• The Korean Journal of Nuclear Medicine
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• v.35 no.3
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• pp.117-124
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• 2001

Serum thyroglobulin measurement and I-131 whole-body scintigraphy (WBS) are well-established methods for the detection of recurrence in the follow-up of patients with thyroid carcinoma. However, inconsistent results are observed frequently, and these two methods are not always able to detect recurrence. In some patients, serum thyroglobulin level is elevated but the WBS is negative, because the recurrent tumor is too small and below the sensitivity of the diagnostic scan, or there is a dissociation between thyroglobulin synthesis and the iodine frapping mechanism. In such cases, various nuclear imaging methods including Tl-201 Tc-99m-sestamibi, and F-18-FDG PET can be used besides anatomical imaging methods. Among them, FDG PET localizes recurrent lesions in WBS-negative thyroid carcinoma with high accuracy. Several studies have suggested that empirical high-dose I-131 therapy resulted in a high rate of visualization in post-therapy scans with evidence of subsequent improvement. An important question is when to operate on patients with recurrent tumor. We believe that surgical removal is the best means of treatment for patients with localized persistent tumor, despite the high-dose I-131 therapy. with tumor in thyroid remnant, and with isolated recurrence in the lymph node, lung or bone. In addition, we recommend palliative resection of locally unresectable mass with subsequent treatment with high-dose I-131 therapy. Before I-131 therapy, the evaluation of sodium-iodide symporter expression in thyroid carcinoma can predict iodine uptake. Retinoic acid is known to induce redifferentiation, and to enhance I-131 uptake in thyroid carcinoma. Retinoic acid therapy may represent an alternative approach before high-dose I-131 therapy.

• Nuclear Engineering and Technology
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• v.38 no.5
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• pp.399-404
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• 2006

Noninvasive molecular targeting in living subjects is highly demanded for better understanding of such diverse topics as the efficient delivery of drugs, genes, or radionuclides for the diagnosis or treatment of diseases. Progress in molecular biology, genetic engineering and polymer chemistry provides various tools to target molecules and cells in vivo. We used chitosan as a polymer, and $^{99m}Tc$ as a radionuclide. We developed $^{99m}Tc-galactosylated$ chitosan to target asialoglycoprotein receptors for nuclear imaging. We also developed $^{99m}Tc-HYNIC-chitosan-transferrin$ to target inflammatory cells, which was more effective than $^{67}Ga-citrate$ for imaging inflammatory lesions. For an effective delivery of molecules, a longer circulation time is needed. We found that around 10% PEGylation was most effective to prolong the circulation time of liposomes for nuclear imaging of $^{99m}Tc-HMPAO-labeled$ liposomes in rats. Using various characteristics of molecules, we can deliver drugs into targets more effectively. We found that $^{99m}Tc-labeled$ biodegradable pullulan-derivatives are retained in tumor tissue in response to extracellular ion-strength. For the trafficking of various cells or bacteria in an intact animal, we used optical imaging techniques or radiolabeled cells. We monitored tumor-targeting bacteria by bioluminescent imaging techniques, dentritic cells by radiolabeling and neuronal stem cells by sodium-iodide symporter reporter gene imaging. In summary, we introduced recent achievements of molecular nuclear imaging technologies in targeting receptors for hepatocyte or inflammatory cells and in trafficking bacterial, immune and stem cells using molecular nuclear imaging techniques.

