• Title/Summary/Keyword: pet

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Positron Emission Computed Tomographs and Image Reconstruction Methods (PET 장치와 화상 재구성법)

  • Lee, Man-Koo
    • Journal of radiological science and technology
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    • v.22 no.1
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    • pp.5-11
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    • 1999
  • This paper reviews recent major activities on instrumentation and methodology of PET. The performance of the PET instrumentation can be expressed by four physical characteristics, 1) spatial resolution, 2) coincidence resolving time, 3) energy resolution, and 4) detection efficiency. The physical and technical aspects of PET systems are briefly discussed along with these characteristics. Toward high resolution PET the recent trend has been to design multiple rings of densely packed detector arrays with scintillators. In order to satisfy the sampling requirement in reconstruction, continuous detector units has been developed. Iterative image reconstruction algorithms have received considerable attention for improvement of both the sampling requirement and image quality toward the stationary PET. Better resolving time improves the maximum true coincidence rate, which is also increased with more detectors placed in coincidence with each other. It suggests that volume PET is promising for enhancement of detection efficiency. The scattered coincidence event rate may be reduced by using detectors with better energy resolution. The use of interplane septa, however, takes over improvement of energy resolution in 2D PET. Energy resolution becomes an important factor for image quality under the condition of septa removal such as volume PET. Toward full utilization of emitting photons, 3D reconstruction incorporating oblique rays has been studied, and volume reconstruction algorithms have been developed. Practical volume PET systems impose heavy burden not only to detector sets and coincidence circuits, but also to computers in the memory requirements and the data processing. In conclusion, there have been many ingenious methods in development of PET instrumentation, which are based on unique capability of PET. They will be expected to overcome technical limitations, and to approach the fundamental limits.

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Clinical Applications of $^{18}F$-FDG PET/CT in Malignant Bone and Soft Tissue Tumors (악성 골 및 연부조직 종양에서 $^{18}F$-FDG PET/CT의 임상적 적용)

  • Shin, Duk-Seop
    • The Journal of the Korean bone and joint tumor society
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    • v.14 no.2
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    • pp.86-94
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    • 2008
  • $^{18}F$-FDG PET/CT has led to advancement in diagnostic imaging, providing correlation of both physiology and anatomic information, and to new and innovative ways to utilize PET/CT imaging for the evaluation of musculoskeletal tumors. Recently, the most widely utilized musculoskeletal application of PET/CT imaging is for the detection and characterization of bone metastases, staging and restaging of primary malignant bone tumors and soft tissue sarcomas. And it is also useful in evaluating response to therapy for malignant musculoskeletal tumors and in detecting local recurrences or distant metastases during follow up. The future likely holds even more unique and potentially quite useful applications of PET/CT imaging for primary bone and soft tissue tumors. This article will review the useful applications of $^{18}F$-FDG PET/CT imaging for evaluating musculoskeletal tumors.

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Effect of Acid and Salt on Weight toss of Polyester (PET) fabric by Sodium Hydroxide (산과 염이 폴리에스터 직물의 알칼리 감량에 미치는 영향)

  • Do, Sung-Guk;Cho, Hwan
    • Textile Coloration and Finishing
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    • v.4 no.3
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    • pp.65-73
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    • 1992
  • To control the hydrolysis rate of PET fabric with NaOH, HCl and $CH_3$COOH(HAc), as regulating reagent, were added to the 0.5 M NaOH solution. The concentrations of acids in 0.5 M NaOH were varied. PET fabrics were treated with aqueous solutions of acids in 0.5 M NaOH under different conditions. The weight loss of PET fabric, the rate of hydrolysis, the apparent activation energy (E$_{\alpha}$), the handle value, the etched surface of treated PET fabric, and the effect of salts such as NaCl, $CH_3$COONa(NaAc), and NH$_4$Cl on the weight loss were discussed. Acids in the aqueous 0.5 M NaOH solution decreased the weight loss of PET fabric bacause of neutralization of OH- and the weight loss of PET fabrics treated with corresponding concentration of aqueous NaOH solution to the concentrations of the aqueous solutions of acids in 0.5 M NaOH was lower than that of PET fabrics treated with aqueous solutions of acids in 0.5 M NaOH. The addition of NaCl to aqueous NaOH solution accelerated the reaction of OH- with PET greatly, the addition of NaAc increased the weight loss slightly, but the addition of NH$_4$Cl decreased the weight loss. It was thought that the very remarkable result that NaCl in aqueous NaOH solution promoted the hydrolysis of PET with NaOH would contribute to the conservation of energy and NaOH in the weight loss finishing process of PET fabric. The etched surface and the handle value of treated PET fabric were independent of the difference in the kinds of acids and salts added.nd salts added.

