• The Korean Journal of Nuclear Medicine Technology
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• v.13 no.3
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• pp.48-55
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• 2009

Purpose: As Korean nuclear law doesn't have any clear guideline about the dose and the external dose rate(uSv/h) requiring hospitalization in radioactive iodine treated patients, the patients are discharged when they meet the guideline of IAEA Basic Safety Standards(BSS). We measured external dose rate(${\mu}Sv/h$) of inpatient underwent 3700MBq (100 mCi) $^{131}I$ radioiodine treatment and considering external dose rate(${\mu}Sv/h$), residual activity(mCi) and excretion rate(%) we found the time for RA to be lowered from 3700MBq (100 mCi) to 1110 MBq (30 mCi) to give reference to set a guideline for discharge. Materials and Methods: Forty-two patients underwent thyroidectomy and scheduled for radioiodine treatment, who received 3700MBq (100 mCi) of $^{131}I$ orally and had no renal disease were examined. After 1, 2, 4, 8, and 20, 24, 40 hours iodine uptake and before/after the urination, the external dose rate(${\mu}Sv/h$) measured using FH40G-L(Thermo Fisher Scientific Inc., MA) at a distance and a height of 1 m for 20 sec on the average. Results and Conclusions: At 20 hours, the external dose rate was decreased to $49{\pm}13\;{\mu}Sv$/h, namely, 78% of administrated radioactivity was excreted and 814 MBq (30 mCi) was residual, and it met the accepted limit for discharge of (IAEA, BSS) under 1110 MBq (30 mCi) (1 m at 66 uSv/h).

• Progress in Medical Physics
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• v.27 no.3
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• pp.156-161
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• 2016

When air discharged from a radioisotope production facility is contaminated with radiation, the public may be exposed to radiation. The objective of this study is to manage such radiation exposure. We measured the airborne radioactivity concentration at a 30 MeV cyclotron radioisotope production facility to assess whether the exhaust gas was contaminated. Additionally, we investigted the radioactive contamination of the air filter for efficient air purification and radiation safety control. To measure the airborne radiation concentration, specimens were collected weekly for 4 h after the beginning of the radioisotope production. Regarding the air purifier, five specimens were collected at different positions of each filter-pre-filter, high-efficiency particulate air filter, and charcoal filter-installed in the cyclotron production room. The concentrations of F-18, I-123, I-131, and Tl-201 generated in the radioiodine production room were $13.5Bq/m^3$, $27.0Bq/m^3$, $0.10Bq/m^3$, and $11.5Bq/m^3$, respectively; the concentrations of F-18, I-123, and I-131 produced in the radioisotope production room were $0.05Bq/m^3$, $16.1Bq/m^3$, and $0.45Bq/m^3$, correspondingly; and those of F-18, I-123, I-131, and Tl-201 generated in the accelerator room were $2.07Bq/m^3$, $53.0Bq/m^3$, $0.37Bq/m^3$, and $0.15Bq/m^3$, respectively. The maximum radiation concentration of I-123 generated in the radioiodine production room was 1,820 Bq/g, which can be disposed after 2 days. The maximum radiation concentration of Tl-202 generated in the radioisotope production room was 205 Bq/g, and this isotope must be stored for 53 days. The I-123 generated in the radioiodine production room had a maximum concentration of 1,530 Bq/g and must be stored for 2 days. The maximum radiation concentration of Na-22 generated in the radioisotope production room was 0.18 Bq/g and this isotope must be disposed after 827 days. To manage the exhaust, the efficiency of air purification must be enhanced by selecting an air purifier with a long life and determining the appropriate replacement time by examining the differential pressure through systematic measurements of the airborne radiation contamination level.

• 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.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.5 no.4
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• pp.267-272
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• 2007

Various kinds of RI wastes are discharged from licensed organizations of radioisotopes les such as hospitals and clinic organizations, educational organizations, research institutions, and public organizations. Radioiodines such as $^{125}I\;and\;^{131}I$ are radioisotopes mainly used in nuclear medicine and industry. A method for the determination of radioiodines in RI wastes has been applied to measure low level activity using acid decomposition method and HPGe gamma ray spectrometer. Prior to analysis of real samples, $^{131}I$ reference solution and 10 g of yellow tissue paper was added to flask in mantle and was heated in 100 mL of 0.4 N $K_2Cr_2O_7$ and 100 mL of 9 M $H_2SO_4$, and then distilled after adding 10 mL of 30% $H_2PO_3$ and 1 mL of 30% $H_2O_2$. The condensed iodine by circulator was extracted into $CCl_4$, then back-extracted into the aqueous phase with 10 mL of 5% $K_2SO_2$ solution. Finally, $^{131}I$ was measured at 364.48 keV using HPGe gamma ray spectrometer after precipitation and filtration. Chemical yield of three steps such as acid decomposition process, chemical separation process, and precipitation and filtration process was more han 94% respectively, MDA(Minimum Detectable Activity) of $^{131}I$ at this analytical condition was 0.6 Bq/g.

