• The Korean Journal of Nuclear Medicine
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• v.34 no.2
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• pp.129-134
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• 2000

Purpose: It is difficult to determine the activity of tuberculosis radiologically. Therefore there have been efforts to assess the activity using radiopharmaceuticals such as $^{67}Ga,\;^{99m}Tc-tetrofosmin,\;and\;^{99m}Tc-MIBI$. But there may be some discrepancy in defining the term 'activity' between clinicians and nuclear physicians. While negative conversion of sputum acid fast bacilli (AFB) is defined as 'disappearance of activity' by clinicians, a loss of uptake in previously positive lesion is accepted as 'disappearance of activity' by nuclear physicians. We designed a prospective study to see if the negative conversion of sputum AFB could directly match the disappearance of radioactivity of the lesion. Materials and Methods: Fifteen patients with bacteriologically confirmed active localized pulmonary tuberculosis were scanned 10 and 60 min after intravenous injection of 550 MBq $^{99m}Tc$-MIBI. In 6 patients, who showed negative conversion of sputum AFB after 3-7 months of chemotherapy, $^{99m}Tc$-MIBI scan was repeated. For the purpose of comparison, target/nontarget ratios of the lesions were determined. Results: 12/15 (80%) patients with active pulmonary tuberculosis showed increased uptake of $^{99m}Tc$-MIBI in tuberculous lesion. After negative conversion of sputum AFB, 5/6 (83%) patients still showed increased uptake, although the intensity of uptake decreased. Conclusion: Uptake of radioactivity decreased but did not disappear after negative conversion of sputum AFB. $^{99m}Tc$-MIBI scan may be useful to address the degree of inflammation of pulmonary tuberculous lesion, but the uptake did not directly match the activity defined by positivity of sputum AFB. We nuclear physicians might have used the term 'activity' somewhat differently from clinicians who treat patients with tuberculosis.

• Proceedings of the Korean Radioactive Waste Society Conference
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• 2018.05a
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• pp.285-286
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• 2018

• 대한방사선방어학회:학술대회논문집
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• 2011.11a
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• pp.212-213
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• 2011

The biological effects of low dose ionizing radiation (LDIR) remain insufficiently understood. We examined for the scientific evidence to show the biological effects of LDIR using radiation-sensitive immune cells. We found that Ikaros protein was responsed to low dose-dependent effects of gamma radiation in IM-9 B lymphocytes. Ikaros encodes zinc finger transcription factors that is important regulators of a hematopoietic stem cells (HSCs) progression to the B lymphoid lineage development, differentiation and proliferation. In this study, we observed that cell proliferation was enhanced from 10% to 20% by LDIR (0.05 Gy) in IM-9 B lymphocytes. The Ikaros protein was phosphorylated in its serine/threonine (S/T) region and decreased its DNA binding activity in the cells exposed to LDIR. We found that Ikaros phosphorylation was up-regulated by CK2/AKT pathway and the residues of ser-304 and ser-306 in Ikaros was phosphorylated by LDIR. We also observed that Ikaros protein was localized from the nucleus to the cytoplasm after LDIR and bound with Autotaxin (ENPP2, ATX) protein, stimulating proliferation, migration and survival of immune cells. In addition, we found that the lysoPLD activity of ATX was dependent on Ikaros-ATX binding activity. These results indicate that the Ikaros is an important regulator of immune activation. Therefore, we suggest that low dose ionizing radiation can be considered as a beneficial effects, stimulating the activation of immune cells.

• Nuclear Engineering and Technology
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• v.53 no.6
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• pp.1991-1999
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• 2021

The response changes of the specific growth rate of Lemna minor duckweed was modeled using the logarithms of frond numbers on tritium activity concentration and gamma radiation dose from cobalt 60. The concept of average specific growth rate depends on the general exponential growth pattern, where toxicity is estimated based on the effect on the growth rate. One of the main questions of the effect of the radiation dose on duckweed is how to correlate the effect of beta radiation with the effect of any other radiation for modeling radiation on Lemna minor. Experimental data were extrapolated by utilizing the OECD guidelines. A linear relationship of absorbed dose and activity concentration was obtained for the average dependency growth rate of Lemna minor as D = (0.1257)·A^0.585. The dose rate of gamma irradiation from ⁶⁰Co increases with tritium activity dependence, on the specific growth rate of the Lemna minor duckweed. An increase in the tritium activity causes a decrease in the specific growth rate of the Lemna minor duckweed. It indicates that as the quantity of the beta radiation dose increase in Lemna minor duckweed, a higher quantity of gamma radiation will be required to cause the same effect in the specific growth rate of Lemna minor duckweed. The relation between the inhibition of the Lemna minor seedling growth and gamma and beta radiation dosage agrees roughly with that between the decrease of survival rate or fertility and dosage.

• Journal of Radiopharmaceuticals and Molecular Probes
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• v.4 no.1
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• pp.22-25
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• 2018

Radiopharmaceuticals are used for diagnosis or therapy of diseases. According to the recent consensus nomenclature rules for radiopharmaceutical chemistry, specific activity is defined as the radioactivity per gram of radiolabeled compound and molar activity as the radioactivity per mole of radiolabeled compound. In this review, molar activity of radiopharmaceuticals is discussed in terms of its significance in nuclear imaging as well as its measurement methods.

