• Journal of Chest Surgery
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• v.32 no.10
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• pp.930-934
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• 1999

Background: The purpose of this study is to analyze the clinical results ad operative compatability by Ravitch methods with pectus excavatum. Material and Method: From 1984 to 1997, were performed Ravitch operations in 40 patients of pectus excavatum and analyzed the effects of correction and postoperative complication according to time of operation retrospectively. The group comprised 35 mem and women whose mean age was 8.9$\pm$7.9 years(between 2 to 35 years). All patients had corrected with Ravitch operation or its modified operation. Modified fixations were accomplished with K-wire in 15 patients and internal plate in 2 and the materials were removed 3 months after operation. The result of correction was estimated with the degree of changed distance between inner surface of sternal body and vertebral in 3 months after correction. Result: Postoperative complications were wound disruption in 14 patients. Estimated distances after correction ranged 0.4 cm to 4 cm. The acceptability for chest wall correction was high(6 excellent, 29 good in criteria of Humphreys). Conclusion: We concluded that the benefits of Ravitch operation were a high acceptability of patients and their family, and sufficient correction with no specific complications related operation.

• Journal of Institute of Control, Robotics and Systems
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• v.18 no.3
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• pp.224-229
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• 2012

In this paper, we propose a correction method for astronomical telescope using recursive least square method. There are two ways to move a telescope : equatorial operation and altazimuth operation. We must align polar axis of a equatorial telescope with the north celestial pole and adjust the horizontal axis of a altazimuth telescope exactly to match the celestial coordinate system with the telescope coordinate system. This process needs time and expertise. We can skip existing process and correct a tracking error easily by deriving the relationship of the celestial coordinate system and the telescope coordinate system using the proposed correction method. We obtain the coordinate of a celestial body in the celestial coordinate system and the telescope coordinate system and derive a transformation matrix through the obtained coordinate. We use recursive least square method to estimate the unknown parameters of a transformation matrix. Finally, we implement a telescope control system using a microprocessor and verify the performance of the correction method. Through an experiment, we show the validity of the proposed correction method.

• The Journal of Korean Society for Radiation Therapy
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• v.18 no.2
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• pp.89-96
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• 2006

Purpose: To study effectiveness of heterogeneity correction of internal-body inhomogeneities and patient positioning immobilizers in dose calculation, using images obtained from CT-Simulator. Materials and Methods: A water phantom($250{\times}250{\times}250mm^3$) was fabricated and, to simulate various inhomogeneity, 1) bone 2) metal 3) contrast media 4) immobilization devices(Head holder/pillow/Vac-lok) were inserted in it. And then, CT scans were peformed. The CT-images were input to Radiation Treatment Planning System(RTPS) and the MUs, to give 100 cGy at 10 cm depth with isocentric standard setup(Field Size=$10{\times}10cm^2$, SAD=100 cm), were calculated for various energies(4, 6, 10 MV X-ray). The calculated MUs based on various CT-images of inhomogeneities were compared and analyzed. Results: Heterogeneity correction factors were compared for different materials. The correction factors were $2.7{\sim}5.3%$ for bone, $2.7{\sim}3.8%$ for metal materials, $0.9{\sim}2.3%$ for contrast media, $0.9{\sim}2.3%$ for Head-holder, $3.5{\sim}6.9%$ for Head holder+pillow, and $0.9{\sim}1.5%$ for Vac-lok. Conclusion: It is revealed that the heterogeneity correction factor calculated from internal-body inhomogeneities have various values and have no consistency. and with increasing number of beam ports, the differences can be reduced to under 1%, so, it can be disregarded. On the other hand, heterogeneity correction from immobilizers must be regarded enough to minimize inaccuracy of dose calculation.