• The Korean Journal of Nuclear Medicine
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• v.27 no.1
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• pp.112-117
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• 1993

Background Radioiodine ($^{131}I$), a major component of nuclear fallout and a valuable therapeutic agent for thyrotoxicosis and thyroid cancer, has been regarded as a mutagen or a carcinogen without any convincing evidence. To evaluate the genotoxicity of radioiodine ($^{131}I$) we performed a micronuclei test in mice bone marrow. Materials and methods : Mice (ICR strain, $25{\sim}30 g$) were divided to 4 groups: control, group 1 (0.17 mCi/kg, usual therapeutic dose for thyrotoxicosis), group 2 (1.67 mCi/kg, usual therapeutic dose for thyroid cancer), and group 3 (16.67 mCi/kg, usual accumulated dose causing bone marrow suppression). $^{131}I$ was administered intraperitoneally. Ten mice of each group were sacrificed at days 1 and 3. Bone marrow were smeared and stained with May-Grunwald Giemsa method. One thou-sand polychromatic erythrocytes (PCE) and normochromatic erythrocytes (NCE) were counted under the light microscope, and the number of micronucleated PCEs were recorded. Results : The frequency of micronuclei in PCE (and NCE in parenthesis) in the control group was $0.25{\pm}0.07$ ($0.23{\pm}0.07$)% in day 1 and $0.24{\pm}0.07$ ($0.21{\pm}0.07$)% in day 3. Those in group 1 was $0.27{\pm}0.1$ ($0.23{\pm}0.09$)% in day 1 and $0.28{\pm}0.07$ ($0.25{\pm}0.06$)% in day 3. Micronuclei was noted in $0.29{\pm}0.08$ ($0.26{\pm}0.09$)% in day 1 and $0.31{\pm}0.05$ ($0.29{\pm}0.06$)% in day 3 in group 2, and in $0.32{\pm}0.06$ ($0.25{\pm}0.09$)% in day 1 and $0.33{\pm}0.08$ ($0.3{\pm}0.06$)% in day 3 in group 3. There was no difference in the frequency of micronuclei between each groups (p> 0.05). Conclusion : Radioiodine ($^{131}I$) did not cause any genotoxicity in mice bone marrow even at the large dose (16.67 mCi/kg).

• Journal of Radiation Protection and Research
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• v.45 no.1
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• pp.2-10
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• 2020

Background: Huge amounts of radionuclides were released into the environment due to the Fukushima Daiichi Nuclear Power Plant (FDNPP) accident, which caused not only serious contamination on the ground, but also radiation exposure to the public. One problem that remains in performing the dose estimation is the difficulty of estimating the internal thyroid dose due to the intake of radioiodine (mainly, ¹³¹I) because of limitations to the human data available. Materials and Methods: The relevant papers were collected and reviewed by the authors. The results of thyroid dose estimates from different studies were tabulated for comparison. Results and Discussion: The thyroid dose estimates from the studies varied widely. The dose estimates by the United Nations Scientific Committee on the Effects of Atomic Radiation were higher than the others due to the ingestion dose being based on conservative assumptions. The dose estimates by Japanese experts were mostly below 20-30 mSv. The recent studies suggested that exposure on March 12, 2011 would be crucial for late evacuees from the areas near the FD-NPP because of the possible intake of short-lived radionuclides other than ¹³¹I. Further multilateral studies are vital to reduce uncertainties in the present dose estimations. Conclusion: The estimation of the thyroid doses to Fukushima residents still has many uncertainties. However, it is considered unlikely that the thyroid doses exceeded 50 mSv except in some extreme cases. Further multilateral studies are thus necessary to reduce the uncertainties in the present dose estimations.

