• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.9 no.2
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• pp.113-119
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• 2011

Safe operation and maintenance of engineered dry storage systems for spent fuel from nuclear power plants basically depends on adequately adopted design requirements. The most important design target of the system are those which provide the necessary assurances that spent fuel can be received, handled, stored and retrieved without undue risk to health and safety of workers and the public. To achieve these objectives, the design of the system incorporates features to remove spent fuel residual heat, to provide for radiation protection, and to maintain containment over the lifespan of the system as specified in the design specifications. The features also provide for all possible anticipated operational occurrences and design basis events in accordance with the design basis as guided by the designated regulations. The general performance requirements of a projected storage system are introduced in this paper. The storage system is designed to store fuel assemblies in associated with designated regulatory requirements. Small increases/decreases in maximum burnup can be adjusted with cooling time. These variations are compensated for by a corresponding small site-specific increase/decrease in the design basis-cooling period, as long as the maximum heat load and radioactivity of loaded fuel assemblies are met. Generic design basis events considered for the storage system are summarized. Shielding and radiological requirements along with mechanical and structural are derived in this study.

• The Korean Journal of Nuclear Medicine
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• v.24 no.1
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• pp.29-36
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• 1990

Most of the diagnostic methods currently used for the detection of neoplastic masses provide indirect evidence. To obtain greater specificity in the interpretation of neoplasias by in vivo methods, the immunological approach appears to be most promising. Two problems that interfered with progress in this field were the lack of tumor specific antigen and the lack of well-defined and reproducible antibodies. To improve the sensitivity and specificity of radioimmunoscintigraphy as a technique for tumor localization, the use of monoclonal antibodies, fragments of antibodies and single photon emission computerized tomography (SPECT) are reasonable. The obvious advantages of monoclonal antibodies are their homogeneity, their specificity for the immunizing antigen and the reaction with a single determinant-thus no large immunecomplexes with antigen are formed. Monoclonal antibody technique has recently provided an opportunity to reevaluate the role of nuclear medicine for the diagnosis of malignant diseases by using the immunological approach. Out first results by means of radioimmunoscintigraphy of CEA and CA 19-9 producing tumors using a cocktail of fragments F $(ab')_2$, of mocolonal antibodies to CA 19-9 and CEA labeled with $^{131}I$ (IMACIS-1) are reported. The aims of this investigation was to evaluate the role of immunoscintigraphy in patients with colorectal and other cancers for diagnosis of local recurrences and metastasis. This report contains results of the first 8 colorectal and pancreas cancer patients with the elevation of the level of serum CEA and/or CA 19-9. IMACIS-1 was injected intravenously during 30 minutes in 100 ml saline solution after skin test. Planar scintigrams were recorded 3, 5 and 7 days after the injection of the IMACIS-1. Anterior, lateral and posterior views of the liver as well as anterior and posterior views of the pelvis were obtained in each patients as an $^{131}I-antibody$ image. We were able to localize exactly the malignant process with the double-nuclide double-compound $^{99m}Tc\;^{131}I$ (Tc+l) scintigrams. In Tc & I double-nuclide scintigraphy, computer subtraction display provided more clear localization of the tumor. We compared the results of radioimmunoscintigraphy with CT, ultrasonograms, conventional scintigrams. The results were as follows: 1) The sensitivity and specificity of radioimmunoscintigraphy using the fragments $F(ab')_2$ of the cocktails of CEA and CA 19-9 monoclonal antibodies were 80% and 100% respectively. 2) Tumor detection rate was not proportionated to the level of serum tumor markets. 3) Second tracer technique was essential for tumor localization as an anatomic landmark using double-nuclide scintigraphy. 4) A slow infusion of the antibodies was necessary to prevent the formation of large immune complexes. 5) Tumor/non-tumor radioactivity was most elevated at 7 days delayed imaging. 6) Using planar scintigraphic technique of $^{131}I$ labeled monoclonal antibodies are possible for imaging most of the tumors.

