• Title/Summary/Keyword: Positron Emission Tomography(PET)

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Utility of FDG PET/CT Scans on Extracapsular Spread of Squamous Cell Carcinoma in the Larynx (후두 편평상피암종의 림프절 피막외 침범에 대한 FDG PET/CT 영상의 유용성)

  • Joo, Young-Hoon;Yoo, Ie-Ryung;Cho, Kwang-Jae;Song, Jee-Nam;Yoo, Dong-Joon;Lee, Ho-Suk;Kim, Min-Sik
    • Korean Journal of Head & Neck Oncology
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    • v.28 no.2
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    • pp.118-121
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    • 2012
  • Backgrounds : To evaluated the use of FDG PET/CT for the identification of extracapsular spread(ECS) with histologic correlation in laryngeal cancer. Methods : We reviewed 79 medical records of patients who underwent of FDG PET/CT for laryngeal cancer before surgery. Results : ECS was present in 41.9%(18/43) dissected necks and in 34.5%(20/58) dissected cervical levels. There was a significant difference in the SUVmax between cervical lymph nodes with ECS and without ECS($6.39{\pm}4.53$ vs. $1.19{\pm}1.64$, p<0.001). The cut-off value for the SUVmax for differentiating with ECS from without ECS was 2.8 with the sensitivity of 85.7% and the specificity of 85.6%. Conclusion : The median SUVmax cut-off values of FDG PET/CT higher than 2.8 was associated with greater risk cervical lymph node metastasis with ECS in patients with laryngeal cancer.

Brain Neuroadaptative Changes in Adolescents with Internet Addiction : An FDG-PET Study with Statistical Parametric Mapping Analysis

  • Koo, Young-Jin;Paeng, Jin-Chul;Joo, Eun-Jeong;Kang, Hye-Jin;Im, Youn-Seok;Seok, Ju-Won;Kang, Ung-Gu
    • Journal of the Korean Academy of Child and Adolescent Psychiatry
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    • v.19 no.1
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    • pp.13-18
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    • 2008
  • Objectives : Internet addiction or pathologic internet use is one of the major mental health problems in children and adolescents in Korea. Internet addiction is defined as uncontrollable, markedly time-consuming internet use, which lasts for a period of at least six months. Internet addiction results in poor academic performance and negative parent-child relationships. By using $^{18}F$-fluorodeoxyglucose-positron emission tomography (FDG-PET), we investigated the effects of internet addiction on functional changes occurring in the adolescent brain. Methods : Adolescent patients with an internet addiction (4 boys and 2 girls; $15.6{\pm}1.2$ years) participated in this study. Eight healthy young adults (5 males and 3 females; 18-30 years old) with no previous history of psychiatric illness also participated as normal controls. Brain FDG-PET data was obtained with the participants in the resting condition and with no addictive stimuli. Results : Statistic parametric mapping analysis of the brain FDG-PET data revealed hypometabolic changes in the visual information processing circuits and hypermetabolic changes in the prefrontal areas in the adolescents with internet addiction, as compared with normal controls (p<.001). Conclusion : These results suggest a neuronal adaptation to excessive visual stimulation and synaptic plasticity due to internet addiction.

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Molecular Imaging in the Age of Genomic Medicine

  • Byun, Jong-Hoe
    • Genomics & Informatics
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    • v.5 no.2
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    • pp.46-55
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    • 2007
  • The convergence of molecular and genetic disciplines with non-invasive imaging technologies has provided an opportunity for earlier detection of disease processes which begin with molecular and cellular abnormalities. This emerging field, known as molecular imaging, is a relatively new discipline that has been rapidly developed over the past decade. It endeavors to construct a visual representation, characterization, and quantification of biological processes at the molecular and cellular level within living organisms. One of the goals of molecular imaging is to translate our expanding knowledge of molecular biology and genomic sciences into good patient care. The practice of molecular imaging is still largely experimental, and only limited clinical success has been achieved. However, it is anticipated that molecular imaging will move increasingly out of the research laboratory and into the clinic over the next decade. Non-invasive in vivo molecular imaging makes use of nuclear, magnetic resonance, and in vivo optical imaging systems. Recently, an interest in Positron Emission Tomography (PET) has been revived, and along with optical imaging systems PET is assuming new, important roles in molecular genetic imaging studies. Current PET molecular imaging strategies mostly rely on the detection of probe accumulation directly related to the physiology or the level of reporter gene expression. PET imaging of both endogenous and exogenous gene expression can be achieved in animals using reporter constructs and radio-labeled probes. As increasing numbers of genetic markers become available for imaging targets, it is anticipated that a better understanding of genomics will contribute to the advancement of the molecular genetic imaging field. In this report, the principles of non-invasive molecular genetic imaging, its applications and future directions are discussed.

