• 한국진공학회:학술대회논문집
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• 한국진공학회 2015년도 제49회 하계 정기학술대회 초록집
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• pp.51.2-51.2
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• 2015

Understanding interfacial phenomena has been one of the main research issues not only in semiconductors but only in life sciences. I have been trying to meet the atomic scale surface and interface analysis challenges from semiconductor industries and furthermore to extend the application scope to biomedical areas. Optical imaing has been most widely and successfully used for biomedical imaging but complementary ion beam imaging techniques based on mass spectrometry and ion scattering can provide more detailed molecular specific and nanoscale information In this presentation, I will review the 27 years history of medium energy ion scattering (MEIS) development at KRISS and DGIST for nanoanalysis. A electrostatic MEIS system constructed at KRISS after the FOM, Netherland design had been successfully applied for the gate oxide analysis and quantitative surface analysis. Recenlty, we developed time-of-flight (TOF) MEIS system, for the first time in the world. With TOF-MEIS, we reported quantitative compositional profiling with single atomic layer resolution for 0.5~3 nm CdSe/ZnS conjugated QDs and ultra shallow junctions and FINFET's of As implanted Si. With this new TOF-MEIS nano analysis technique, details of nano-structured materials could be measured quantitatively. Progresses in TOF-MEIS analysis in various nano & bio technology will be discussed. For last 10 years, I have been trying to develop multimodal nanobio imaging techniques for cardiovascular and brain tissues. Firstly, in atherosclerotic plaque imaging, using, coherent anti-stokes raman scattering (CARS) and time-of-flight secondary ion mass spectrometry (TOF-SIMS) multimodal analysis showed that increased cholesterol palmitate may contribute to the formation of a necrotic core by increasing cell death. Secondly, surface plasmon resonance imaging ellipsometry (SPRIE) was developed for cell biointerface imaging of cell adhesion, migration, and infiltration dynamics for HUVEC, CASMC, and T cells. Thirdly, we developed an ambient mass spectrometric imaging system for live cells and tissues. Preliminary results on mouse brain hippocampus and hypotahlamus will be presented. In conclusions, multimodal optical and mass spectrometric imaging privides overall structural and morphological information with complementary molecular specific information, which can be a useful methodology for biomedical studies. Future challenges in optical and mass spectrometric imaging for new biomedical applications will be discussed.

• Journal of Magnetics
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• 제20권3호
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• pp.308-311
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• 2015

We design a crisscrossed double-layer birdcage (DLBC) coil by modifying the coil geometry of a standard single-layer BC (SLBC) coil to enhance the homogeneity of transmitting magnetic flux density ($B_1{^+}$) along the main magnetic field ($B_0$)-direction for small-animal magnetic resonance imaging (MRI) at 300 MHz. The performance assessment of the crisscrossed DLBC coil is conducted by computational analysis with the finite-difference time domain method (FDTD) and compared with SLBC coil in terms of the $B_1$ and the $B_1{^+}$ distribution. As per the computational calculation studies, the mean value in the two-dimensional $B_1{^+}$ map obtained at the mid-axial slice with the proposed DLBC coil is slightly lower than that obtained with the SLBC coil, but the $B_1{^+}$ value of the DLBC coil in the outermost plane (40 mm away from the central plane) shows improvements of 19.3% and 24.8% over the SLBC coil $B_1{^+}$ value when simulating a spherical phantom and realistic mouse body modeling. These simulation results indicate that, the $B_1{^+}$ homogeneity along the z-direction was improved by using DLBC configuration. Our approach enables $B_1{^+}$ homogeneity improvement along the zdirection, and it can also be applied to ultra-high field (UHF) MRI systems.

• Nuclear Medicine and Molecular Imaging
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• 제43권3호
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• pp.165-173
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• 2009

Nuclear cardiology in Korea is less active, compared to nuclear oncology, but it has been specialized and ramified. Lately, sophisticated nuclear cardiac imaging methods provide more convenience for patients. It is necessary to accurately estimate the recent progress in the imaging devices for nuclear cardiology. Myocardial perfusion imaging is a well established study to evaluate heart function. Myocardial perfusion SPECT and PET have been used for assessment of coronary artery disease with various radiopharmaceuticals. And of late, the development of advanced imaging devices - multi-pinhole technique and high definition imaging technique - and software made the scanning time shorter and expanded the application field. Therefore, it is required to review the nuclear cardiology hardware/software for the clinical practice and research. In this review, the characteristics about recently-developed SPECT/PET and software for nuclear cardiology are described. It is hoped that this information would contribute to improving the activity of nuclear cardiac research in Korea where the research for the fusion imaging combining a and nuclear imaging is drawing more attention.