• Nuclear Medicine and Molecular Imaging
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• v.40 no.4
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• pp.228-232
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• 2006

Purpose: electrophilic $^{18}F(T_{1/2}=110\;min)$ radionuclide in the form of $[^{18}F]F_2$ gas is of great significance for labeling radiopharmaceuticals for positron omission tomography (PET). However, its production In high yield and with high specific radioactivity is still a challenge to overcome several problems on targetry. The aim of the present study was to develop a method suitable for the routine production of $[^{18}F]F_2$ for the electrophilic substitution reaction. Materials and Methods: The target was designed water-cooled aluminum target chamber system with a conical bore shape. Production of the elemental fluorine was carried out via the $^{18}O(p,n)^{18}F$ reaction using a two-step irradiation protocol. In the first irradiation, the target filled with highly enriched $^{18}O_2$ was irradiated with protons for $^{18}F$ production, which were adsorbed on the inner surface of target body. In the second irradiation, the mixed gas ($1%[^{19}F]F_2/Ar$) was leaded into the target chamber, fellowing a short irradiation of proton for isotopic exchange between the carrier-fluorine and the radiofluorine absorbed in the target chamber. Optimization of production was performed as the function of irradiation time, the beam current and $^{18}O_2$ loading pressure. Results: Production runs was performed under the following optimum conditions: The 1st irradiation for the nuclear reaction (15.0 bar of 97% enriched $^{18}O_2$, 13.2 MeV protons, 30 ${\mu}A$, 60-90 min irradiation), the recovery of enriched oxygen via cryogenic pumping; The 2nd irradiation for the recovery of absorbed radiofluorine (12.0 bar of 1% $[^{19}F]fluorine/argon$ gas, 13.2 MeV protons, 30 ${\mu}A$, 20-30 min irradiation) the recovery of $[^{18}F]fluorine$ for synthesis. The yield of $[^{18}F]fluorine$ at EOB (end of bombardment) was achieved around $34{\pm}6.0$ GBq (n>10). Conclusion: The production of $^{18}F$ electrophilic agent via $^{18}O(p,n)^{18}F$ reaction was much under investigation. Especially, an aluminum gas target was very advantageous for routine production of $[^{18}F]fluorine$. These results suggest the possibility to use $[^{18}F]F_2$ gas as a electrophilic substitution agent.

• Journal of radiological science and technology
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• v.38 no.4
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• pp.337-345
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• 2015

After the Fukushima nuclear accident in 2011, concerns about radiation by people are increasing rapidly. If people could know how much they will be exposed by radiation, it may help them avoiding it and understand what exactly radiation is. By doing this, we were helping to reduce the anxiety of radiation contamination. In this study, we have researched figures of radioactivity with 'Captus-3000 thyroid uptake measurement systems' in well counter detector system. The materials were measured with Briquette, Shiitake, Pollock, Button type battery, Alkaline battery, Topsoil, Asphalt, Gasoline, Milk powder, Pine, Basalt stone, Pencil lead, Wasabi, Coarse salt, Tuna(can) Cigar, Beer, and then we categorized those samples into Land resources, Water resources, Foodstuff and Etc (Beer classified as a water resources has been categorized into Foodstuff). Also, we selected the standard radiation source linear 137Cs to measure the sensitivity of well counter detector. After that, we took cpm(counter per minute) for the well counter detector of thyroid uptake system's sensitivity. Then we compared the results of each material's cpm and converted those results to Bq/kg unit. There were a little limitation with the measurement equipment because it has less sensitivity than other professional equipment like 'High purity germanium radiation detector'. Moreover, We didn't have many choices to decide the materials. As a result, there are macroscopic differences among the rates of material's spectrum. Therefore, it had meaningful results that showed how much each material had emitted radiation. To compare the material's cpm with BKG, we've compounded their spectrums. By doing that, we were able to detect some differences among the spectrums at specific peak section. Lastly, Button type battery, Alkaline Battery, Briquette, Asphalt and Topsoil showed high value. There were classified emitting high radiation Group A and emitted lower radiation Group B. The Group A, alkaline battery showed higher rate of radiation by 7.67 %, and Button type battery was yield 4.65 % higher rate than BKG. Additionally, Asphalt (8.03 %), Topsoil (3.76 %), Briquette (7.46 %) were yield for higher values. Several samples of the daily supplies were yield little higher, but it seems safe to use in daily lives. In the case of the 'Foodstuff', all of the samples were safe and they were under the radiation limits of the Ministry of Food and Drug Safety for Food; thus, we highly recommend this study to you as a reference of common daily routine.

