• 대한방사성의약품학회지
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• 제2권1호
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• pp.37-42
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• 2016

The translocator protein (TSPO) has attracted scientist's attention for Positron Emission Tomography (PET) imaging due to correlation with brain cancer, stroke, and neurodegeneration. Recently, GE-180, a novel tricyclic derivative has been developed as a new high affinity agent for the TSPO and evaluated to confirm a possibility for the TSPO ligand. In this highlight review, several studies for the novel TSPO radiotracer are described.

• Molecules and Cells
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• 제26권6호
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• pp.530-535
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• 2008

Optical signals based on Raman scattering, coherent anti-Stokes Raman scattering (CARS), and harmonic generation can be used to image biological molecules in living cells without labeling. Both Raman scattering and CARS signals can be used to detect frequencies of molecular vibrations and to obtain the molecular distributions in samples. Second-harmonic optical signals can also be generated in structured arrays of noncentrosymmetric molecules and can be used to detect structured aggregates of proteins, such as, collagen, myosin and tubulin. Since labeling techniques using chemical and biological reactions may cause undesirable changes in the sample, label-free molecular imaging techniques are essential for observation of living samples.

• 대한방사성의약품학회지
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• 제5권2호
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• pp.120-128
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• 2019

Radiopharmaceuticals include therapeutic radiopharmaceuticals and diagnostic radiopharmaceuticals. Therapeutic radiopharmaceuticals are administered to the body and ingested at specific organs to detect radiation emitted from the site and to construct an image to diagnose the disease. Diagnostic radiopharmaceuticals are used to treat diseases by killing cells with radiation emitted from radiopharmaceuticals, such as cancer cells, vascular endothelial cells, arthritis, and Alzheimer's disease. The application possibilities of terahertz imaging technology for the combination of radiopharmaceuticals and molecular imaging medicine are discussed and experimental methods are presented. Terahertz imaging is expected to be a powerful technique because of the effective piercing feasibility, which enables to perform safe and high resolutive imaging. To investigate the response of cell to the terahertz wave, both the pulsed and CW THz wave systems are employed. THz imaging of a rat's paraffin-embedded epithelial cell with tumor is studied in advance.

• 대한방사성의약품학회지
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• 제4권1호
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• pp.26-31
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• 2018

Macrophages play a key role in atherosclerotic plaque formation, but their participation has been discerned largely via ex vivo analyses of atherosclerotic lesions. Therefore, we aimed to identify atherosclerosis on noninvasive in vivo imaging using reporter gene system. This study demonstrated that recruitment of macrophages could be detected in atherosclerotic plaques of Apolipoprotein E knockout (ApoE-/-) mice with a sodium iodide symporter (NIS) gene imaging system using $^{99m}Tc-SPECT$. This novel approach to tracking macrophages to atherosclerotic plaques in vivo could have applications in studies of arteriosclerotic vascular disease.

• Nuclear Medicine and Molecular Imaging
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• 제42권2호
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• pp.164-171
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• 2008

Medical internal radiation dosimetry (MIRD) is an important part of nuclear medicine research field using therapeutic radioisotope. There have been many researches using MIRD for the development of new therapeutic approaches including radiopharmaceutical, clinical protocol, and imaging techniques. Recently, radionuclide therapy has been re-focused as new solution of intractable diseases, through to the advances of previous achievements. In this article, the basic concepts of radiation and internal radiation dosimetry are summarized to help understanding MIRD and its application to clinical application.

• Nuclear Medicine and Molecular Imaging
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• 제42권2호
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• pp.112-117
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• 2008

Artifact corrections including normalization and attenuation correction were important for quantitative analysis in Nuclear Medicine Imaging. Normalization is the process of ensuring that all lines of response joining detectors in coincidence have the same effective sensitivity. Failure to account for variations in LOR sensitivity leads to bias and high-frequency artifacts in the reconstructed images. Attenuation correction is the process of the correction of attenuation phenomenon lies in the natural property that photons emitted by the radiopharmaceutical will interact with tissue and other materials as they pass through the body. In this paper, we will review the several approaches for normalization and attenuation correction strategies.

• 대한방사성의약품학회지
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• 제3권2호
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• pp.72-79
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• 2017

Arbutin is a hydroquinone derivative with a glucose moiety. As a tyrosinase inhibitor, it is widely used as a skin-whitening cosmetic agent for the treatment of cutaneous hyperpigmentary disorders, such as melasma and freckles. In the medical field, many studies have addressed the use of arbutin in various tumors, but the mechanism for tumor uptake of arbutin is still unclear. In this paper, we radiolabeled arbutin using radioiodine and studied its pharmacokinetics and tumor uptake via biodistribution experiments and single-photon emission computed tomography (SPECT) imaging. Radiolabeled $^{131}I-arbutin$ was stable for up to 24 h in PBS and serum. Biodistribution studies and SPECT imaging indicated high uptake of the compound in the bladder and kidneys shortly after injection. Twenty-four hours post-injection, significant deiodination was observed. Apart from high thyroid uptake, selective tumor uptake was clearly observed. The tumor-to-muscle and tumor-to-blood ratios were 26 and 9, respectively.

• 대한방사성의약품학회지
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• 제4권1호
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• pp.3-10
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• 2018

The folate receptor (FR) is a promising cell membrane-associated target for nuclear imaging of various cancers (via imaging $FR-{\alpha}$) and potentially also inflammatory diseases (via imaging $FR-{\beta}$), through the use of folic acid-based radioconjugates. However, there have been several drawbacks of previously reported radioconjugates, such as a short half-life of the radiolabel ($^{68}Ga\;t_{1/2}$ 68 min), a complex and time-consuming multistep radiosynthesis, and a high renal uptake of radiolabeled folate derivatives. The goal of this study was to develop an imaging probe by directly labeling folate with radioactive iodine without using an extra prosthetic group. The radiolabeling of folate was optimized using various labeling conditions and the labeled tracers were isolated by high-performance liquid chromatography. The in vitro stability of labeled folate was checked in phosphate-buffered saline and serum. The tumor-targeting efficacy of the probe was also evaluated by biodistribution studies using a murine 4T1 tumor model.

• Molecules and Cells
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• 제42권2호
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• pp.104-112
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• 2019

Tracking the fate of individual cells and their progeny through lineage tracing has been widely used to investigate various biological processes including embryonic development, homeostatic tissue turnover, and stem cell function in regeneration and disease. Conventional lineage tracing involves the marking of cells either with dyes or nucleoside analogues or genetic marking with fluorescent and/or colorimetric protein reporters. Both are imaging-based approaches that have played a crucial role in the field of developmental biology as well as adult stem cell biology. However, imaging-based lineage tracing approaches are limited by their scalability and the lack of molecular information underlying fate transitions. Recently, computational biology approaches have been combined with diverse tracing methods to overcome these limitations and so provide high-order scalability and a wealth of molecular information. In this review, we will introduce such novel computational methods, starting from single-cell RNA sequencing-based lineage analysis to DNA barcoding or genetic scar analysis. These novel approaches are complementary to conventional imaging-based approaches and enable us to study the lineage relationships of numerous cell types during vertebrate, and in particular human, development and disease.

• Nuclear Medicine and Molecular Imaging
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• 제41권2호
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• pp.158-165
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• 2007

Technological advances in molecular imaging made it possible to image synaptic neurotransmitter concentration in living human brain. The dopaminergic system has been most intensively studied because of its importance in neurological as well as psychiatric disorders. This paper provides a brief overview of recent progress in imaging studies of dopamine release induced by pharmacologic and nonpharmacologic stimulations.