• Nuclear Medicine and Molecular Imaging
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• 제42권sup1호
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• pp.121-125
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• 2008

$^{18}F-FDG$ PET has a higher diagnostic accuracy than a in initial staging of testicular cancer. In seminoma, it can discriminate residual tumor from necrosis/fibrosis or mature teratoma. $^{18}F-FDG$ PET is also useful for the response evaluation of chemotherapy. However, there's no clinical evidence for the use of $^{18}F-FDG$ PET in the diagnosis and differential diagnosis of testicular cancer.

• Nuclear Medicine and Molecular Imaging
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• 제42권sup1호
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• pp.149-152
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• 2008

Nonmelanomatous skin cancer includes basal cell carcinoma, squamous cell carcinoma, merkel cell carcinoma and dermatofibrosarcoma protuberance. So far, there have been a few reports that $^{18}F-FDG$ PET was useful in the evaluation of metastasis and therapeutic response in nonmelanomatous skin cancer, however, those are very weak evidences. Therefore, further studies on the usefulness of $^{18}F-FDG$ PET in nonmelanomatous skin cancer are required.

• 대한핵의학회지
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• 제38권2호
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• pp.121-130
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• 2004

Molecular imaging visualizes cellular processes at a molecular or genetic level in living subjects, and diverse molecular probes are used for this purpose. Radiolabeling methods as well as radioisotopes are very important in preparation of molecular probes, because they can affect the biodistribution in tissues and the excretion route. In this review, the molecular probes are divided into small organic molecules and macromolecules such as peptides and proteins, and their commonly used radiolabeling methods are described.

• 대한방사성의약품학회지
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• 제6권1호
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• pp.46-52
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• 2020

Radiopharmaceuticals that can be consumed in specific disease site play a key role In order to diagnose and treat the diseases. In addition, radiopharmaceuticals can be used for diagnostic or therapeutic purposes depending on the type of the labeled radioactive isotope. Recently, theragnostic radiopharmaceuticals that can simultaneously diagnose and treat are developed. Therefore, the development of target-specific radiopharmaceuticals is a very important research topic in the field of molecular imaging and therapy. This review paper summarizes the basic considerations for the development of radiopharmaceuticals. For new researchers or students who are now beginning in the field of radiopharmaceuticals, we intend to assist in the development of radiopharmaceuticals by describing the definition of radiopharmaceuticals, the ideal radiopharmaceutical conditions, the considerations for developing new radiopharmaceuticals, the factors affecting the design of radiopharmaceuticals, the requirements of radioisotope labeling reactions, and finally the definition and importance of molar activity in radiopharmaceuticals.

• Biomolecules & Therapeutics
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• 제21권6호
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• pp.423-434
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• 2013

The adoption of oligonucleotide aptamer is well on the rise, serving an ever increasing demand for versatility in biomedical field. Through the SELEX (Systematic Evolution of Ligands by EXponential enrichment), aptamer that can bind to specific target with high affinity and specificity can be obtained. Aptamers are single-stranded nucleic acid molecules that can fold into complex three-dimensional structures, forming binding pockets and clefts for the specific recognition and tight binding of any given molecular target. Recently, aptamers have attracted much attention because they not only have all of the advantages of antibodies, but also have unique merits such as thermal stability, ease of synthesis, reversibility, and little immunogenicity. The advent of novel technologies is revolutionizing aptamer applications. Aptamers can be easily modified by various chemical reactions to introduce functional groups and/or nucleotide extensions. They can also be conjugated to therapeutic molecules such as drugs, drug containing carriers, toxins, or photosensitizers. Here, we discuss new SELEX strategies and stabilization methods as well as applications in drug delivery and molecular imaging.

• 대한방사성의약품학회지
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• 제1권1호
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• pp.15-22
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• 2015

$^{18}F$-labeling reaction of bioactive molecule via click chemistry is widely used to produce $^{18}F$-labeled radiotracer in the field of radiopharmaceutical science and molecular imaging. In particular, bioorthogonal strain-promoted alkyne-azide cycloaddition (SPAAC) reaction has received much attention as an alternative ligation method for radiolabeling bioactive molecules such as peptides, DNA, proteins as well as nanoparticles. Moreover, SPAAC based pretargeting method could provide tumor images successfully on positron emission tomography system using nanoparticle such as mesoporous silica nanoparticles.

• 대한방사성의약품학회지
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• 제6권2호
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• pp.131-138
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• 2020

Fluorine compounds have attracted interest of scientists for immense applications in medicinal chemistry and pharmaceuticals. Recently, photoredox catalysts, both organic-based and metal-based compounds, have been employed in organic synthetic methodology to achieve desirable products due to facile operation and mild reaction condition. Various protocols to prepare fluorination adducts in the presence of photoredox catalysts have been developed from several starting materials with formation of radical scaffolds. In this review, we describe recent advances in the fluorination using light.