• The Korean Journal of Nuclear Medicine
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• v.29 no.1
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• pp.41-47
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• 1995

Tc-99m-MIBI(Sestamibi) myocardial SPECT along with T1-201 tomographic imaging has demonstrated wide application and high image qualify sufficient for the diagnosis of myocardial perfusion defect, which consequently reflects regional myocardial blood flow, The qualitative values of myocardial SPECT with Tc-99m-MIBI as well as the quantitative cases depend in some degree on the reconstruction techniques of multiple projections. Filtered backprojection(FBP) is the common standard for reconstruction rather than the complicated and time-consuming arithmetic methods. In FBP it Is known that the distribution of radioactivity in reconstructed transverse slices varies with the selected filter parameters such as cutoff frequencies and order(Butterworth case). The cutoff frequencies basically remove and decrease the true radioactive distribution and alter the pixel counts, which lead to underestimation of true counts in specific myocardial regions. In this study, we have investigated the effect of cutoff frequencies of reconstruction filter on the artifactually induced perfusion defects, which are often demonstrated near inferior and/or inferoseptal cardiac walls due to the intense hepatic uptake of Tc-99m-MIBI. A computerized method for identifying the relative degree of artifactual perfusion defect and for comparing those degrees along with the relative amount of hepatic uptake to myocardium was developed and patient images were studied to observe the quantitative degree of underestimation of myocardial perfusion, and to propose some reasonable thresh-old of cutoff frequency in the diagnosis of perfusion defect quantitatively. We concluded that from the quantitative viewpoint cutoff frequencies may be used as high as possible with the sacrifice of homogeneity of image quality, and those frequencies lower than the common 0.3 Nyquist frequency would reveal severe degradation of radio-active distribution near inferior and/or Inferoseptal myocardium when applying Butterworth or low pass filter.

• The Korean Journal of Nuclear Medicine Technology
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• v.22 no.2
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• pp.79-83
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• 2018

Purpose $^{18}F-FDG$, which is commonly used in PET-CT examinations, is low in capacity and it is difficult to keep the amount of radioactivity busy when the specific activity is high, increasing the amount of space dose and radioactive contamination in the distribution room. Therefore, while evaluating the actual dose administered to patients during the manual dispense process, the medical institution intends to assess the usefulness of the auto dispenser by comparing the differences from the actual dose administered to the patient using the new automatic dispense. Materials and Methods From July 2016 to December 2016, 846 patients were manually administered by workers using $^{18}F-FDG$ and $^{18}F-FDG$ 906 patients were using auto dispenser from July 2017 to December 2017. Results Capacity administered to patients during the manual dispense averaged $35.41{\pm}27.79%$ compared to the recommended dose, and the auto dispenser process showed a small difference of $-2.15{\pm}3.99%$ compared to the recommended dose(p<0.05). Conclusion Working people did not have to touch radioactive medicines directly while they were busy in the auto dispenser, and because of the availability of other tasks far away, the time and distance to receive the exposure were also advantageous. It is believed that future use by many medical institutions will not only reduce the dose to patients but also help reduce the exposure dose to workers.