• Progress in Medical Physics
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• v.17 no.4
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• pp.246-251
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• 2006

The purpose of this study was to evaluate SUV (standard uptake value) using different reconstruction methods in whole body PET/CT Imaging. PET/CT studies were peformed with and without correction for effect of contrast media. The patients data were acquired using GE DSTe commercial PET/CT system. The liver disease (hepatocellular carcinoma, HCC) and renal disease (renal ceil carcinoma, RCC) patients were selected for this study, The PET/CT data were reconstructed using post CT scan with and without correction for effect of contrast media. We selected ROIs (region of Interest) at the same location and same area for the same patient to compare SUVs in these two methods. For HCC and RCC, the average differences of SUVs were measured as $1.5{\pm}1.2%\;and\;1.0{\pm}0.9%$, respectively. For HCC and RCC, the maximum differences of SUVs were measured as 4.3% and 1.9%, respectively. We observed that SUVs without correction for effect of contrast media were higher than SUVs with correction for effect of contrast media. However the differences of SUVs were very minimal. These results may be limited to HCC and RCC and further studies will be Heeded for other organs or diseases to see any changes in SUV with and without correction for effect of contrast media.

• Progress in Medical Physics
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• v.31 no.4
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• pp.189-193
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• 2020

An MR-based attenuation correction (MRAC) map plays an important role in quantitative positron emission tomography (PET) image evaluation in PET/magnetic resonance imaging (MRI) systems. However, the MRAC map is affected by the magnetic field inhomogeneity of MRIs. This study aims to evaluate the characteristics of MRAC maps of physical phantoms on PET/MRI images. Phantom measurements were performed using the Siemens Biograph mMR. The modular type physical phantoms that provide assembly versatility for phantom construction were scanned in a four-channel Body Matrix coil. The MRAC map was generated using the two-point Dixon-based segmentation method for whole-body imaging. The modular phantoms were scanned in compact and non-compact assembly configurations. In addition, the phantoms were scanned repeatedly to generate MRAC maps. The acquired MRAC maps show differently assigned values for void areas. An incorrect assignment of a void area was shown on a locally compact space between phantoms. The assigned MRAC values were distorted using a wide field-of-view (FOV). The MRAC values also differed after repeated scans. However, the erroneous MRAC values appeared outside of phantom, except for a large FOV. The MRAC map of the phantom was affected by phantom configuration and the number of scans. A quantitative study using a phantom in a PET/MRI system should be performed after evaluation of the MRAC map characteristics.

• Journal of the Korean Society of Clothing and Textiles
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• v.47 no.3
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• pp.531-543
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• 2023

Unlike a still body in a photograph, the concept of time applies to a moving body wearing clothes. Clothes change shape according to movement, and multidimensional formative observation elements are required to perceive this. Thus, the purpose of this research is to develop a system for observing body movements and clothing. This experimental study was designed based on embodiment research. The first stage of the study derived body movement and clothing observation items from theory. In the second stage, 11 fashion personnel participated in experimental research to verify the observation items and identify those that needed correction or supplementation. The results showed that body movement and clothing observation items can be classified as follows: large moving bodies, moving clothes, body and clothes movement, and body and clothes space. The observation system for body movement and clothes presented can be used to construct the formation of moving clothes.

• The Korean Journal of Nuclear Medicine Technology
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• v.14 no.1
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• pp.46-53
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• 2010