• The Korean Journal of Nuclear Medicine
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• v.34 no.2
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• pp.107-118
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• 2000

Purpose: To evaluate the effectiveness of radioiodine treatment for metastatic thyroid carcinoma, we reviewed results of radioactive iodine treatment in patients with functional lung or bone metastases. Materials and Methods: Of 760 patients who were treated for differentiated thyroid cancer between 1984 and 1998, we detected pulmonary metastases and bone metastases in 76 patients (10.0%) and 20 patients (2.6%), respectively. Among them, we could evaluate the effectiveness of I-131 therapy in 53 patients with lung metastases and 15 patients with bone metastases. Results: Of 53 patients who received I-131 therapy with a mean cumulative dose of 26.2 GBq (1.1-84.4 GBq) for pulmonary metastases, metastatic lung lesions completely resolved in 19 patients (35.8%) and improved in 22 patients (41.5%). In 13 of 19 patients with complete remission of pulmonary metastases, the total accumulated dose of I-131 was less than 18.5 GBq. We found 43 sites of metastatic bone lesions in 15 patients with bone metastases. Of 29 lesions which received I-131 therapy, metastatic lesions improved in 14 sites (48.3%), but did not change or progress in 15 sites (51.7%) despite the I-131 therapy. Three lesions were completely cured with a combination treatment of surgery(${\pm}$ external radiotherapy) and I-131 therapy, and the other 11 lesions improved. Conclusion: Radioactive iodine treatment gives favorable results for pulmonary metastases. However, for bone metastases, there might be a need to use combination therapy including I-131 and surgery or external irradiation.

• Nuclear Medicine and Molecular Imaging
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• v.42 no.5
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• pp.383-393
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• 2008

Purpose: Cancer specific killing can be achieved by therapeutic gene activated by cancer specific promotor. Expression of sodium iodide symporter (NIS) gene causes transportation and concentration of iodide into the cell, therefore radioiodine treatment after NIS gene transfer to cancer cell could be a form of radionuclide gene therapy. luciferase (Luc) gene transfected cancer cell can be monitored by in vivo optical imaging after D-luciferin injection. Aims of the study are to make vector with both therapeutic NIS gene driven by AFP promoter and reporter Luc gene driven by CMV promoter, to perform hepatocellular carcinoma specific radiodiodine gene therapy by the vector, and assessment of the therapy effect by optical imaging using luciferase expression. Materials and Methods: A Vector with AFP promoter driven NIS gene and CMV promoter driven Luc gene (AFP-NIS-CMV-Luc) was constructed. Liver cancer cell (HepG2, Huh-7) and non liver cancer cell (HCT-15) were transfected with the vector using liposome. Expression of the NIS gene at mRNA level was elucidated by RT-PCR. Radioiodide uptake, perchlorate blockade, and washout tests were performed and bioluminescence also measured by luminometer in these cells. In vitro clonogenic assay with 1-131 was performed. In vivo nuclear imaging was obtained with gamma camera after 1-131 intraperitoneal injection. Results: A Vector with AFP-NIS-CMV-Luc was constructed and successfully transfected into HepG2, Huh-7 and HCT-15 cells. HepG2 and Huh-7 cells with AFP-NIS-CMV-Luc gene showed higher iodide uptake than non transfected cells and the higher iodide uptake was totally blocked by addition of perchlorate. HCT-15 cell did not showed any change of iodide uptake by the gene transfection. Transfected cells had higher light output than control cells. In vitro clonogenic assay, transfected HepG2 and Huh-7 cells showed lower colony count than non transfected HepG2 and Huh-7 cells, but transfected HCT-15 cell did not showed any difference than non transfected HCT-15 cell. Number of Huh-7 cells with AFP-NIS-CMV-Luc gene transfection was positively correlated with radioidine accumulation and luciferase activity. In vivo nuclear imaging with 1-131 was successful in AFP-NIS-CMV-Luc gene transfected Huh-7 cell xenograft on nude mouse. Conclusion: A Vector with AFP promoter driven NIS and CMV promoter driven Luc gene was constructed. Transfection of the vector showed liver cancer cell specific enhancement of 1-131 cytotoxicity by AFP promoter, and the effect of the radioiodine therapy can be successfully assessed by non-invasive luminescence measurement.