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Probability Based Risk Evaluation Techniques for the Small-Sized Sea Floater (소형 해상 부유체의 확률 기반 위기평가기법)

  • Yim, Jeong-Bin
    • Journal of Navigation and Port Research
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    • v.36 no.10
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    • pp.795-801
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    • 2012
  • This paper describes theoretical approach methodology for the Probability based risk Evaluation Techniques (PET) to monitor the risk levels of small-sized sea floater as like a yacht pier. The risk decision-making process by risk criteria with five-step scales is the core concepts of PET. These five-step scales are calculated from cumulative probability distribution of response functions for the sea floater motions using closed-form expressions. In addition, The risk decision-making process of PET with the risk criteria is proposed in this work. To verify the usability of PET, simulation experiments are carried out using mimic signals with the electrical specifications of ADIS16405 sensor that is to be use as measurement tool for the floater motions. As results from experiments, the risk evaluation error by PET shows 0.38 levels in maximum 5.0 levels. These results clearly shown that the proposed PET can be use as the monitoring techniques.

Clinical Application of $^{18}F-FDG$ PET in Gastric Cancer (위암에서 $^{18}F-FDG$ PET의 임상 이용)

  • Yun, Mi-Jin;Kim, Tae-Sung;Hwang, Hee-Sung
    • Nuclear Medicine and Molecular Imaging
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    • v.42 no.sup1
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    • pp.39-45
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    • 2008
  • PET or PET/CT detects only less than 50% of early gastric cancer and 62-98% of advanced gastric cancer. Therefore, mass screening programs are recommended for all adults over the age of 40 for early detection and early treatment of gastric cancer through endoscopy or various radiological tests. The most important step after diagnosis of gastric cancer is accurate staging, which mainly evaluates tumor resectability to avoid unnecessary surgery. Important factors that affect tumor resectability are whether the tumor can be separated from adjacent organs or important blood vessels, the extent of lymph node metastasis, presence of peritoneal metastasis, or distant organ metastasis. To evaluate the extent of local tumor invasion, anatomical imaging that has superior spatial resolution is essential. There are a few studies on prognostic significance of FDG uptake with inconsistent results between them. In spite of lower sensitivity for lymph node staging, the specificity of CT and PET are very high, and the specificity for PET tends to be higher than that for CT. Limited data published so far show that PET seems less useful in the detection of lung and bone metastasis. In the evaluation of pleural or peritoneal metastasis, PET seems very specific but insensitive as well. When FOG uptake of primary tumor is low, distant metastasis also tends to show low FDG uptake reducing its detection on PET. There are only a few data available in the evaluation of recurrence detection and treatment response using FDG PET or PET/CT.

The Change of Mechanical Properties of Alkali Hydrolyzed PET Fabric with Tank/Liquor-flow Machine - Bending and Shear Properties - (PET직물의 Tank/Liquor-flow 감량에 의한 역학적 특성변화 -굽힘.전단특성-)

  • 서말용;한선주;김삼수;허만우;박기수;장두상
    • Textile Coloration and Finishing
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    • v.10 no.4
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    • pp.37-44
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    • 1998
  • The purpose of this study was to elucidate the effect of weight loss of polyethylene terephthalate(PET) fabrics on the mechanical properties such as bending and shear. In order to compare the effect of treatment machine on the mechanical properies of treated PET fabrics, PET fabrics were hydrolyzed with NaOH aqueous solution using Tank machine and Liquor flow machine, respectively. The results were as follows : 1. The bending rigidity and shear stiffness of hydrolyzed PET fabric decreased markedly up to about 10% weight loss regardless of treatment machines. At the above 10% weight loss, the variation of these properties is nearly unchanged. In addition, the bending hysteresis and shear hysteresis also showed similar trend. 2. Weft density change of PET fabrics treated with Liquor flow machine decreased by 1pick/inch. It is assumed that this is attributed to the tension during the treatment of Liquor flow machine. On the other hand, the weft density change of PET fabrics treated with Tank machine is scarcely influeneced by the weight loss. While warp density of PET fabrics treated with Liquor flow machine had no change with weight loss, warp density of PET fabrics treated with Tank machine decreased by 6pick/inch due to the tension. 3. The bending rigidity and shear stiffness of PET fabrics hydrolyzed with liquor flow machine slightly higher than with Tank m/c at the above 10% weight loss. It is assumed that this is caused by the increasement of the crossing pressure of warp and weft yarn and contact points of filaments in the yarns. Also, the bending and shear hysteresis of PET fabrics treated with Tank machine were higher than that of liquor flow machine.

