• 대한의용생체공학회:의공학회지
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• 제25권3호
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• pp.183-188
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• 2004

Magnetic resonance current density imaging (MRCDI) is a useful method for measuring electrical current density distribution inside an object. To avoid object rotations during the conventional MRCDI scans, we have reconstructed current density component images by applying a spatial filter to the magnetic field data measured both inside and outside the object. To measure the magnetic field outside the object with MRI, we immersed the object in a water tank. To evaluate accuracy of the current density imaging, we have made a conductivity phantom with a corresponding finite element method model. We have compared the experimentally obtained current density images with the ones calculated by the finite element method. The average errors of the reconstructed current density images were 6.6 ∼ 45.4 ％ when the injected currents were 1 ∼ 24 mA. We expect that the current density component imaging technique can be used in diverse biomedical applications such as electrical therapy system developments and biological electrical safety analysis.

• Investigative Magnetic Resonance Imaging
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• 제20권2호
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• pp.114-119
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• 2016

We report a case of vegetation in a 4-year-old female with infective endocarditis, diagnosed by late gadolinium-enhanced (LGE) cardiovascular magnetic resonance (CMR) imaging. The patient had a history of primary closure for ventricular septal defect and presented with mild febrile sensation. No remarkable clinical symptoms or laboratory findings were noted; however, transthoracic echocardiography demonstrated a 14 mm highly mobile homogeneous mass in the right ventricle. On LGE CMR imaging, the mass showed marginal rim enhancement, which suggested the diagnosis of vegetation rather than thrombus. The extracellular volume fraction (${\geq}42%$) of the lesion was higher than that of normal myocardium. Based on the patient's clinical history of congenital heart disease and pathologic confirmation of the lesion, a diagnosis of infective endocarditis with vegetation was made.

• 한국임상수의학회지
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• 제36권4호
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• pp.207-211
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• 2019

This study was performed to compare the radiographic and echocardiographic features of cardiovascular changes between small and large dogs with heartworm diseases. Total of 49 dogs from two institutions were included in this study. The dogs were diagnosed with heartworm infestation and underwent thoracic and echocardiography. On thoracic radiographs, vertebral heart scale, reverse D shape, main pulmonary artery dilation, peripheral pulmonary artery dilation, and evidence of right heart failure were evaluated. On echocardiographs, visibility of worms, main pulmonary artery to aortic root (MPA/Ao) ratio, right to left ventricular basal diameter (RVD/LVD) ratio, and pulmonary hypertension were evaluated and analyzed between small and large dogs. The proportion of reverse D shape of the heart and accuracy for right ventricular hypertrophy in small dogs were lower than those of the large dogs. For echocardiographic parameter, the MPA/Ao and RVD/LVD ratio in the small dogs were significantly lower than those of the large dogs. As the results, thoracic radiography have a tendency to underestimate the severity of HWD in small dogs and should be used with echocardiography.

• 대한디지털의료영상학회논문지
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• 제5권1호
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• pp.32-44
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• 2002

The role of radiology department has been greatly increased in the past few years as the technology in the medical imaging devices improved and the introduction of PACS (Picture Archiving and Communications System) to the conventional film-based diagnostic structure is a truly remarkable factor to the medical history. In addition, the value of using digital information in medical imaging is highly expected to grow as the technology over the computer and the network improves. However, the current medical practice, using PACS is somewhat limited compared to the film-based conventional one due to a poor image quality. The image quality is the most important and inevitable factor in the PACS environment and it is one of the most necessary steps to more wide practice of digital imaging. The existing image quality control tools are limited in controlling images produced from the medical modalities, because they cannot display the real image changing status. Thus, the image quality is distorted and the ability to diagnosis becomes hindered compared to the one of the film-based practice. In addition, the workflow of the radiologist greatly increases; as every doctor has to perform his or her own image quality control every time they view images produced from the medical modalities. To resolve these kinds of problems and enhance current medical practice under the PACS environment, we have developed a program to display a better image quality by using the ROI optical density of the existing gray level values. When the LUT is used properly, small detailed regions, which cannot be seen by using the existing image quality controls are easily displayed and thus, greatly improves digital medical practice. The purpose of this study is to provide an easier medical practice to physicians, by applying the technology of converting the H-D curves of the analog film screen to the digital imaging technology and to preset image quality control values to each exposed body part, modality and group of physicians for a better and easier medical practice. We have asked to 5 well known professional physicians to compare image quality of the same set of exam by using the two different methods: existing image quality control and the LUT technology. As the result, the LUT technology was enormously favored over the existing image quality control method. All the physicians have pointed out the far more superiority of the LUT over the existing image quality control method and highly praised its ability to display small detailed regions, which cannot be displayed by existing image quality control tools. Two physicians expressed the necessity of presetting the LUT values for each exposed body part. Overall, the LUT technology yielded a great interest among the physicians and highly praised for its ability to overcome currently embedded problems of PACS. We strongly believe that the LUT technology can enhance the current medical practice and open a new beginning in the future medical imaging.