Biodistribution and PET imaging of [18F]FMISO in mousecolon cancer xenografted mice

  • Seelam, Sudhakara Reddy;Lee, Ji Youn;Kim, Young Joo;Lee, Yun-Sang;Jeong, Jae Min
    • Journal of Radiopharmaceuticals and Molecular Probes
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    • v.1 no.2
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    • pp.137-144
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    • 2015
  • Hypoxia is an important adverse prognostic factor for tumor progression and is a major cause of failure of radiation therapy. In case of short-term hypoxia, the metabolism can recover to normal, but if hypoxia persists, it causes irreversible cell damage and finally leads to death. So a hypoxia marker would be very useful in oncology. In particular, 2-nitroimidazole can be reduced to form a reactive chemical species, which can bind irreversibly to cell components in the absence of sufficient oxygen, thus, the development of radiolabeled nitroimidazole derivatives for the imaging of hypoxia remains an active field of research to improve cancer therapy result. 2-nitroimidazole based hypoxia marker, [$^{18}F$]FMISO holds promise for the evaluation of tumor hypoxia by Positron emission tomography (PET), at both global and local levels. In the present study, [$^{18}F$]FMISO was synthesized using an automatic synthesis module with high radiochemical purity (>99%) in 60 min. Immunohistochemical analysis using pimonidazole confirmed the presence of hypoxia in xenografted CT-26 tumor tissue. A biodistribution study in CT-26 xenografted mice showed that the increased tumor-to-muscle ratio and tumor-to-blood ratios from 10 to 120 min post-injection. In the PET study, [$^{18}F$]FMISO also showed increased tumor-to-muscle ratios from 10 to 120 min post-injection. In conclusion, this study demonstrates the feasibility and utility of [$^{18}F$]FMISO for imaging hypoxiain mouse colon cancer model using small animal PET.

Characterization of New Avalanche Photodiode Arrays for Positron Emission Tomography

  • Song, Tae-Yong;Park, Yong;Chung, Yong-Hyun;Jung, Jin-Ho;Jeong, Myung-Hwan;Min, Byung-Jun;Hong, Key-Jo;Choe, Yearn-Seong;Lee, Kyung-Han
    • Proceedings of the Korean Society of Medical Physics Conference
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    • 2003.09a
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    • pp.45-45
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    • 2003
  • The aim of this study was the characterization and performance validation of new prototype avalanche photodiode (APD) arrays for positron emission tomography (PET). Two different APD array prototypes (noted A and B) developed by Radiation Monitoring Device (RMD) have been investigated. Principal characteristics of the two APD array were measured and compared. In order to characterize and evaluate the APD performance, capacitance, doping concentration, quantum efficiency, gain and dark current were measured. The doping concentration that shows the impurity distribution within an APD pixel as a function of depth was derived from the relationship between capacitance and bias voltage. Quantum efficiency was measured using a mercury vapor light source and a monochromator used to select a wavelength within the range of 300 to 700 nm. Quantum efficiency measurements were done at 500 V, for which the APD gain is equal to one. For the gain measurements, a pencil beam with 450 nm in wavelength was illuminating the center of each pixel. The APD dark currents were measured as a function of gain and bias. A linear fitting method was used to determine the value of surface and bulk leakage currents. Mean quantum efficiencies measured at 400 and 450 nm were 0.41 and 0.54, for array A, and 0.50 and 0.65 for array B. Mean gain at a bias voltage of 1700 V, was 617.6 for array A and 515.7 for type B. The values based on linear fitting were 0.08${\pm}$0.02 nA 38.40${\pm}$6.26 nA, 0.08${\pm}$0.0l nA 36.87${\pm}$5.19 nA, and 0.05${\pm}$0.00 nA, 21.80${\pm}$1.30 nA in bulk surface leakage current for array A and B respectively. Results of characterization demonstrate the importance of performance measurement validating the capability of APD array as the detector for PET imaging.