• Journal of Embryo Transfer
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• v.23 no.1
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• pp.31-36
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• 2008

We attempted to control the maturation promoting factors (MPF) activity and nuclear remodeling of somatic cell nuclear transfer (NT) bovine embryos. Bovine ear skin fibroblasts were fused to enucleated oocytes treated with either 5 mM caffeine for 2.5 h or 0.5 mM vanadate for 0.5 h and activated. The nuclear remodeling type of the reconstituted embryos was evaluated 1.5 h after activation. MPF activity was assessed in enucleated and chemical treated oocytes before the injection of a donor cell. Effect of chemicals on the embryonic development was evaluated with parthenogenetic embryos. MPF activity increased significantly by caffeine treatment, but decreased by vanadate treatment (p<0.05). Caffeine or vanadate had no deleterious effect on the parthenogenetic embryo development. In caffeine treated group, premature chromosome condensation (PCC) was occurred in 72.2% of NT embryos (p<0.05). In contrast, vanadate induced the formation of a pronucleus-like structure (PN) in a high frequency (68.9%, p<0.05) without PCC (NPCC). Blastocyst development of NT embryos increased by treating with caffeine (30.3%), whereas decreased by treating with vanadate (11.4%) compared to control (22.1%, p<0.05). The results indicate that caffeine or vanadate can control of MPF activity and remodeling type of NT embryos, resulting in the increased or decreased in vitro development.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.16 no.1
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• pp.65-82
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• 2018

With the significant increase in spent ion-exchange resin generation, to meet the requirements of Waste Acceptance Criteria (WAC) of the Wolsong disposal facility in Korea, blending is considered as a method for enhancing disposal options for intermediate level waste from nuclear reactors. A mass balance formula approach was used to enable blending process with an appropriate mixing ratio. As a result, it is estimated around 44.3% of high activity spent resins can be blended with the overall volume of low activity spent resins at a 1:7.18 conservative blending ratio. In contrast, the reduction of high activity spent resins is considered a positive solution in reducing the amount of spent resins stored. In an economic study, the blending process has been proven to lower the disposal cost by 10% compared to current APR1400 treatment. Prior to commencing use of this blending method in Korea, coordinated discussion, and safety and health assessment should be undertaken to investigate the feasibility of fitting this blending method to national policy as a means of waste predisposal processing and management in the future.

• Nuclear Engineering and Technology
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• v.51 no.4
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• pp.1169-1175
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• 2019

The minimum detectable activity (MDA) value was derived according to the flow rate of the sample and degree of amplification of the device by sending the sample directly from the collection site to the detection part through a pump. This method can lead to reduction in time and cost compared to the existing measurement method that uses a pre-treatment process. In this study, experiments were conducted on $^3H$ and $^{90}Sr$, which are the major pure beta-emitting radionuclides, by setting the sample flow rate and the amplification gain as factors. The MDA values were derived according to the flow rates, considering that the flow rate can affect the MDA values. There were no change in the MDA under different flow rates of 0, 600, 800, and 1000 mL/min. Therefore, it was confirmed that the flow rate may not be considered when collecting samples for monitoring in actual field. As the degree of amplification of the amplifier increased, the time required to reach the target MDA decreased. When the amplification was quadrupled, the detection efficiency increased by approximately 23.4 times, and the time to reach the MDA decreased to approximately 1/550 times. This method offers the advantage of real-time on-site monitoring.

• The Korean Journal of Nuclear Medicine
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• v.27 no.1
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• pp.71-80
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• 1993

In order to evaluate the scintigraphic features of choledochal cyst and these diagnostic value, authors investigated the findings of fourteen patients with choledochal cyst undergone hepatobiliary scan with $^{99m}Tc$-DISIDA before surgery. Five cases demonstrated the decreased hepatic uptake at 5-minute image of which four cases revealed severe jaundice. Seven cases demonstrated visualization of the cystic dilated common bile duct within 1 hour after injection. Two cases showed the cyst activity between 1 and 12 hours, but the cyst activity was not visible in five cases. Nonvisualization of the gall bladder was noted in ten cases, while four cases demonstrated visualization of the gall bladder within 1 hour. The time of visualization of gut activity was variably delayed. The intestinal activity was found in three cases within 1 hour and appeared in three cases between 1 and 2 hours and eight cases showed no visible gut activity. In four cases, intrahepatic ductal prominence was visible on the scintigram. Seven cases showed early and persistent accumulation of tracer in the common bile duct. Three cases showed persistent photon-deficient area in the gall bladder region. Two cases showed early photon-deficient area around gall bladder region with progressive accumulation of tracer in the same region. Two cases showed no evidence of activity in the biliary tract but noted late excretion into the small intestine. We concluded that hepatobiliary scan using $^{99m}Tc$-DISIDA is a noninvasive test useful in the evaluation and the diagnosis of choledochal cyst.

• The Korean Journal of Zoology
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• v.11 no.3
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• pp.85-91
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• 1968

Artificial and natural radioactivity in airborne, rain-out and fallout dusts in Seoul district in the period of 1963-1967 were studied by measuring gross-activity and by analyzing nuclides by means of $\\gamma$-spectrometry. Short-lived radium and thorium decay products give rise to most of the airborne activity unless the fission product concentration is extremely high and it is likely to be said activity remaining after a few days is attributable to fission products. Of seven Chinese nuclear explosions performed at Lop Nor, Sinkiang Province, two exhibited the activity of extremely high concentration of fission product and reached Seoul district around 30 hours after the explosion. The activity was followed by a sudden decrease in less than a week, in contrast to the long-lasted activity of low concentration originating from the huge tests performed by the United States and the USSR in 1956-1962. The radioactive environmental contamination in Seoul district, due to the Chiness nuclear test explosions, largely depends on the height above the earth at which the nuclear explosion is performed and the type of nuclear device as well as the weather system at the time and immediately after the explosion, especially the jet stream in middle latitude in the upper troposphere.