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Deep-Learning-Based Molecular Imaging Biomarkers: Toward Data-Driven Theranostics
최홍윤 한국의학물리학회 2019 의학물리 Vol.30 No.2
Deep learning has been applied to various medical data. In particular, current deep learning models exhibit remarkable performance at specific tasks, sometimes offering higher accuracy than that of experts for discriminating specific diseases from medical images. The current status of deep learning applications to molecular imaging can be divided into a few subtypes in terms of their purposes: differential diagnostic classification, enhancement of image acquisition, and image-based quantification. As functional and pathophysiologic information is key to molecular imaging, this review will emphasize the need for accurate biomarker acquisition by deep learning in molecular imaging. Furthermore, this review addresses practical issues that include clinical validation, data distribution, labeling issues, and harmonization to achieve clinically feasible deep learning models. Eventually, deep learning will enhance the role of theranostics, which aims at precision targeting of pathophysiology by maximizing molecular imaging functional information.
최홍윤,이원우,소영,하승균,변석수,김상은 대한핵의학회 2014 핵의학 분자영상 Vol.48 No.4
P u r p o s e : We i n v e s t i g a t ed Tc - 9 9mhydroxymethylene diphosphonate (HMDP) scintigraphy findingsin renal tumor patients from the perspective of postoperativerenal dysfunction following nephron-sparing surgery(NSS). Methods: Forty-three renal tumor patients (M:F =28:15, age 53.9±12.5 years) who had undergone Tc-99mHMDP scintigraphy after NSS were enrolled. The patientswere divided into HMDP+ or HMDP− groups by visual assessment,and the asymmetric index (ASI) was calculatedusing a region-of-interest analysis. In 16 patients, the totaland split glomerular filtration rate (GFR) was assessed usingTc-99m diethylenetriaminepentaacetic acid (DTPA) scintigraphyat baseline and at 3 and 6months post-NSS. Results: HighTc-99m HMDP uptake was observed in the operated kidneys,but this did not persist later than 7 days post-NSS. Split GFRof the operated kidneys at baseline (58.5±9.3 ml/min) wassignificantly reduced at 6 months post-NSS (40.1±5.9 ml/min, p<0.001) in only those who showed intense uptake ofTc-99m HMDP. Declines in both total GFR (p=0.010 and p=0.002 for 3 and 6 months, respectively) and split GFR of theoperated kidneys (p<0.001 and p<0.001 for 3 and 6 months,respectively) were clearly evidenced at 3 and 6 months post-NSS only in patients with high Tc-99m HMDP in the operatedkidneys. The ASI was negatively correlated with %change inthe split GFR of these operated kidneys at 6 months post-NSS(rho =−0.578, p=0.0304). Conclusions: Tc-99m HMDP uptakewithin 1 week following NSS is a surrogate marker ofGFR impairment over 6 months post-NSS.
최홍윤,유민영,천기정,강건욱,정준기,이동수 대한핵의학회 2013 핵의학 분자영상 Vol.47 No.3
Purpose Basal/acetazolamide stress 99mTc-HMPAO singlephoton emission computed tomography (SPECT) has been widely used for evaluation of hemodynamics; however,qualitative and subjective visual assessment of cerebrovascular reserve (CVR) has been performed in clinical settings. The aim of this study was to generate parametric CVR images and evaluate its feasibility of quantification. Methods Basal/acetazolamide stress 99mTc-HMPAO SPECT data from 17 patients who underwent bypass surgery or percutaneous transluminal angioplasty were used. Spatial normalization was performed and parametric CVR images were generated using relative CVR (rCVR) of each voxel proportional to CVR of the whole brain. Binary parametric maps to show area of relatively reduced CVR were generated also using threshold of rCVR < 90 %. We calculated rCVR of internal carotid artery (ICA) using the parametric CVR images and probabilistic maps for ICA territory. Pre- and postprocedural parametric CVR images were obtained and quantitative rCVRs were compared. The rCVRs were evaluated according to visual grades for regional decreased CVR. Results Postprocedural rCVR obtained from parametric CVR images increased significantly from preprocedural rCVR. The rCVR was significantly correlated with visual grades of reduced CVR for each side of ICA territories. Conclusions We generated parametric CVR images for basal/acetazolamide stress 99mTc-HMPAO SPECT. As a quantitative measurement, rCVR obtained from the parametric image was feasibly assessed hemodynamic abnormalities with preserved anatomical information.
