• 대한기계학회논문집B
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• 제24권6호
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• pp.769-776
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• 2000

Visible spectral characteristics of cross-sectional emissions from a partially premixed methane/air and propane/air flames have been investigated. An optical train with a two-axis scanning mirror system was used to record line-of-sight emission spectra from 354nm to 618nm, and inversion technique was adapted to obtain cross-sectional emission spectra. By analyzing the reconstructed emission spectra, cross-sectional intensities of CH and $C_2$ radicals were separated from the background emissions. The blue flame edge and yellow flame edge were also obtained by image processing technique for edge detection with color photograph of flame. These edges were compared with radial distributions of CH, $C_2$ radicals and background emissions. The CH radicals were observed at blue flame edge. The background emissions were generated by soot precursor at upstream of flame and by soot at downstream of flame. The $C_2$ radicals in propane/air flame were observed more than those in methane/air flame.

• Journal of Chest Surgery
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• 제32권4호
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• pp.388-393
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• 1999

배경: 식도암 치료에 있어서 수술전 병기 결정은 매우 중요하다. 특히 절제 가능성을 알기 위해서 흉부 단층 촬영과 내시경등 여러 방법을 사용하고 있지만 어떤 검사도 충분한 정보를 제공하지 못하고 있다. 이에 식도암 환자의 병기 결정에 있어서 양전자방출단층촬영의 역할을 알아보고자 연구를 실시하였다. 대상 및 방법: 1997년 1월부터 10월까지 내시경을 통한 조직 검사상 식도 편평 상피암으로 확진된 20명(남 19명, 여 1명, 평균연령 61세)의 환자에서 림프절절제를 포함한 근치적 절제를 시행한 후, 수술전 [F-18]FDG-PET 및 CT 소견과 수술 후 조직 병리 소견을 비교하였다. 결과: 원발 종양 진단에 대한 PET와 CT의 민감도는 90%로 동일하였다. PET와 CT 모두 1 cm 크기의 상피내암종 1예와 T1 병기의 종양 1예에 대하여 위음성을 보였다. 총193개의 절제된 림프절군에 대한 병리 조직 검사 결과를 바탕으로 PET와 CT의 민감도, 특이도, 정확도를 구하였으며 결과는 다음과 같았다.(*$\chi$2 p < 0.005) 민감도** 특이도 정확도* PET 55.6%(30/54) 97.1%(135/139) 85.5%(165/193) CT 13.0%(7/54) 98.6%(137/139) 74.6%(144/193) PET에서 위양성 림프절 전이를 보였던 4명중 1명의 환자는 활동성 폐결핵을 동반한 환자였으며, PET에서 위음성을 보였던 24개의 림프절군중 14개는 감쇠보정을 실시하지 않은 부위에, 5개는 원발 종양과 근접한 부위에 있었다. 결론: PET에서 위양성 림프절 전이를 보였던 4명중 1명의 환자는 활동성 폐결핵을 동반한 환자였으며, PET에서 위음성을 보였던 24개의 림프절군중 14개는 감쇠보정을 실시하지 않은 부위에, 5개는 원발 종양과 근접한 부위에 있었다. 결론: 이상과 같은 결과로부터 [F-18]FDG-PET는 식도암의 림프절 전이 및 병기를 결정하는데 있어서 CT의 결점을 보완할 수 있는 유용한 진단 방법임을 알 수 있었다.

• Journal of Chest Surgery
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• 제36권2호
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• pp.79-85
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• 2003

