ARDS (P<0.05). 8. The numbers of organ failure (odd ratio 1.95, 95% confidence intervals:1.05-3.61, P=0.03) and the score of APACHE III (odd ratio 1.59, 95% confidence interval:1.01-2.50, P=0.04) appeared to be independent risk factors of the mortality in the patients with ARDS. Conclusions : The mortality was 71.9% of total 167 patients in this investigation using the definition of American-European Consensus Conference on 1992 year, and the respiratory insufficiency was the leading cause of the death. In addition, the numbers of organ failure and the score of APACHE III at the time of diagnosis of ARDS appeared to be independent risk factors of the mortality in the patients with ARDS.

• Progress in Medical Physics
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• v.18 no.2
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• pp.81-86
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• 2007

The cone-beam CT (CBCT) which is acquired using on-board imager (OBI) attached to a linear accelerator is widely used for the image guided radiation therapy. In this study, the effect of respiratory motion on the quality of CBCT image was evaluated. A phantom system was constructed in order to simulate respiratory motion. One part of the system is composed of a moving plate and a motor driving component which can control the motional cycle and motional range. The other part is solid water phantom containing a small cubic phantom ($2{\times}2{\times}2cm^3$) surrounded by air which simulate a small tumor volume in the lung air cavity CBCT images of the phantom were acquired in 20 different cases and compared with the image in the static status. The 20 different cases are constituted with 4 different motional ranges (0.7 cm, 1.6 cm, 2.4 cm, 3.1 cm) and 5 different motional cycles (2, 3, 4, 5, 6 sec). The difference of CT number in the coronal image was evaluated as a deformation degree of image quality. The relative average pixel intensity values as a compared CT number of static CBCT image were 71.07% at 0.7 cm motional range, 48.88% at 1.6 cm motional range, 30.60% at 2.4 cm motional range, 17.38% at 3.1 cm motional range The tumor phantom sizes which were defined as the length with different CT number compared with air were increased as the increase of motional range (2.1 cm: no motion, 2.66 cm: 0.7 cm motion, 3.06 cm: 1.6 cm motion, 3.62 cm: 2.4 cm motion, 4.04 cm: 3.1 cm motion). This study shows that respiratory motion in the region of inhomogeneous structures can degrade the image quality of CBCT and it must be considered in the process of setup error correction using CBCT images.