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In a Universal Design Viewpoint Usability Evaluation Research to PET Bottle (유니버설 디자인 관점에서의 PET BOTTLE에 대한 사용성 평가 연구)

  • Kim Sang-Sik
    • Proceedings of the Korea Contents Association Conference
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    • 2005.11a
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    • pp.166-169
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    • 2005
  • While use of a pet bottle with use it is light recently and convenient increases quickly, it is used from the child, also diffusing the user to a pet bottle to people of various classes, such as an old person, a woman, a male, the man in the street, and a disabled person. However, those who are standardized on the basis of the common man with the plan energy of a pet bottle, and cannot attain to the standard, That is, a child and a disabled person may be condemned to the vague situation that a lid cannot be opened or a contents thing cannot be drunk without external help. And the characteristic of a material and production which are called PET Even if convenience is emphasized for the cost reduction of COST, a design is chosen easily, and even if it calls it the man in the street, the point of coming to experience a situation with the difficult time of use can be found well. In research of a book, problem derivation which classifies entering school and a preschool man-and-woman child for a child drink for an object first by the viewpoint of universal design paying attention to such problems, and leads the actual use example of a pet bottle was carried out in true heart, and various notional approach was shown by the solution method.

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Multimodality Image Registration and Fusion using Feature Extraction (특징 추출을 이용한 다중 영상 정합 및 융합 연구)

  • Woo, Sang-Keun;Kim, Jee-Hyun
    • Journal of the Korea Society of Computer and Information
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    • v.12 no.2 s.46
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    • pp.123-130
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    • 2007
  • The aim of this study was to propose a fusion and registration method with heterogeneous small animal acquisition system in small animal in-vivo study. After an intravenous injection of $^{18}F$-FDG through tail vain and 60 min delay for uptake, mouse was placed on an acryl plate with fiducial markers that were made for fusion between small animal PET (microPET R4, Concorde Microsystems, Knoxville TN) and Discovery LS CT images. The acquired emission list-mode data was sorted to temporally framed sinograms and reconstructed using FORE rebining and 2D-OSEM algorithms without correction of attenuation and scatter. After PET imaging, CT images were acquired by mean of a clinical PET/CT with high-resolution mode. The microPET and CT images were fusion and co-registered using the fiducial markers and segmented lung region in both data sets to perform a point-based rigid co-registration. This method improves the quantitative accuracy and interpretation of the tracer.

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Physical Property of Heat Storage Knitted Fabrics for High Emotional Garment (고감성 의류용 축열 니트소재의 물성)

  • Kim, Hyun Ah;Heo, Kyoung;Kim, Seung Jin
    • Fashion & Textile Research Journal
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    • v.17 no.2
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    • pp.295-304
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    • 2015
  • This paper investigated wear comfort property of heat storage knitted fabrics for high emotional garment. For this purpose, ZrC imbedded PET knitted fabric was prepared and various physical properties such as thermal, wicking and drying characteristics were measured. In addition, far-infrared emission characteristics of ZrC imbedded PET was analysed and tactile hand property and dye affinity of ZrC imbedded knitted fabric were also studied in comparison with regular and other commercial heat storage PET knitted fabrics. It was observed that Zr imbedded amount in the yarn was 19.29% by ingredient analysis and far-infrared emission energy was $3.65{\times}10^2W/m^2$, emissivity was 0.906 at the range of wavelength $6{\sim}20{\mu}m$. It was found that maximum heat flow (Qmax) of ZrC imbedded PET knitted fabric was lower than that of regular PET one and warmth keepability rate was higher than that of regular PET one, which means ZrC imbedded PET have heat storage property. Drying property of ZrC imbedded knitted fabric was better than that of regular PET one due to heat by far-infrared emitted from ZrC in the core of filament. It revealed that wicking property of the ZrC imbedded fabric was not influenced by far-infrared emission, but affected by fibre physical properties. Tactile hand property of ZrC imbedded knitted fabric was not influenced by imbedding ZrC in the filament but affected preferably by structure of knitted fabric. Dye affinity of ZrC imbedded PET knitted fabric was less influenced by dyeing temperature and time than regular PET knitted one.

A Study on the Effect on the Satisfaction of Pet Hospital (반려동물병원의 이용만족에 미치는 영향에 관한 연구 )

  • Cho, Sung-Min;Ha, Kyu-Soo
    • The Journal of the Korea Contents Association
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    • v.21 no.9
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    • pp.258-269
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    • 2021
  • This study was conducted to determine the effect on the satisfaction of pet hospital. For this research, the study was conducted on customers who raise dogs and cats nationwide and use pet hospital. Specialties, human factors, efficiency, physical factors, and pet satisfaction were derived from factors that affect pet hospital use satisfaction. Human factors included three factors as veterinarian, staff, and pet hairdressers, and regression analysis was performed. Research shows that professional, efficiency, and physical factors have a positive (+) effect on user satisfaction, veterinarians and staff, which are detailed factors of human factors, have a positive (+) effect on user satisfaction, and pet hairdressers do not. Overall, it was analyzed that it affects the satisfaction of use in the order of efficiency, professionalism, staff, veterinarian, pet satisfaction, and physical factors. This study is meaningful in that it divided human factors into occupational groups and developed and analyzed pet satisfaction factors as factors that affect pet hospital use satisfaction, and it is expected that pet hospital can help establish strategies to improve customer satisfaction.