• Journal of the Korean Society of Food Culture
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• v.17 no.2
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• pp.141-152
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• 2002

This study provides a national examination on youths' 'understanding' of irradiated food. The 1,200 subjects of the survey were randomly sampled from male and female students throughout the nation, between grades five and eleven. The survey was conducted toward these samples in November 2000. The number of respondents with exposure to irradiated food was so small, amounting to only 4.0 percent of the whole sample. The core concept used in this study is 'impression'. An impression is information about a specific subject, which carries significance to an individual. The results show that the higher the grade was, the more value the contents of impression contained. Furthermore, impressions concerning atomic or nuclear energy, and radioactivity increased greatly among students in middle school and above. Providing information of effects and advantages of irradiated food was focused to increase positive impressions and decrease the negative ones more greatly than providing simple factual information. Youths showed less value-centered impressions of irradiated food and more impressions centered on fragmented facts than adults. Respondents previously exposed irradiated food were shown to acquire the most of their information from the television and newspaper media. Among six information sources presented in the survey, youths pointed out 'science and technology research institutes' as the most credible. International organizations and environmental/ consumer organizations were evaluated as having relatively high credibility. Providing simple factual information of irradiated food did not seem to bring about any difference to the intention of purchasing irradiated food. On the other hand, respondents provided with effects-included information showed an increase in such intention. Our research results of the youth show a notable difference with that of the adults. Thus, programs and strategies to enhance youths' understanding should differ from those concerning adults.

• YAKHAK HOEJI
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• v.41 no.3
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• pp.381-388
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• 1997

Metabolism of DWP401, recombinant juman epidermal growth factor, was examined in vivo and in vitro in rats. When $^{125}I$-labeled DWP401 was administered at a dose of 50 ${\mu}g$/kg by i.v. injection. $^{125}I$-labeled DWP401 was rapidly degraded within 30 minytes above 93%. Thin layer chromatography analysis of urine collected for 24 hr after i.v. administration of $^{125}I$-labeled DWP401 showed ohly one spot on a X-ray film which was considered as diiodo-tyrosine. This result suggests tha $^{125}I$-labeled DWP401 was completely digested into free amino acids without any specific intermediate polypeptides. About 42.1% of the administered iodine was recovered in 24 hr. For in vitro degradation study, $^{125}I$-labeled DWP401 was added to plama and tissue homogenates of rats and incubated at $37^{\circ}C$. Almost 98% of the added radioactivity recovered from the protein fraction of the liver, kidey, small intestine, stomach and spleen decreased rapidly. For examplem the recovery rates of $^{125}I$-labeled DWP401 were 58.6, 63.2, 39.9, 52.9 and 66.8% after 4hrs of incubation in respective organ homogenates.

• Nuclear Engineering and Technology
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• v.19 no.2
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• pp.107-114
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• 1987

Using a solution of $^{137}$ Cs as a tracer, radioactivity of a $^{137}$ Cs solution is measured by coincidence and anticoincidence counting methods. Sample sources in this study are fabricated by mixing $^{137}$ Cs with tracer, and the mixing ratios are 1/3 and 1/5, respectively in coincidence and anticoincidence methods. Specific activities of a $^{137}$ Cs solution are calculated by means of f-channel low energy threshold level variation and efficiency extrapolation. The results obtained by coincidence and anticoincidence counting methods are 552.78 kBq/g and 554.32kBq/g, respectively on the reference date and the combined uncertainties are 1.60kBq/g and 1.51kBq/g for each method. These two results show a good agreement within the uncertainty range.

• Journal of radiological science and technology
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• v.44 no.5
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• pp.481-487
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• 2021

This study was conducted for the purpose of efficient radioactive waste disposal and management. Experiment was evaluated the decontamination efficiencies of the four types decontamination materials(Water, Alcohol, Decontamination Water, Decontamination Gel) with radioactive wastes generated during radio-pharmaceutical production process at Korea Institute Radiological and Medical Sciences(KIRAMS). The radioactive waste sample used in experiment is a lead plate of the fume hood that was disposed in April, 2019. In the experimental method, radioactive waste was measured before and after decontamination using a HPGe semiconductor detector and Gamma survey meter. The measured values before and after decontamination were evaluated for decontamination efficiency as a percentage. As a result, it was confirmed that a lot of specific activity and surface dose rate was removed from the radioactive wastes. In particular, when decontamination water was used, most of the radioactivity of radioactive wastes was removed. Considering these results, if decontamination water is used in decontamination of radioactive waste, decontamination efficiency equivalent to the disposition criteria can be expected with just one decontamination treatment. In addition, in the case of water and alcohol, only on decontamination was effective in approximately 75% and 95%. Otherwise, when decontamination gel was used, it was confirmed that the largest deviation occurred among all experimental results.