배경: 흉부 전산화 단층촬영(CT)의 폐암 진단율의 한계로 인하여 최근 폐암에 대한 진단과 병기결정에 양전자단층촬영(PET)이 유정한 것으로 알려져 있다. 이에 우리나라 폐암 환자에서 진단 및 병기 결정에 전산화 단층촬영과 양전자단층촬영의 진단율의 차이점과 유용성을 비교하고자 하였다. 대상 및 방법: 1998년 6월부터 1999년 12월까지 흥부 X-선 촬영과 CT에서 폐암이 의심퇴거나 진단된 55명에서, 차 장기에서 폐로 전이된 9명과 폐암수술후 재발된 5명을 제외한 41명을 대상으로 수술전 CT와 PET 소견과 종격동경이나 개흉술로 확진된 조직병리 소견을 비교하였다. 결과: 41명 대상환자 중 폐종양의 조직학적 진단은 악성병변이 35례 (편평세포암 19례, 선암 14례, 선편평세포암 2례)있고, 양성병변은 6례였다. 폐종양의 악성여부에 대한 CT와 PET 두가지 검사의 민감도, 특이도, 정확도는 같았으며 각각 100%, 50%, 92.7%였다. 최종적인 병리적 림프 절군 병기는 N0-Nl 31례, N2 8례, N3 2례 였다. 림프절군 병기가 일치하는 경우는 CT가 31례, PET가 28례였고, CT와 PET의 각간 6례에서 병리학적 림프절 병기보나 낮게 평가되었고, CT의 4례, PET의 7례에서 병기보다 높게 평가되었다. 조직검사가 가능했던 108개비 종격동 림프절군 중 18개 림프절군에서 악성으고 나왔고, 종격동 림프절군 침범여부에 대한 CT와 PET의 민감도, 특이도, 정확도는 각각 39.8%, 93.3%. 84.3%와 61.1%, 90.0%, 85.2% 였다. 종격동 림프절군 대한 CT와 PET 검사를 종합하여 같이 분석하였을 때 민감도 77.8%, 특이도 93.3%, 정확도 90.7%이었다. 결론: 폐종양과 림프절군의 병기 설정에 있어 PET검사는 CT와 비교하여 비슷한 유용성이 있는 건사로 사료되며, CT와 PET두 검사를 같이 시행하여 검토할 때 정착도를 높일 수 있다고 여겨진다.

• Journal of Yeungnam Medical Science
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• 제40권4호
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• pp.343-351
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• 2023

Diabetic foot is one of the most devastating consequences of diabetes, resulting in amputation and possibly death. Therefore, early detection and vigorous treatment of infections in patients with diabetic foot are critical. This review seeks to provide guidelines for the therapy and rehabilitation of patients with moderate-to-severe diabetic foot. If a diabetic foot infection is suspected, bacterial cultures should be initially obtained. Numerous imaging studies can be used to identify diabetic foot, and recent research has shown that white blood cell single-photon emission computed tomography/computed tomography has comparable diagnostic specificity and sensitivity to magnetic resonance imaging. Surgery is performed when a diabetic foot ulcer is deep and is accompanied by bone and soft tissue infections. Patients should be taught preoperative rehabilitation before undergoing stressful surgery. During surgical procedures, it is critical to remove all necrotic tissue and drain the inflammatory area. It is critical to treat wounds with suitable dressings after surgery. Wet dressings promote the formation of granulation tissues and new blood vessels. Walking should begin as soon as the patient's general condition allows it, regardless of the wound status or prior walking capacity. Adequate treatment of comorbidities, including hypertension and dyslipidemia, and smoking cessation are necessary. Additionally, broad-spectrum antibiotics are required to treat diabetic foot infections.

• 대한임상검사과학회지
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• 제37권2호
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• pp.123-128
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• 2005

Magnetoencephalography (MEG) is the measurement of the magnetic fields produced by electrical activity in the brain, usually conducted externally, using extremely sensitive devices such as Superconducting Quantum Interference Device (SQUID). MEG needs complex and expensive measurement settings. Because the magnetic signals emitted by the brain are on the order of a few femtoteslas (1 fT = 10-15T), shielding from external magnetic signals, including the Earth's magnetic field, is necessary. An appropriate magnetically shielded room is very expensive, and constitutes the bulk of the expense of an MEG system. MEG is a relatively new technique that promises good spatial resolution and extremely high temporal resolution, thus complementing other brain activity measurement techniques such as electroencephalography (EEG), positron emission tomography (PET), single-photon emission computed tomography (SPECT) and functional magnetic resonance imaging (fMRI). MEG combines functional information from magnetic field recordings with structural information from MRI. The clinical uses of MEG are in detecting and localizing epileptic form spiking activity in patients with epilepsy, and in localizing eloquent cortex for surgical planning in patients with brain tumors. Magnetoencephalography may be used alone or together with electroencephalography, for the measurement of spontaneous or evoked activity, and for research or clinical purposes.