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Evaluation of the Radiation Dosage Flowing out of the Hot Cell During Synthesis of 18FDG (18FDG 합성시 핫셀장비 외부로 유출 방사선의 선량 평가)

  • Jung, Hongmoon;Cho, June ho;Jung, Jaeeun;Won, Doyeon
    • Journal of the Korean Society of Radiology
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    • v.7 no.5
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    • pp.365-369
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    • 2013
  • Intravenous injection is administered with radioactive medical isotopes to detect disease on Positron Emission Tomography (PET). In this case, typically, $^{18}FDG$ (Fluorodeoxyglucose) is used as a radioactive medicine. Cassette equipment is needed to synthesize deoxyglucose with $^{18}F$, produced by medical cyclotron. Production of radioactive medicine creates a lot of radiation, thus Hot Cell is used to shield a secondary radiation. We measured the radiation dosage flowing out of the hot cell during synthesis of $^{18}FDG$ or distribution. The purpose of this study is to provide the information of radiation dosage regarding the occupational exposure that unintentionally occurs during the synthesis of $^{18}FDG$. In conclusion, we confirmed the radiation dosage out of the hot cell during the $^{18}FDG$ synthesis. Especially, we observed that the radiation flowed out through the lead window, attached as a view port. Thus, it is considered that the improvement of a lead window is necessary in order to decrease the occupational exposure during the $^{18}FDG$ synthesis.

Application of Differential Expression of Genetic Profiles in Brain Tumors with Variable [$^{18}F$]-fluorodeoxyglucose Uptake

  • Lee, Seung-Ho;Yun, Mi-Jin;Kim, Ki-Nam;Seo, Sang-Hui;Sohn, Sung-Hwa;Kim, Yu-Ri;Kim, Hye-Won;Kim, In-Kyoung;Shim, Boo-Im;Lee, Seung-Min;Kim, Meyoung-Kon
    • Molecular & Cellular Toxicology
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    • v.3 no.3
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    • pp.198-207
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    • 2007
  • [ $^{18}F$ ]-fluorodeoxyglucose (FDG) uptake on positron emission tomography (PET) scan has been found to reflect tumor aggressiveness and prognosis in various types of cancer. In this study, the gene expression profiles of glial tumors were evaluated to determine whether glial tumors with high $^{18}F$-FDG uptake have more aggressive biological potential than with low uptake. Surgical specimens were obtained from the 12 patients with glial tumors (4 males and 8 females, age range 42-68 years). The tumor samples were divided into two groups based on the $^{18}F$-FDG uptake PET scan findings: high $^{18}F$-FDG uptake (n=4) and low $^{18}F$-FDG uptake (n=8). The pathological tumor grade was closely correlated with the $^{18}F$-FDG uptake pattern: Glial tumors with high $^{18}F$-FDG uptake were pathologically Edmondson-Steiner grade III, while those with low uptake were grade II. The total RNA was extracted from the frozen tissues of all glial tumors (n=12), and adjacent non-cancerous tissue (n=3). The gene expression profiles were evaluated using cDNA microarray. The glial tumors with high $^{18}F$-FDG uptake showed increase expression of 15 genes compared to those with low uptake (P<0.005). Nine genes were down-regulated. Gene expression is closely related to cell survival, cell-to-cell adhesion or cell spreading; therefore, glial tumors with high $^{18}F$-FDG uptake appear to have more aggressive biological properties than those with low uptake.

New Trend of Pain Evaluation by Brain Imaging Devices (뇌기능 영상장치를 이용한 통증의 평가)

  • Lee Sung-Jin;Bai Sun-Joon
    • Science of Emotion and Sensibility
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    • v.8 no.4
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    • pp.365-374
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    • 2005
  • Pain has at least two dimensions such as somatosensory qualities and affect and patients are frequently asked to score the intensity of their pain on a numerical pain rating scale. However, the use of a undimensional scale is questionable in view of the belief, overwhelmingly supported by clinical experience as well as by empirical evidence from multidimensional scaling and other sources, that pain has multidimensions such as sensory-discrimitive, motivational-affective and cognitive-evaluative The study of pain has recently received much attention, especially in understanding its neurophysiology by using new brain imaging techniques, such as positron emission tomography(PET) and functional magnetic resonance imaging (fMRI), both of which allow us to visualize brain function in vivo. Also the new brainimaging devices allow us to evaluate the patients pain status and plan To treat patients objectively. Base4 on our findings we presented what are the new brain imaging devices and the results of study by using brain imaging devices.