• Korean Journal of Head & Neck Oncology
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• v.15 no.1
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• pp.46-51
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• 1999

Background: Total thyroidectomy and postoperative radiodiodine ablation therapy in differentiated thyroid carcinomas enhance the reliability of serum thyroglobulin(Tg) levels and radioiodine scan in detecting recurrence or distant metastasis. There have been, however, some limitations in using these methods under certain conditions. Recently, several reports have indicated that thyroid peroxidase(TPO) could be used as an alternative tumor marker. We aimed to estimate the significance of serum TPO levels in differentiated thyroid carcinoma. Materials and Methods: Forty-eight patients who had undergone total thyroidectomy due to papillary thyroid carcinomas and who had been followed-up for at least 3 years were classified into two groups: 27 patients without any evidence of recurrence in group 1; and 20 patients with recurrence or distant metastasis in group 2. All patients were examined by radioiodine scans. Serum Tg, TSH, antithyroglobulin antibody, and TPO were measured and the relationships were statistically analyzed. The sensitivity and specificity of $^{131}I$ scan, serum Tg, and serum TPO were evaluated. Results: Serum Tg levels were $3.81{\pm}5.16ng/mL$ in group 1 and $147.02{\pm}193.75ng/mL$ in group 2. Only 2 patients in group 1 showed Tg levels exceeding 10ng/mL. In contrast, 4 patients in group 2 were under 10ng/mL. Serum antithyroglobulin antibody and TSH levels showed no statistical difference between the two groups. In group 1, 16 patients showed negative serum TPO results, and 4 patients in group 2 showed negative results. There was no correlation among serum Tg levels, antithyroglobulin antibody titers, and serum TPO levels in each group. In group 2, 4 patients with negative serum Tg levels showed positive TPO results and positive whole body scans. Two cases with false negative $^{131}I$ scans showed positive serum TPO and Tg results. In 4 cases showing false negative serum TPO levels, serum Tg levels and $^{131}I$ scans were positive. Conclusion: Serum Tg levels, radioiodine scans, and serum TPO levels can be clinically used as complementary methods in the diagnosis of recurrent or metastatic thyroid carcinomas. Serum TPO levels may be helpful when other methods fail to detect recurrences or distant metastasis in highly suspected patients.

• The Korean Journal of Nuclear Medicine
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• v.6 no.1
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• pp.41-49
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• 1972

The author observed the thyroid $^{131}I$ uptake rate using an intradermal injection method. The amount of activity remaining at the site of intradermal injection of 0.1 ml. of $5{\mu}Ci.\;of\;^{131}I$ in physiologic saline was measured in 79 cases of hyperthyroidism and in 24 cases of hypothyroidism. The cases had been confirmed by clinical and laboratory findings, at the department of medicine, (radioisotope clinic) Pusan National University Hospital. Twenty-nine normal control cases were examined currently by the same technique during the period from Jan. 1967 to June 1970. The following results were obtained: 1. In the normal group, the ranges and mean values of the thyroid uptake 10, 15, 20, 25, 30 and 60 minutes after intradermal $^{131}I$ injection, were $0{\sim}10%(6.33{\pm}1.63),\;0{\sim}15%(7.83{\pm}2.12),\;0{\sim}15%(8.46{\pm}2.82),\;5.1{\sim}20%(9.66{\pm}2.27),\;5.1{\sim}25%(10.47{\pm}2.52),\;5.1{\sim}30%(13.03{\pm}4.42)$. 2. In the hyperthyroid group, the ranges and mean values of the thyroid uptake 10, 15, 20, 25, 30 and 60 minutes after intradermal $^{131}I$ injection were $5.1{\sim}45%(22.25{\pm}7.04),\;10.1{\sim}50%(28.32{\pm}6.67),\;15.1{\sim}55%(34.78{\pm}11.63),\;15.1{\sim}65%(37.95{\pm}7.72),\;20.1{\sim}65%(41.49{\pm}0.05)\;and\;20.18096(48.71{\pm}12.51)$. 3. In the hypothyroid group, he ranges of thyroid $^{131}I$ uptake by intradermal $^{131}I$ injection at 10, 15, 20, 25, 30 and 60 minutes lay between 0 and 10%, and the the mean values were $4.23{\pm}1.76,\;5.08{\pm}1.68,\;5.56{\pm}1.70,\;6.02{\pm}1.75,\;6.37{\pm}1.91\;and\;6.95{\pm}2.07$. 4. In conclusion, thyroid function test using an intradermal injection method in cases of hyperthyroidism, showed characteristic values which seemed to be of diagnostic significance.