• Journal of Radiation Industry
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• v.12 no.4
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• pp.355-363
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• 2018

A novel $N_3S_1$ chelate, Pro-Lys-Cys (PKC) to cyclic RGD to radiolabel with $^{99m}Tc$ was conjugated in an effort to decrease the high intestinal accumulation observed for $^{99m}Tc$-labeled PGC-RGD. The target specificity of the resulting PKC-RGD was similar to that of PGC-RGD as determined by a cell binding assay and a competition binding assay. The $^{99m}Tc$ radiolabeling of PKC-RGD resulted in radiochemical yields of 98% under mild conditions at high specific activities. Biodistribution data in normal mice clearly showed a significant decrease in intestinal uptake at 2 h postinjection for the $^{99m}Tc-PKC-c$ (RGDyK) compared to the $^{99m}Tc-GC-c$ (RGDyK) (from $19.65%ID{\cdot}g^{-1}$ to $7.31%ID{\cdot}g^{-1}$ for the GI tract). The $^{99m}Tc-PKC-c$ (RGDyK) biodistribution was also shown by a higher retention of radioactivity in the whole body, but with kidney accumulation over 8-fold higher than observed with $^{99m}Tc-PGC-c$ (RGDyK) at 2 h ($12.62%ID{\cdot}g^{-1}$ for PKC-RGD and $1.54%ID{\cdot}g^{-1}$ for PGC-RGD, respectively). These results show that the biodistribution may be altered especially concerning lipophilicity resulting in renal rather than hepatobiliary excretion. This comparative study made it possible to explore the effects of lipophilicity on the biodistribution of $^{99m}Tc$-labeled c (RGDyK) through the use of different tripeptide $N_3S_1$ chelators. Therefore, $^{99m}Tc-PKC-c$ (RGDyK) may be an attractive alternative for the in vivo imaging of integrin receptors.

• Journal of Radiopharmaceuticals and Molecular Probes
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• v.8 no.2
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• pp.71-76
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• 2022

Indigenous diagnostic dose of ¹³¹I-labeled meta-iodobenzylguanidine ([¹³¹I]mIBG) was prepared via Cu⁺ catalyzed isotope exchange reaction generated in situ by sodium metabisulfite for imaging of neuroblastoma tumor. [¹³¹I]mIBG was produced in overall 85-90% radiochemical yield. The average amount of radioactivity of [¹³¹I]mIBG was 2164 MBq (1998-2331MBq) with an average specific activity > 1000 MBq/mg at the end of synthesis. The radiochemical purity was ≥ 99.9% after purification through Dowex-1 × 8 ion exchange resin (100-150 mesh) at the date of preparation. The stability of [¹³¹I]mIBG at concentration 480-555 MBq/mL was > 97% at 4 ℃ after 4 days. The room temperature (25 ℃) stability of [¹³¹I]mIBG was > 98% after 24 h. Biodistribution of [¹³¹I]mIBG in patient showed uptake in salivary glands, liver, spleen and excreted though urinary bladder. Neuroendocrine medicated uptake into tumor lesion and metastatic sites were noted which strongly correlate with the morphological abnormalities of patient.

• The Korean Journal of Nuclear Medicine Technology
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• v.13 no.3
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• pp.92-101
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• 2009

Purpose: Scintimammography is one of the screening tests for the early diagnosis of breast cancer. It has been widely accepted as very useful in assessing masses that have not been detected in breast scanning. This method is highly sensitive and specific with respect to the diagnosis of primary and relapsing breast cancer. It has some difficulties, however, in detecting tumors sized 1 cm and below due to the radioactivity around the breast and the geometrical structure of the equipment. The recent introduction of high-resolution Breast-specific Gamma Imaging (BSGI) has made it possible to more accurately discriminate between malignant and benign tumors than with any other test method. Thus, the possibility of an unnecessary biopsy being performed has decreased. The purpose of this study was to examine the diagnostic capacity of mammography, breast sonography, and scintimammography, which are used for the early diagnosis of known breast cancer, and of BSGI, and to evaluate the skillfulness of radiologists. Materials and Methods: The 53 volunteers participants who had no clinical manifestation of breast cancer underwent the BSGI in February 2009. In the BSGI procedure, scanning images were obtained from the craniocaudal projection (CC) and the mediolateral Oblique projection (MLO), as well as from the additional $80{\times}80$-matrix-sized views at various angles in the Present Time method, 10 minutes after the 25 mCi $^{99m}Tc$-MIBI was injected. Results: The results of the BSGI showed that two participants had masses in their breast tissue. As the results of the diagnosis of four participants were not clear, they were retested and the results of the second test were negative. The results of the clinical screening test for breast cancer showed that the sensitivity of BSGI, scintimammography, mammography, and breast sonography was 86.5%, 77.8%, 85~90%, and 66.7%, respectively, and that their specificity was 92.4%, 84.2%, 20~42%, and 68%, respectively. Conclusion: The autodiagnosis and breast cancer screening test are needed for the early diagnosis of breast cancer. It was not easy, however, to accurately determine the presence of a mass in the breast using the existing breast cancer screening test. The patients with unclear test findings were made to undergo a histologic biopsy for a more accurate diagnosis. It is expected that the BSGI can provide useful information for the early diagnosis of breast cancer and of primary breast cancer, and will reduce the performance of unnecessary biopsies because of its higher sensitivity and specificity than existing breast cancer screening tests.