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A cognitive psychological consideration of Michael Chehov's acting techniques (미카엘 체홉 연기 테크닉에 대한 인지심리학적 고찰)

  • Jin, Hyun-Chung;Cho, Joon-Hui
    • (The) Research of the performance art and culture
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    • no.37
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    • pp.365-389
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    • 2018
  • This research aims to study Michael Chekhov's acting techniques scientifically, because his techniques has been studied only theoretically or empirically. Especially, this study focuses on 'imagination' and 'Psychological Gesture' from the perspective of cognitive psychology. Chekhov thought 'imagination' as the basis and core of all the works of acting. In cognitive psychology, it is called as 'imagery' and means 'a representation of the mind of the object not communicated by the sensory organs currently'. This study starts with defining imagery and takes a brief look at the features and kinds of imagery. Then the researcher will prove scientifically the possibility of training acting using imagery as Chekhov's assertion. For the proof of the validity of imagery, we'll look for the theoretical evidences-functional equivalence hypothesis, psychoneuromuscular theory, symbolic learning theory, psychophygiological information processing-and experimental ones-measurements of cerebral blood flow or event-related potential, experiments with fMRI(functional magnetic resonance imaging) or PET(positron emission tomography). As a result, we can see that imagery is functionally identical to perception and improves fulfillment of cognitive and physical tasks. As proving physical changes can draw out psychological changes(feeling) on the medium of imagery, we can also see the validity of Psychological Gesture. From the above research, even if Chekhov developed the acting techniques only on the basis of his experience, his techniques can be thought as having scientific validity. Though insufficient, this study can be a help for actors or students as they using Chekhov's techniques.

Development and Testing of a Machine Learning Model Using 18F-Fluorodeoxyglucose PET/CT-Derived Metabolic Parameters to Classify Human Papillomavirus Status in Oropharyngeal Squamous Carcinoma

  • Changsoo Woo;Kwan Hyeong Jo;Beomseok Sohn;Kisung Park;Hojin Cho;Won Jun Kang;Jinna Kim;Seung-Koo Lee
    • Korean Journal of Radiology
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    • v.24 no.1
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    • pp.51-61
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    • 2023
  • Objective: To develop and test a machine learning model for classifying human papillomavirus (HPV) status of patients with oropharyngeal squamous cell carcinoma (OPSCC) using 18F-fluorodeoxyglucose (18F-FDG) PET-derived parameters in derived parameters and an appropriate combination of machine learning methods in patients with OPSCC. Materials and Methods: This retrospective study enrolled 126 patients (118 male; mean age, 60 years) with newly diagnosed, pathologically confirmed OPSCC, that underwent 18F-FDG PET-computed tomography (CT) between January 2012 and February 2020. Patients were randomly assigned to training and internal validation sets in a 7:3 ratio. An external test set of 19 patients (16 male; mean age, 65.3 years) was recruited sequentially from two other tertiary hospitals. Model 1 used only PET parameters, Model 2 used only clinical features, and Model 3 used both PET and clinical parameters. Multiple feature transforms, feature selection, oversampling, and training models are all investigated. The external test set was used to test the three models that performed best in the internal validation set. The values for area under the receiver operating characteristic curve (AUC) were compared between models. Results: In the external test set, ExtraTrees-based Model 3, which uses two PET-derived parameters and three clinical features, with a combination of MinMaxScaler, mutual information selection, and adaptive synthetic sampling approach, showed the best performance (AUC = 0.78; 95% confidence interval, 0.46-1). Model 3 outperformed Model 1 using PET parameters alone (AUC = 0.48, p = 0.047) and Model 2 using clinical parameters alone (AUC = 0.52, p = 0.142) in predicting HPV status. Conclusion: Using oversampling and mutual information selection, an ExtraTree-based HPV status classifier was developed by combining metabolic parameters derived from 18F-FDG PET/CT and clinical parameters in OPSCC, which exhibited higher performance than the models using either PET or clinical parameters alone.