• Nuclear Engineering and Technology
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• v.4 no.3
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• pp.186-193
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• 1972

For efficient micro scale syntheses of Rose $Bengal-^{131}I$, $Hippuran-^{131}I$, and $H.S.A.-^{131}I$, the dependence of labelling yields on pH, on salt contents, and on the volume of buffer solution in the reaction mixtures as well as the reaction apparatus were studied. pH of 5.6 was optimum for preparation of both Rose $Bengal-_{131}I$ and Hippuran $-^{13}I$ but pH of 8.5 was optimum for preparation of $H.S.A.-^{131}I$. Salt in the reaction mixtures hindered drastically the formation of $Hippuran-^{131}I$ but it slightly increased the labelling yield of H.S.A.. The compactly closed reaction vessels were effective for preparations of both Rose $Bengal-^{131}I$and $Hippuran-^{131}I$ in small volume. Thereupon, the labelling procedures were modified to bring about higher labelling yields and better reproducibilities. By these newly established procedures, the labelling yields of Rose $Bengal-^{131}I$ and $Hippuran-^{131}I$ could be increased even with the home-produced sodium $iodide-^{131}I$ solution containing reducing agent.

• Proceedings of the Korean Biophysical Society Conference
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• 2003.06a
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• pp.51-51
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• 2003

The medicinal plant Cimicifuga Racemosa (Black cohosh) has been used to treat many kinds of neuronal and menopausal symptoms, such as arthritis, menopausal depression, nerve pain, etc. Here, we examined the effect of Cimicifugoside (CF), one of triterpene glycosides which have been known as pharmacologically active ingredients of C. Racemosa, on nicotinic acetylcholine receptor (nAChR)-mediated catecholamine (CA) secretion in bovine adrenal chromaffin cell. Cimicifugoside inhibited calcium increase induced by 1,1-dimethyl-4-phenylpiperazinium iodide (DMPP), a nAChR agonist with a half maximal inhibitory concentration (IC50) of 18${\pm}$2${\mu}$M. In contrast, cimicifugoside did not affect the calcium increases evoked by high K$\^$+/, veratridine, and bradykinin. The DMPP-induced sodium increase was also inhibited by cimicifugoside with IC50 of 2${\pm}$0.3${\mu}$M, suggesting that the activity of nAChRs is inhibited by cimicifugoside. Cimicifugoside did not effect on the KCl-induced secretion but markedly inhibited the DMPP-induced catecholamine secretion which was monitored by carbon-fiber amperometry in real time, and by high performance liquid chromatography (HPLC) through electrochemical detection. The results suggest that cimicifugoside selectively inhibits nAChR-mediated response in bovine chromaffin cells.

• Nuclear Engineering and Technology
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• v.34 no.1
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• pp.42-59
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• 2002

In order to transmute long-lived radioactive nuclides such as transuranics(TRU), Tc-99, and I- l29 in LWR spent fuel, a preliminary conceptual design study has been performed for the accelerator driven subcritical reactor system, called HYPER(Hybrid Power Extraction Reactor) The core has a hybrid neutron energy spectrum: fast and thermal neutrons for the transmutation of TRU and fission products, respectively. TRU is loaded into the HYPER core as a TRU-Zr metal form because a metal type fuel has very good compatibility with the pyre- chemical process which retains the self-protection of transuranics at all times. On the other hand, Tc-99 and I-129 are loaded as pure technetium metal and sodium iodide, respectively. Pb-Bi is chosen as a primary coolant because Pb-Bi can be a good spallation target and produce a very hard neutron energy spectrum. As a result, the HYPER system does not have any independent spallation target system. 9Cr-2WVTa is used as a window material because an advanced ferritic/martensitic steel is known to have a good performance under a highly corrosive and radiation environment. The support ratios of the HYPER system are about 4∼5 for TRU, Tc-99, and I-129. Therefore, a radiologically clean nuclear power, i.e. zero net production of TRU, Tc-99 and I-129 can be achieved by combining 4 ∼5 LWRs with one HYPER system. In addition, the HYPER system, having good proliferation resistance and high nuclear waste transmutation capability, is believed to provide a breakthrough to the spent fuel problems the nuclear industry is faced with.

