• 대한핵의학회지
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• 제38권2호
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• pp.198-204
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• 2004

Tumor cell proliferation is considered to be a useful prognostic indicator of tumor aggressiveness and tumor response to therapy but in vitro measurement of individual proliferation is complex and tedious work. PET imaging provides a noninvasive approach to measure tumor growth rate in situ. Early approaches have used $^{18}F$-FDG or methionine to monitor proliferation status. These 2 tracers detect changes in glucose and amino acid metabolism, respectively, and therefore provide only an indirect measure of proliferation status. More recent studies have focused on DNA synthesis itself as a marker of cell proliferation. Cell lines and tissues with a high proliferation rate require high rates of DNA synthesis. $[^{11}C]Thymidine$ was the first radiotracer for noninvasive imaging of tumor proliferation. The short half-life of $^{11}C$ and rapid metabolism of $[^{11}C]Thymidine$ in vivo make the radiotracer less suitable for routing use. Halogenated thymidine analogs such as 5-iodo-2-deoxyuridine (IUdR) can be successfully used as cell proliferation markers for in vitro studies because these compounds are rapidly incorporated into newly synthesized DNA. IUdR has been evaluated as a potential in vivo tracer in nuclear medicing but the image qualify and the calculation of proliferation rates are impaired by its rapid in vivo degradation. Hence, the thymidine analog $3'-deoxy-3'-^{18}F-fluorothymidine$ (FLT) was recently introduced as a stable proliferation marker with a suitable nuclide half-life and stable in vivo. $[^{18}F]FLT$ is phosphorylated to 3-fluorothymidine monophosphate by thymidine kinase 1 and reflects thymidine kinase 1 activity in proliferating cell. $[^{18}F]FLT$ PET is feasible in clincal use and well correlates with cellular proliferation. Choline is a precursor for the biosynthesis of phospholipids (in particular, phosphatidylcholine), which is the essential component of all eukaryotic cell membranes and $[^{11}C]choline$, which is a new marker for cellular proliferation.

• 한국멀티미디어학회논문지
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• 제9권12호
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• pp.1580-1587
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• 2006

The term molecular imaging can be broadly defined as the in vivo characterization and measurement of biologic processes at the cellular and molecular level. Optical imaging that has highly reproducibility and repetition used in molecular imaging research. In the bioluminescence imaging, animals carrying the luciferase gene are imaged with a cooled CCD(Charge-Coupled Device) camera to pick up the small number of photons transmitted through tissues. Molecular imaging analysis will allow us to observe the incipience and progression of the disease. But hardware device for molecular imaging and software for molecular image analysis were dependent on imports. In this paper, we suggest image processing methods and designed software for bioluminescence signal analysis. And we demonstrated high correlation(r=0.99) between our software's photon counts and commercial software's photon counts. ROI function and processing functions were accomplished without error. This study have the importance of the development software for bioluminescence image processing and analysis. And this study built the foundations for creative development of analysis methods. We expected this study lead the development of image technology.

• 대한방사성의약품학회지
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• 제4권1호
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• pp.36-42
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• 2018

Molecular imaging refers to detect the biochemical process in living organisms at the cellular and molecular levels and to quantify them. Due to several advantages of nanomaterials, various molecular images using nanomaterials are being tried. Attempts have been made to combine nanoparticles, known as micro- or nanosized nanomaterials, with radioactive isotopes for molecular imaging probe. The radiolabeled nanoparticles will expend the molecular imaging due to nanoparticle's size-dependent nature. In particular, iron oxide nanoparticles can be used for magnetic resonance imaging, can be adjusted in size, easily functionalized, and biocompatible, making it a very good platform for molecular imaging. In addition, iron oxide nanoparticles may be the best example for a new approach to molecular imaging techniques. In this paper, we introduce various methods for preparation of iron oxide nanoparticle combined with radioisotope starting from various synthesis methods of iron oxide nanoparticles to utilize iron oxide nanoparticles as a platform for molecular imaging through radioactive labeling.

• 대한핵의학회지
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• 제38권2호
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• pp.115-120
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• 2004

Molecular imaging is a rapidly growing field due to the advances in molecular biology and imaging technologies. With the introduction of imaging reporter genes into the cell, diverse cellular processes can be monitored, quantified and imaged non-invasively in vivo. These precesses include the gene expression, protein-protein interactions, signal transduction pathways, and monitoring of cells such as cancer cells, immune cells, and stem cells. In the near future, molecular imaging analysis will allow us to observe the incipience and progression of the disease. These will make us easier to give a diagnosis in the early stage of intractable diseases such as canter, neuro-degenerative disease, and immunological disorders. Additionally, molecular imaging method will be a valuable tool for the real-time evaluation of cells in molecular biology and the basic biological studies. As newer and more powerful molecular imaging tools become available, it will be necessary to corporate clinicians, molecular biologists and biochemists for the planning, interpretation, and application of these techniques to their fullest potential. in order for such a multidisciplinary team to be effective, it is essential that a common understanding of basic biochemical and molecular biologic techniques is achieved. Basic molecular techniques for molecular imaging methods are presented in this paper.