Radiomics in Oncological PET/CT: a Methodological Overview
하승균,최홍윤,팽진철,천기정 대한핵의학회 2019 핵의학 분자영상 Vol.53 No.1
Radiomics is a medical imaging analysis approach based on computer-vision. Metabolic radiomics in particular analyses the spatial distribution patterns of molecular metabolism on PET images. Measuring intratumoral heterogeneity via image is one of the main targets of radiomics research, and it aims to build a image-based model for better patient management. The workflow of radiomics using texture analysis follows these steps: 1) imaging (image acquisition and reconstruction); 2) preprocessing (segmentation & quantization); 3) quantification (texture matrix design & texture feature extraction); and 4) analysis (statistics and/or machine learning). The parameters or conditions at each of these steps are effect on the results. In statistical testing or modeling, problems such as multiple comparisons, dependence on other variables, and high dimensionality of small sample size data should be considered. Standardization of methodology and harmonization of image quality are one of the most important challenges with radiomics methodology. Even though there are current issues in radiomics methodology, it is expected that radiomics will be clinically useful in personalized medicine for oncology.
하시모토 갑상선염이 있는 환자에서의 갑상선 전이암의 진단: 유방암 및 폐암의 전이 증례
임승균,최홍윤,임석아,조선욱 대한갑상선학회 2020 International Journal of Thyroidology Vol.13 No.2
Metastatic disease involving the thyroid gland is uncommon. Thyroid metastases has been previously describedfrom several primary cancers of lung, breast, and kidney. Because of the lower incidence and ambiguous clinicalsignificance, it is not easy to consider thyroid metastasis and decide the optimal time for performing diagnosticexamination. Here, we reported two cases of metastatic diseases of thyroid in patients who had underlyingHashimoto’s thyroiditis: a 39-year-old woman who had thyroid metastasis of breast cancer with underlyingHashimoto’s thyroiditis, and a 44-year-old woman with metastatic lung cancer.
Repletion Mechanism of Catecholamine in PC12 Cells
Choi, Kyung Hee,Choi, Hong Yun,Kim, Mie Young 中央大學校 遺傳工學硏究所 1991 遺傳工學硏究論集 Vol.4 No.1
본 연구에서는 PC12 세포에서 카테콜아민을 방출하는 자극이 고갈된 카테콜아민을 보충시키는 자극으로 작용하는지와 보충에 관련된 기작을 조사하기 위하여, Nicotinic 수용체의 효능제인 Nicotine을 처리하여 TH mRNA수준과 TH효소 활성도를 조사하였다. Nicotine을 단시간 (5, 15, 30분) 처리한 경우 TH mRNA 수준에는 변함이 없었으나 TH효소 활성도는 급격히 증가하여 5분만에 대조군에 비해 295%를 나타내었다. 이상의 결과는 Nicotine에 의해 부분적으로 고갈된 카테콜아민을 보충시키기 위해서는 이미 존재하고 있던 TH 단백질이 변형됨으로써 촉매 활성도가 증가됨을 나타내고 있다. The purpose of the present study was evaluate the functional role of nicotinic receptors in the secretion of catecholamine and to determine whether a signal for the released catecholamine might also function as the signal for compensatory catecholamine repletion by enhancing the biosynthesis of the released catecholamines in rat adrenal pheochromocytoma 12 cells. We examined the mRNA level of tyrosine hydroxylase(TH) gene and activity of TH after treatment of nicotinic receptor agonist to PC12 cells. During the short time treatment (up to 30 min) no significant changes in mRNA level was observed. However, TH enzyme activity rose rapidly in 5 min after treatment of nicotine, reaching a peak corresponding to 295% of the control level. These data suggest that the partially depleted catecholamaine might be compensated by the acute activation of pre-existing TH protein immediately after catecholamine release.