• Nuclear Engineering and Technology
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• v.51 no.4
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• pp.1091-1097
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• 2019

After the Fukushima accident in 2011, there has been increased public concern about radioactive contamination of water resources through fallout in neighboring countries. However, there is still no available initial response system that can promptly detect radionuclides. The purpose of this research is to develop the most efficient gamma spectrometer to monitor radionuclides in an aquatic environment. We chose a thallium-doped sodium iodide (NaI(Tl)) scintillator readout with a silicon photo multiplier (SiPM) due to its compactness and low operating voltage. Three types of a scintillation detector were tested. One was composed of a scintillator and a photomultiplier tube (PMT) as a reference; another system consisted of a scintillator and an array of SiPMs with a light guide; and the other was a scintillator directly coupled with an array of SiPMs. Among the SiPM-based detectors, the direct coupling system showed the best energy resolution at all energy peaks. It achieved 9.76% energy resolution for a 662 keV gamma ray. Through additional experiments and a simulation, we proved that the light guide degraded energy resolution with increasing statistical uncertainty. The results indicated that the SiPM-based scintillation detector with no light guide is the most efficient design for monitoring radionuclides in an aquatic environment.

• Restorative Dentistry and Endodontics
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• v.44 no.1
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• pp.4.1-4.10
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• 2019

Objectives: Biofilm formation is critical to dental caries initiation and development. The aim of this study was to investigate the effects of nicotine exposure on Streptococcus mutans (S. mutans) biofilm formation concomitantly with the inhibitory effects of sodium chloride (NaCl), potassium chloride (KCl) and potassium iodide (KI) salts. This study examined bacterial growth with varying concentrations of NaCl, KCl, and KI salts and nicotine levels consistent with primary levels of nicotine exposure. Materials and Methods: A preliminary screening experiment was performed to investigate the appropriate concentrations of NaCl, KCl, and KI to use with nicotine. With the data, a S. mutans biofilm growth assay was conducted using nicotine (0-32 mg/mL) in Tryptic Soy broth supplemented with 1% sucrose with and without 0.45 M of NaCl, 0.23 M of KCl, and 0.113 M of KI. The biofilm was stained with crystal violet dye and the absorbance measured to determine biofilm formation. Results: The presence of 0.45 M of NaCl, 0.23 M of KCl, and 0.113 M of KI significantly inhibited (p < 0.05) nicotine-induced S. mutans biofilm formation by 52%, 79.7%, and 64.1%, respectively. Conclusions: The results provide additional evidence regarding the biofilm-enhancing effects of nicotine and demonstrate the inhibitory influence of these salts in reducing the nicotine-induced biofilm formation. A short-term exposure to these salts may inhibit S. mutans biofilm formation.

• Journal of Radiation Protection and Research
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• v.48 no.3
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• pp.153-161
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• 2023

Background: Fukushima Medical University (FMU) is located 57 km northwest of the Fukushima Daiichi Nuclear Power Plant. Our laboratory has been conducting environmental radiation measurements continuously before and after the nuclear accident. We aimed to report the observed behavior of radiation originating from the released radioactive materials due to the accident, predict future trends, and disseminate the results to the local residents. Materials and Methods: Measurements of the counting rate by a diameter of 76 mm and a length of 76 mm thallium-doped sodium iodide (NaI[Tl]) scintillation detector (S-1211-T; Teledyne Brown Engineering Environmental Services) in the central part of the laboratory, and the dose rate outward at the window by NaI(Tl) scintillation detector and digital processor (EMF211; EMF Japan Co. Ltd.) were conducted. Results and Discussion: Measurements by Teledyne S-1211-T showed that in the early stages, radiation from radioactive isotopes with short half-lives was dominant, while radiation from radioactive isotopes with longer half-lives became dominant as the measurement period became longer. Through nonlinear least squares regression, both short and long half-lives were successfully determined. It was also possible to predict how the radiation dose would decrease. The environmental radiation trends around FMU were measured by the EMF211. Both measurements were affected by rainfall and snow accumulation. Decontamination work on the FMU campus impacted measurements by the EMF211 especially. Conclusion: The results of two types of measurements, one at the center and the other at the window side of the laboratory, were presented. By applying a simplified model, radiation from radioactive isotopes with short and long half-lives was identified. Based on these results, future trends were predicted, and the information was used for public communication with the local residents.