Purpose: The static image of nuclear medicine study should be acquired without a motion, however, it is difficult to acquire static image without movement for the serious patients, advanced aged patients. These movements cause decreases in reliability for quantitative and qualitative analysis, therefore re-examination was inevitable in the some cases. Consequently, in order to improve the problem of motion artifacts, the authors substituted the dynamic acquisition technique for the static acquisition, using motion correction. Materials and Methods: A capillary tube and IEC body phantom were used. First, the static image was acquired for 60 seconds while the dynamic images were acquired with a protocol, 2 sec/frame${\times}$30 frames, under the same parameter and the frames were summed up into one image afterwards. Also, minimal motion and excessive motion were applied during the another dynamic acquisition and the coordinate correction was applied towards X and Y axis on the frames where the motion artifact occurred. But the severe blurred images were deleted. Finally, the resolution and counts were compared between the static image and the summed dynamic images which before and after applying motion correction, and the signal of frequency was analysed after frequency spatial domain was transformed into 2D FFT. Supplementary examination, the blind test was performed by the nuclear medicine department staff. Results: First, the resolution in the static image and summed dynamic image without motion were 8.32 mm, 8.37 mm on X-axis and 8.30 mm, 8.42 mm on Y-axis, respectively. The counts were 484 kcounts, 485 kcounts each, so there was nearly no difference. Secondly, the resolution in the image with minimal motion applying motion correction was 8.66 mm on X-axis, 8.85 mm on Y-axis and had 469 kcounts while the image without motion correction was 21.81 mm, 24.02 mm and 469 kcounts in order. So, this shows the image with minimal motion applying motion correction has similar resolution with the static image. Lastly, the resolution in the images with excessive motion applying motion correction were 9.09 mm on X-axis, 8.83 mm on Y-axis and had 469 kcounts while the image without motion correction was 47.35 mm, 40.46 mm and 255 kcounts in order. Although there was difference in counts because of deletion of blurred frames, we could get similar resolution. And when the image was transformed into frequency, the high frequency was decreased by the movement. However, the frequency was improved again after motion correction. In the blind test, there was no difference between the image applying motion correction and the static image without motion. Conclusion: There was no significant difference between the static image and the summed dynamic image. This technique can be applied to patients who may have difficulty remaining still during the imaging process, so that the quality of image can be improved as well as the reliance for analysis of quantity. Moreover, the re-examination rate will be considerably decreased. However, there is a limit of motion correction, more time will be required to successfully image the patients applying motion correction. Also, the decrease of total counts due to deletion of the severe blurred images should be calculated and the proper number of frames should be acquired.

• The Journal of the Korea Contents Association
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• v.15 no.10
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• pp.327-335
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• 2015

Purpose: This study is a descriptive survey to identify the relations of body shape perception, interpersonal problems, and spiritual well-being in late adolescents. Methods: The participants are 116 late adolescents in S and K city. This study was performed using a structured questionnaire from October 12 to November 16, 2012. The collected data were analyzed by t-test, Kruskal-Wallis test, Bonferroni correction, Pearson's correlation coefficient. Results: According to general characteristics of the participants, there were significant differences in body shape perception for gender, religion, experience of weight control, current body mass index, and wanted body mass index. There were significant differences in spiritual well-being for experience of drinking and religion. There was significant negative correlation between interpersonal problems and spiritual well-being. Conclusions: Therefore, nursing interventions will be needed to improve interpersonal problems and abnormal body shape perception and to enhance spiritual well-being of adolescents.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.12 no.8
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• pp.626-631
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• 2002

A modified equation for the evaluation of discomfort of a seated human body exposed to differential vibration at the seat and the floor was proposed in this paper. Through the review and analysis of the preceding studies, effect of phase difference between the seat and the floor vibration on discomfort were quantitatively identified. The phase effect was shown to be governed by not only phase difference between the two vibrations but both their frequency and the magnitude, which means the present equation for the evaluation of perceptual amount of vibration provided by ISO 2631-1 should be modified. The proposed equation was developed such that the correction function was multiplied to the present equation. The correction function consisted of three parts, each of them represented the effect by phase difference, frequency and vibration magnitude on discomfort respectively.

• Journal of the Korean Society of Radiology
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• v.10 no.5
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• pp.359-365
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• 2016

Fluoroscopy is performed when tissue or organ in the human body is examined, and it is used for diagnosis and procedure in back ailments. With regard to fluoroscopy equipment, distortion occurs on the peripheral part of fluoroscopic image rather than on its central part. This study measured distortion factors of vertical spacing ratio and distortion factor of diagonal spacing ratio before and after correction by applying a correction algorithm. According to measuring the vertical spacing ratio, post-correction standard deviation decreased by 0.04 in comparison with pre-correction one. Also measuring the diagonal spacing ratio, post-correction standard deviation decreased by 0.06 in comparison with pre-correction one. Consequently, the distortion of fluoroscopic image decreased after correction. A decrease in the distortion of image through the application of correction algorithm and the improvement of performance will be helpful in finding a correct position of lumbar puncture in nucleoplasty to treat lumbar disc herniation in the future.