• Korean Journal of Radiology
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• 제22권2호
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• pp.213-224
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• 2021

Objective: Clinical outcomes of patients who undergo transarterial chemoembolization (TACE) for single small hepatocellular carcinoma (HCC) are not consistent, and may differ based on certain imaging findings. This retrospective study was aimed at determining the efficacy of pre-TACE CT or MR imaging findings in predicting survival outcomes in patients with small HCC upon being treated with TACE. Besides, the study proposed to build a risk prediction model for these patients. Materials and Methods: Altogether, 750 patients with functionally good hepatic reserve who received TACE as the first-line treatment for single small HCC between 2004 and 2014 were included in the study. These patients were randomly assigned into training (n = 525) and validation (n = 225) sets. Results: According to the results of a multivariable Cox analysis, three pre-TACE imaging findings (tumor margin, tumor location, enhancement pattern) and two clinical factors (age, serum albumin level) were selected and scored to create predictive models for overall, local tumor progression (LTP)-free, and progression-free survival in the training set. The median overall survival time in the validation set were 137.5 months, 76.1 months, and 44.0 months for low-, intermediate-, and high-risk groups, respectively (p < 0.001). Time-dependent receiver operating characteristic curves of the predictive models for overall, LTP-free, and progression-free survival applied to the validation cohort showed acceptable areas under the curve values (0.734, 0.802, and 0.775 for overall survival; 0.738, 0.789, and 0.791 for LTP-free survival; and 0.671, 0.733, and 0.694 for progression-free survival at 3, 5, and 10 years, respectively). Conclusion: Pre-TACE CT or MR imaging findings could predict survival outcomes in patients with small HCC upon treatment with TACE. Our predictive models including three imaging predictors could be helpful in prognostication, identification, and selection of suitable candidates for TACE in patients with single small HCC.

• 대한방사성의약품학회지
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• 제1권1호
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• pp.23-30
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• 2015

Radioisotopes emitting low-range highly ionizing radiation such as ${\beta}$-particles are of increasing significance in internal radiotherapy. Among the ${\beta}$-particle emitting radioisotopes, $^{67}Cu$ is an attractive radioisotope for various nuclear medicine applications due to its medium energy ${\beta}$-particle, gamma emissions, and 61.83-hour half-life, which can also be used with $^{64}Cu$ for PET imaging. The production and application of the ${\beta}$-emitting radioisotope $^{67}Cu$ for therapeutic radiopharmaceutical are outlined, and different production routes are discussed. A survey of copper chelators used for antibody labeling is provided. It has been produced via proton, alpha, neutron, and gamma irradiations followed by solvent extraction, ion exchange, electrodeposition. Clinical studies using $^{67}Cu$-labelled antibodies in lymphoma, colon carcinoma and bladder cancer patients are reviewed. Widespread use of this isotope for clinical studies and preliminary treatments has been limited by unreliable supplies, cost, and difficulty in obtaining therapeutic quantities.

• 한국방사선학회논문지
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• 제17권4호
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• pp.565-572
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• 2023

본 연구에서는 국내 공공 부문에서 실시하고 있는 의료기관 평가 중 영상검사와 관련된 현황을 살펴보고 개선 방향을 제시하고자 하였다. 의료기관 평가 중 영상검사와 관련된 주요 평가는 의료기관 인증평가와 영상검사 적정성 평가가 있으며, 의료기관 인증평가에서는 영상검사 운영과정, 정확한 결과 제공, 안전관리 절차 준수 등을 평가하고 있다. 영상검사 적정성 평가에서는 인력, 장비와 관련된 구조 지표, 환자평가 실시율, 피폭 저감 프로그램 등이 포함되어 있었다. 하지만 좀 더 안전하고 질 높은 영상검사를 위해서는 의료기관의 인증평가 참여율을 높이는 방안 마련이 필요하며, 영상검사 적정성 평가의 인력지표 개선과 인센티브 지급에 대한 고려도 필요하다. 마지막으로 국가 차원의 방사선 노출 통합관리도 함께 병행되어야 할 것이다.

• 대한방사선협회지
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• 제30권1호
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• pp.58-62
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• 2004

The purpose of this study was to determine the factors influencing on the size of Radiofrequency ablation using an internally cooled needle electrodes in cattle liver. Ablation procedures involved the use of cool-tip RF system generator and internally coo

• 한국임상수의학회:학술대회논문집
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• 한국임상수의학회 2008년도 추계학술대회
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• pp.179-179
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• 2008

• 대한방사성의약품학회지
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• 제2권2호
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• pp.108-112
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• 2016

Molecular imaging with the radiolabeled RGD peptides for ${\alpha}_v{\beta}_3$ integrin has been an increasing interest for tumor diagnosis and the treatment monitoring. Recently, $^{64}Cu$-NODAGA-gluco-E[c(RGDfK)]$_2$ was developed for quantification of ${\alpha}_v{\beta}_3$ integrin and its biological properties was elucidated. To better understand the molecular process in vivo, we performed the kinetic analysis for the $^{64}Cu$-NODAGA-gluco-E[c(RGDfK)]$_2$. After preparation of a radiotracer, dynamic PET images were obtained in the U87MG xenograft mice for 60 min (n = 6). Binding potential values were estimated from the 3-tissue compartment model, reference Logan and simplified reference tissue model. In the early time frame (0-20 min), the liver, kidney, intestine, urinary bladder and tumor were visualized but these uptakes were diminished as time went by. The tumors showed a good contrast at 40 min after administration. $^{64}Cu$-NODAGA-gluco-E[c(RGDfK)]$_2$ showed the 2-fold uptake in the tumor compared with that in the muscle. The parametric maps for binding values also provide the higher tumor-to-background contrast than the static images. A binding value obtained from the 3-tissue compartment model was comparable to other modeling methods. From these results, we conclude that $^{64}Cu$-NODAGA-gluco-E[c(RGDfK)]$_2$ may be a promising PET radiotracer for the evaluation of angiogenesis.