• Clinical and Experimental Pediatrics
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• 제63권3호
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• pp.88-95
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• 2020

Accurate localization of the seizure onset zone is important for better seizure outcomes and preventing deficits following epilepsy surgery. Recent advances in neuroimaging techniques have increased our understanding of the underlying etiology and improved our ability to noninvasively identify the seizure onset zone. Using epilepsy-specific magnetic resonance imaging (MRI) protocols, structural MRI allows better detection of the seizure onset zone, particularly when it is interpreted by experienced neuroradiologists. Ultra-high-field imaging and postprocessing analysis with automated machine learning algorithms can detect subtle structural abnormalities in MRI-negative patients. Tractography derived from diffusion tensor imaging can delineate white matter connections associated with epilepsy or eloquent function, thus, preventing deficits after epilepsy surgery. Arterial spin-labeling perfusion MRI, simultaneous electroencephalography (EEG)-functional MRI (fMRI), and magnetoencephalography (MEG) are noinvasive imaging modalities that can be used to localize the epileptogenic foci and assist in planning epilepsy surgery with positron emission tomography, ictal single-photon emission computed tomography, and intracranial EEG monitoring. MEG and fMRI can localize and lateralize the area of the cortex that is essential for language, motor, and memory function and identify its relationship with planned surgical resection sites to reduce the risk of neurological impairments. These advanced structural and functional imaging modalities can be combined with postprocessing methods to better understand the epileptic network and obtain valuable clinical information for predicting long-term outcomes in pediatric epilepsy.

• 대한핵의학회지
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• 제37권1호
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• pp.24-33
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• 2003

Finding epileptogenic zone is the most important step for the successful epilepsy surgery. F-18 fluorodeoxyglucose positron emission tomography (FDG-PET) and single photon emission computed tomography (SPECT) can be used in the localization of epileptogenic foci. In medial temporal lobe epilepsy, the diagnostic sensitivity of FDG-PET and ictal SPECT is excellent. However, detection of hippocampal sclerosis by MRI is so certain that use of FDG-PET and ictal SPECT in medial temporal lobe epilepsy is limited for some occasions. In neocortical epilepsy, the sensitivities of FDG-PET or ictal SPECT are fair. However, FDG-PET and ictal SPECT can have a crucial role in the localization of epileptogenic foci for non-lesional neocortical epilepsy. Interpretation of FDG-PET has been recently advanced by voxel-based analysis and automatic volume of interest analysis based on a population template. Both analytical methods can aid the objective diagnosis of epileptogenic foci. Ictal SPECT was analyzed using subtraction methods and voxel-based analysis. Rapidity of injection of tracers, ictal EEG findings during injection of tracer, and repeated ictal SPECT were important technical issues of ictal SPECT. SPECT can also be used in the evaluation of validity of Wada test.

• Journal of Yeungnam Medical Science
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• 제26권1호
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• pp.15-23
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• 2009

Constant technological developments in coronary artery disease have contributed to the assessment of both the presence of coronary stenosis and its hemodynamic consequences. Hence, noninvasive imaging helps guide therapeutic decisions by providing complementary information on coronary morphology and on myocardial perfusion and metabolism. This can he done using single photon emission computed tomography (SPECT) or positron emission tomography (PET) and multidetector CT (MDCT). Advances in image-processing software and the advent of SPECT/CT and PET/CT have paved the way for the combination of image datasets from different modalities, giving rise to hybrid imaging. Three dimensional cardiac hybrid imaging helped to confirm hemodynamic significance in many lesions, add new lesions such as left main coronay artery disease, exclude equivocal defects, correct the corresponding arteries to their allocated defects and identify culprit segment. Cardiac hybrid imaging avoids the mental integration of functional and morphologic images and facilitates a comprehensive interpretation of coronaty lesions and their pathophysiologic adequacy by three dimensional display of fused images, and allows the best evaluation of myocardial territories and the coronary-artery branches that serve each territory. This integration of functional and morphological information were feasible to intuitively convincing and might facilitate development of a comprehensive non-invasive assessment of coronary artery disease.

