• Journal of Radiopharmaceuticals and Molecular Probes
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• v.4 no.1
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• pp.32-35
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• 2018

Since utilization of metal is attractive research area applicable to medical applications, several metals have been studied by many scientists. Zr-89 is known as one of important radioisotopes nowadays. Novel ligands for Zr-89 have been developed, and Zr-89-based radiopharmaceuticals have been employed for positron emission tomography (PET) study. In this highlight review, recent advances on Zr-89 utilization for radiophramaceuticals are illustrated.

• Journal of Radiopharmaceuticals and Molecular Probes
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• v.6 no.1
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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.

• Journal of Radiopharmaceuticals and Molecular Probes
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• v.1 no.1
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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.

• Journal of Radiopharmaceuticals and Molecular Probes
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• v.7 no.2
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• pp.153-159
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• 2021

This article provides an efficient ¹⁸F-labeling protocol based on a rapid condensation reaction between 2-cyanobenzothiazole (CBT) and N-terminal cysteine-containing biomolecules. The ¹⁸F-labeled CBT (¹⁸F-1) was prepared by radiofluorination of the tosylated precursor 4 with 18-crown-6/K+/[¹⁸F]F- complex. Using the purified ¹⁸F-1, ¹⁸F-labeled peptide (¹⁸F-7) and protein (¹⁸F-8) could be synthesized efficiently under mild conditions. This strategy would provide a convenient approach for rapid and site-specific ¹⁸F-labeling of various peptides and proteins for in vivo imaging and biomedical applications.

• Journal of Radiopharmaceuticals and Molecular Probes
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• v.6 no.2
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• pp.116-130
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• 2020

The aging society is globally one of biggest issue because it is related with various degenerative brain disease such as dementia, Parkinson's disease, Alzheimer's disease, multiple sclerosis, and cerebrovascular disease. These diseases are characterized by misfolded-protein aggregation; another pathological trait is "neuroinflammation". In physiological state, the resting microglia cells are activated and it removes abnormal synapses and cell membrane debris to maintain the homeostasis. In pathological state, however, microglia undergo morphological change form 'resting' to 'activated amoeboid phenotype' and the microglia cells are accumulated by neuronal damage, the inflammatory reactions induced nerve metamorphosis with a variety of neurotoxic factors including cytokines, chemokines, and reactive oxygen species. Thus, the activated microglia cell with various receptors (TSPO, COX, CR, P2XR, etc.) was perceived as important biomarkers for imaging the inflammatory progression. In this review, we would like to introduce the current status of the development of radiotracers that can image activated microglia.

• Journal of Radiopharmaceuticals and Molecular Probes
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• v.6 no.2
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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.

• Journal of Radiopharmaceuticals and Molecular Probes
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• v.6 no.2
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• pp.165-170
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• 2020

Histone Deacetylases (HDACs) are enzymes that have control gene expression regulation and cell state. In additions, inhibitions of HDACs are associated with growth arrest, differentiation, or apoptosis of tumor cell. Thus HDAC inhibition is one of the interesting biological targets. A variety of HDAC inhibitors has been developed by many scientists, and some of chemical structures related with HDAC inhibitors were modified to give radiolabeled HDAC inhibitors for positron emission tomography (PET) study. In this highlight review, the development of radiolabeled HDAC inhibitors for PET study are described.

• Journal of Radiopharmaceuticals and Molecular Probes
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• v.1 no.1
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• pp.62-73
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• 2015

We developed an evans blue-indocyanine green-$^{99m}Tc$-human serum albumin conjugate for sentinel lymph node mapping and we describe its unique potential usage for clinical implications. This conjugate has combined the strengths of visible blue dye, near-infrared fluorescence and radioisotope into one single conjugate without any additional weakness/disadvantage. All the components of evans blue-indocyanine green-$^{99m}Tc$-human serum albumin are safe and of low cost, and they have already been clinically used. This conjugate was stable in the serum, it showed a long retention time in the lymphatic system and the lymph nodes showed a much higher signal-to-noise ratio after the conjugate was injected intradermally into the paw of mice. Both the single-photon emission computed tomography and near-infrared fluorescent images of the mice were successfully obtained at the same time as the excised sentinel lymph nodes showed blue color. The visual color, near-infrared fluorescence and gamma ray from this agent could be complementary for each other in all the steps of sentinel lymph node sampling: exploring and planning sentinel lymph node before excision with visualization of the exact sentinel lymph node location during an operation. Therefore, the triple modal agent will possibly be very ideal for sentinel lymph node mapping because of the high signal-to-noise ratio for non-invasive imaging and its complementary multimodal nature, easy preparation and safety. It is promising for clinical applications and it may have great advantages over the traditional single modal methods.

• Nuclear Medicine and Molecular Imaging
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• v.43 no.3
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• pp.229-239
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• 2009

Molecular imaging strives to visualize processes in living subjects at the molecular level. Monitoring biochemical processes at this level will allow us to directly track biological processes and signaling events that lead to pathophysiological abnormalities, and help make personalized medicine a reality by allowing evaluation of therapeutic efficacies on an individual basis. Although most molecular imaging techniques emerged from the field of oncology, they have now gradually gained acceptance by the cardiovascular community. Hence, the availability of dedicated high-resolution small animal imaging systems and specific targeting imaging probes is now enhancing our understanding of cardiovascular diseases and expediting the development of newer therapies. Examples include imaging approaches to evaluate and track the progress of recent genetic and cellular therapies for treatment of myocardial ischemia. Other areas include in vivo monitoring of such key molecular processes as angiogenesis and apoptosis, Cardiovascular molecular imaging is already an important research tool in preclinical experiments. The challenge that lies ahead is to implement these techniques into the clinics so that they may help fulfill the promise of molecular therapies and personalized medicine, as well as to resolve disappointments and controversies surrounding the field.

• Journal of Radiopharmaceuticals and Molecular Probes
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• v.2 no.2
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• pp.103-107
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• 2016

Solid phase extraction (SPE) purification method is the efficient and well-known tool for automated [$^{11}C$]acetate synthesis. A fully automated homemade module adopting the SPE method and 'pinch' valves was developed very economically with a universal interface board, a relay card and an open source programmable logic controller. The radiochemical yield of the optimized [$^{11}C$]acetate synthesis by this system was $58.8{\pm}2.1%$ (n=10, decay-corrected) from $15.5{\pm}0.19GBq$ of $[^{11}C]CO_2$ as starting activity, and total synthetic time was 15 minutes. HPLC analysis showed its high radiochemical purity as $97.4{\pm}1.1%$ without possible by-products.