• Molecules and Cells
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• 제43권7호
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• pp.591-599
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• 2020

Complex cell-to-cell communication underlies the basic processes essential for homeostasis in the given tissue architecture. Obtaining quantitative gene-expression of cells in their native context has significantly advanced through single-cell RNA sequencing technologies along with mechanical and enzymatic tissue manipulation. This approach, however, is largely reliant on the physical dissociation of individual cells from the tissue, thus, resulting in a library with unaccounted positional information. To overcome this, positional information can be obtained by integrating imaging and positional barcoding. Collectively, spatial transcriptomics strategies provide tissue architecture-dependent as well as position-dependent cellular functions. This review discusses the current technologies for spatial transcriptomics ranging from the methods combining mechanical dissociation and single-cell RNA sequencing to computational spatial re-mapping.

• Nuclear Medicine and Molecular Imaging
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• 제42권3호
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• pp.185-191
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• 2008

While indirect targeting strategies using reporter-genes are taking center stage in current molecular imaging research, another vital strategy has long involved direct imaging of specific receptors using radiolabeled ligands. Recently, there is renewal of immense interest in this area with particular attention to the epidermal growth factor receptor (EGFR), a transmembrane glycoprotein critically involved in the regulation of many cellular functions and malignancies. Recently, two novel classes of EGFR-targeting anticancer drugs have entered clinical trials with great expectations. These are monoclonal antibodies such as cetuximab that target the extracellular domain, and small molecule tyrosine kinase inhibitors such as gefitinib (lressa) and erlotinib (Tarceva) that target the catalytic domain of the receptor. However, early results have showed disappointing survival benefits, disclosing a major challenge for this therapeutic strategy; namely, the need to identify tumors that are most likely to respond to the agents. To address this important clinical issue, several noninvasive imaging techniques are under investigation including radiolabeled probes based on small molecule tyrosine kinase inhibitors, anti-EGFR antibodies, and EGF peptides. This review describes the current status, limitations, and future prospects in the development of radiotracer methods for EGFR imaging.

• Journal of the Optical Society of Korea
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• 제14권2호
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• pp.77-89
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• 2010

Digital holography (DH) is a potentially disruptive new technology for many areas of imaging science, especially in microscopy and metrology. DH offers a number of significant advantages such as the ability to acquire holograms rapidly, availability of complete amplitude and phase information of the optical field, and versatility of the interferometric and image processing techniques. This article provides a review of the digital holography, with an emphasis on its applications in biomedical microscopy. The quantitative phase microscopy by DH is described including some of the special techniques such as optical phase unwrapping and holography of total internal reflection. Tomographic imaging by digital interference holography (DIH) and related methods is described, as well as its applications in ophthalmic imaging and in biometry. Holographic manipulation and monitoring of cells and cellular components is another exciting new area of research. We discuss some of the current issues, trends, and potentials.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2008년도 추계학술대회A
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• pp.1446-1449
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• 2008

Immune system is composed of multiple cells with distinct functions, and immune responses are orchestrated by complex and dynamic cell-cell interactions. Therefore, each cell behavior and function should be understood under right spatio-temporal context. Studying such complexity and dynamics has been challenging with conventional biological tools. Recent development of new technologies such as state of art imaging instruments and microfabrication techniques compatible with biological systems have provided many exciting opportunities to dissect complex and dynamic immune cell interactions; new microscopy techniques enable us to observe stunning dynamics of immune system in real time. Microfabrication permits us to manipulate microenvironments governing molecular/cellular dynamics of immune cells to study detailed mechanisms of phenomena observed by microscopy. Also, microfabrication can be used to engineer microenvironments optimal for specific imaging techniques. In this presentation, I am going to present an example of how these two techniques can be combined to tackle challenging problems in immunology. Obviously, this strategy can readily be applied to many different fields of biology other than immunology.

• Nuclear Medicine and Molecular Imaging
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• 제41권2호
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• pp.97-101
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• 2007

Correct localization of epileptogenic zone is important for the successful epilepsy surgery. Both ictal perfusion single photon emission computed tomography (SPECT) and interictal F-18 fluorodeoxyglucose positron emission tomography (FDG-PET) can provide useful information in the presurgical localization of intractable partial epilepsy. These imaging modalities have excellent diagnostic sensitivity in medial temporal lobe epilepsy and provide good presurgical information in neocortical epilepsy. Also provide functional information about cellular functions to better understand the neurobiology of epilepsy and to better define the ictal onset zone, symptomatogenic zone, propagation pathways, functional deficit zone and surround inhibition zones. Multimodality imaging and developments in analysis methods of ictal perfusion SPECT and new PET ligand other than FDG help to better define the localization.

• Molecules and Cells
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• 제38권8호
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• pp.741-741
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• 2015