• Journal of Radiation Protection and Research
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• 제49권1호
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• pp.1-18
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• 2024

Exponential growth has been observed in nuclear medicine procedures worldwide in the past decades. The considerable increase is attributed to the advance of positron emission tomography and single photon emission computed tomography, as well as the introduction of new radiopharmaceuticals. Although nuclear medicine procedures provide undisputable diagnostic and therapeutic benefits to patients, the substantial increase in radiation exposure to nuclear medicine patients raises concerns about potential adverse health effects and calls for the urgent need to monitor exposure levels. In the current article, model-based internal dosimetry methods were reviewed, focusing on Medical Internal Radiation Dose (MIRD) formalism, biokinetic data, human anatomy models (stylized, voxel, and hybrid computational human phantoms), and energy spectrum data of radionuclides. Key results from many articles on nuclear medicine dosimetry and comparisons of dosimetry quantities based on different types of human anatomy models were summarized. Key characteristics of seven model-based dose calculation tools were tabulated and discussed, including dose quantities, computational human phantoms used for dose calculations, decay data for radionuclides, biokinetic data, and user interface. Lastly, future research needs in nuclear medicine dosimetry were discussed. Model-based internal dosimetry methods were reviewed focusing on MIRD formalism, biokinetic data, human anatomy models, and energy spectrum data of radionuclides. Future research should focus on updating biokinetic data, revising energy transfer quantities for alimentary and gastrointestinal tracts, accounting for body size in nuclear medicine dosimetry, and recalculating dose coefficients based on the latest biokinetic and energy transfer data.

• 한국정보처리학회논문지
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• 제5권12호
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• pp.3275-3284
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• 1998

본 논문에서는 각종 단층 촬영 의료영상 장비로 촬영한 2차원 단면화상 데이터들을 차원 재구성 알고리즘을 사용하여 3차원 영상으로 재구성한 다음, 웹 서버의 데이터베이스에 저장하고 관리하며, 인터넷 가상현실 표준언어인 VRML(Virtual Reality Modeling Language)로 표현된 3차원 의료영상을 비롯한 각종 의료영상 정보를 웹브라우저를 사용하여 검색해 볼 수 있는 의료영상정보시스템(Medical Image Information System)에 관하여 기술한다. 본 연구를 통하여 개발한 의료영상정보시스템에서는 단층 촬영된 2차원 단면화상을 처리한 다음, 3차원 의료 영상을 생성하기 위하여 표면기반 랜더링 방법(Surface-based Rendering Method)을 사용하였다. 인터넷을 통하여 전송되는 영상파일의 크기를 줄이기 위하여 삼각형 매쉬(Triangle Meshes)을 이루는 다각형의 개수를 줄이는 알고리즘을 사용하며, 3차원 의료영상 데이터의 크기를 약 50%이상 줄일 수 있다. 아울러, 3차원 영상 데이터 파일을 압축을 하게 되면 파일의 크기를 80%이상 줄일 수 가 있으므로 웹상에서 신속하게 3차원 의료영상 데이터를 검색할 수 있고, 의료영상을 VRML을 사용하여 표현하므로 고성능의 그래픽 카드가 없는 일반 PC에서도 인터넷을 통하여 디스플레이 할 수 있다. 또한, CGI(Common Gateway Interface)방식을 사용하여 서버의 데이터베이스에 저장되어 있는 CT(Computerized Tomography), MRI(Magnetic Resonance Imaging), PET(Positron Emission Tomography), SPECT(Single Photon Emission Computed Tomography)등의 단층 촬영 장비로 촬영한 다양한 종류의 디지털 의료영상을 사용자에게 의료영상정보시스템을 통하여 2차원 단면화상 또는 3차원 영상으로 표현하여 보여주고, 환자에 관한 각종 정보와 진단정보 등을 신속하게 제공한다. 본 논문에서 제안하는 의료영상정보시스템은 초고속 정보통신 망을 통하여 원격의료시스템을 구축하는데 활용될 수 있을 것이다.