• Nuclear Medicine and Molecular Imaging
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• v.40 no.1
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• pp.9-15
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• 2006

Purpose: Previous studies have not showed consistent results for the level of expression of sodium/iodide symporter (NIS) in thyroid diseases, especially malignant tumor. We undertook this study to evaluate the distribution of NIS expression in malignant thyroid diseases and compare with that in benign thyroid disease. Materials and Methods: Total patients were 119 cases (Men 15, $48{\pm}13$ yrs). Total number of samples were 205 pieces. In malignant thyroid disease, there were 153 samples: 90 in papillary carcinoma, 4 in follicular carcinoma, 2 in medullary carcinoma and 57 in metastatic lymph node. In benign thyroid disease, there were 52 samples: 36 in goiter/cyst, 11 in thyroiditis and 5 in follicular adenoma. Using immunohistochemical methods, we probed 205 samples with monoclonal anti-NIS Ab. Grading of staining was stored as 0 (negative or absent), 1 (weakly positive), 2 (moderately positive) or 3 (strongly positive). Expression rate (ER) of NIS positivity in individual disease entity was expressed as percentage of total number divided by number in 2 plus 3 grade. Results: ERs of malignant thyroid diseases were 63% in papillary carcinoma, 81% in metastatic lymph node, 71% in follicular carcinoma and 100% in medullary carcinoma. ERs of benign thyroid disease were 53% in goiter/cyst, 64% in thyroiditis and 40% in follicular adenoma. ER of malignant thyroid diseases was higher than benign thyroid diseases (71% vs 54%). Grading of NIS expression in papillary carcinoma or goiter/cyst was heterogeneously distributed in considerable cases. Normal tissue also showed heterogeneous distribution of NIS expression, which was not correlated with that of primary lesion. Conclusion: In papillary thyroid carcinoma, distribution of NIS expression was heterogeneous and increased, and not different compared with that of benign thyroid disease.

• Nuclear Medicine and Molecular Imaging
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• v.41 no.3
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• pp.226-233
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• 2007

Purpose: Dual reporter gene imaging has several advantages for more sophisticated molecular imaging studies such as gene therapy monitoring. Herein, we have constructed hepatoma cell line expressing dual reporter genes of sodium iodide symporter (NIS) and enhanced green fluorescence protein (EGFP), and the functionalities of the genes were evaluated in vivo by nuclear and optical imaging. Materials and Methods: A pRetro-PN vector was constructed after separating NIS gene from pcDNA-NIS. RSV-EGFP-WPRE fragment separated from pLNRGW was cloned into pRetro-PN vector. The final vector expressing dual reporter genes was named pRetro-PNRGW. A human hepatoma (HepG2) cells were transfected by the retrovirus containing NIS and EGFP gene (HepG2-NE). Expression of NIS gene was confirmed by RT-PCR, radioiodine uptake and efflux studies. Expression of EGFP was confirmed by RT-PCR and fluorescence microscope. The HepG2 and HepG2-NE cells were implanted in shoulder and hindlimb of nude mice, then fluorescence image, gamma camera image and I-124 microPET image were undertaken. Results: The HepG2-NE cell was successfully constructed. RT-PCR showed NIS and EGFP mRNA expression. About 50% of cells showed fluorescence. The iodine uptake of NIS-expressed cells was about 9 times higher than control. In efflux study, $T_{1/2}$ of HepG2-NE cells was 9 min. HepG2-NE xenograft showed high signal-to-background fluorescent spots and higher iodine-uptake compared to those of HepG2 xenograft. Conclusion: A hepatoma cell line expressing NIS and EGFP dual reporter genes was successfully constructed and could be used as a potential either by therapeutic gene or imaging reporter gene.