• Journal of Radiation Protection and Research
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• v.18 no.1
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• pp.9-24
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• 1993

The time-dependent radioecological model applicable to Korean environment has been developed in order to assess the radiological consequences following the short-term deposition of radionuclides in an accident of nuclear power plant. Time-dependent radioactivity concentrations in foodstuffs can be estimated by the model called 'KORFOOD' as well as time-dependent and time-integrated ingestion doses. Three kinds of critical radionuclides and thirteen kinds of foodstuffs were considered in this model. Dynamic variation of radioactivities were simulated by considering several effects such as deposition, weathering and washout, resuspension, root uptake, translocation, leaching, senescence, intake and excretion of soil by animals, intake and excretion of feedstuffs by animals, etc. The input data to the KORFOOD are the time of the year when the deposition occurs, the kinds of radionuclides and foodstuffs for estimation. The time-dependent specific activities in rice and the ingestion doses due to the consumption of all considered foodstuffs were calculated with deposition time using agricultural data-base in Kori region. In order to validate results of KORFOOD, the calculated results were compared with those by a leading German model, ECOSYS-87. The comparison of results shows good agreements within a factor of ten.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.14 no.3
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• pp.253-266
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• 2016

In accordance with the classification system of radioactive waste in Korea, all the disused sealed radioactive sources (DSRSs) fall under the category of EW, VLLW or LILW, and should be managed in compliance with the restrictions for the disposal method. In this study, the management and disposal method are drawn in consideration of half-life of radionuclides contained in the source and A/D value (i.e. the activity A of the source dividing by the D value for the relevant radionuclide, which is used to provide an initial ranking of relative risk for sources) in addition to the domestic classification scheme and disposal method, based on the characteristic analysis and review results of the management practices in IAEA and foreign countries. For all the DSRSs that are being stored (as of March 2015) in the centralized temporary disposal facility for radioisotope wastes, applicability of the derivation result is confirmed through performing the characteristic analysis and case studies for assessing quantity and volume of DSRSs to be managed by each method. However, the methodology derived from this study is not applicable to the following sources; i) DSRSs without information on the radioactivity, ii) DSRSs that are not possible to calculate the specific activity and/or the source-specific A/D value. Accordingly, it is essential to identify the inherent characteristics for each of DSRSs prior to implementation of this management and disposal method.

• The Korean Journal of Nuclear Medicine
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• v.34 no.3
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• pp.243-251
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• 2000

Purpose: This prospective study was performed to evaluate the usefulness of preoperative radioimmunoscintigraphy and intraoperative scintimetric examination (radioimmunoguided surgery: RIGS) using $^{99m}Tc-anti-CEA\;F(ab')_2$ fragment. Materials and Methods: Nineteen patients with rectal cancer underwent preoperative whole body planar scintigraphy at 4 hours after injection of $^{99m}Tc-anti-CEA\;F(ab')_2$ fragment and SPECT imaging at 18 hours. Surgical operation was performed at 24 hours after injection. During laparotomy, radioactivities from intraabdominal viscera were measured by gamma probe. The radioactivities from excised tumor and lymph nodes were also measured and compared with pathology. Results: All nineteen patients were confirmed to have adenocarcinomas in the rectum. Twenty-seven of 97 excised lymph node groups had metastasis and 2 patients had liver metastasis in pathology Preoperative radioimmunoscintigraphy detected primary tumors in 11 patients (sensitivity 55%) and it could not detect any lymph nodes or liver metastasis. All patients showed high radioactivity in the kidneys, liver, spleen, and major vessels in intraoperative measurement by gamma probe, and tumor activity was not discriminated from background activity However, radioactivity from excised tumor was higher than normal rectum (T/B ratio; $3.47{\pm}2.25$). When excised lymph node activity/background activity ratio >1.5 was considered as positive criteria of metastasis, sensitivity, specificity, positive and negative predictive values were 78.6%, 73.9%, 55.0% and 89.5%, respectively. Conclusion: Radioimmunoscintigraphy using $^{99m}Tc-anti-CEA\;F(ab')_2$ has no additional value for preoperative staging and use of early RIGS using $^{99m}Tc-anti-CEA\;F(ab')_2$ is inappropriate. For early RIGS using $^{99m}Tc$ labeled antibodies in rectal cancer patients, further development of more specific antibodies and methods to reduce background activity are needed.