• Tuberculosis and Respiratory Diseases
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• v.66 no.1
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• pp.13-19
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• 2009

Background: The interferon-gamma assay is reported to have high sensitivity and specificity for making the diagnosis of latent tuberculosis infection. The clinical usefulness of this essay for detecting active tuberculosis has not fully defined. We evaluated the diagnostic value of the commercial interferon-gamma assay kit (QuantiFERONTB GOLD) for patients with suspected tuberculosis. Methods: From January to August 2007, we recruited 52 patients with suspected tuberculosis infection. We performed chest X-ray, sputum smear, culture, PCR and the QuantiFERON-TB GOLD test. Pleural fluid analysis and pleural biopsy were also done for the patients with pleural effusion. Results: Of the 52 patients we studied, 30 patients had a positive QuantiFERON-TB GOLD test result. 35 patients were finally diagnosed with active tuberculosis: twenty-five with a positive QuantiFERON-TB GOLD test and 10 with a negative QuantiFERON-TB GOLD test. The sensitivity of the QuantiFERON-TB GOLD test was 71.4% and the specificity was 64.7%. The positive predictive value was 0.83 and the negative predictive value was 0.50. There was no significant difference of any of the clinical and laboratory characteristics between the two groups of patients except the C-reactive protein (CRP) level. The CRP level was 29.2${\pm}$27.3 mg/dL in the pulmonary tuberculosis patients with a positive QuantiFERON-TB GOLD test and 72.9${\pm}$67.9 mg/dL in the patients with a negative QuantiFERON-TB GOLD test (p<0.05). Conclusion: The sensitivity and specificity of the QuantiFERON-TB GOLD test were inadequate for making the diagnosis of active tuberculosis. We suggest that the QuantiFERON-TB GOLD test should not be used by itself to exclude the diagnosis of active tuberculosis. The relationship of the QuantiFERON-TB GOLD test and the CRP level in patients with TB would be further investigated.

• The Korean Journal of Nuclear Medicine Technology
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• v.15 no.1
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• pp.70-74
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• 2011

Purpose: In the Nuclear Medicine department of Asan Medical Center, radioactive waste has been disposed of by using several disposal boxes designed for nuclear waste. However, some quantity of radioactivity has been detected occasionally due to some radiologists' carelessness not only from radioactive waste, but also from medical waste such as uncontrolled radioactive waste related to patients, poly gloves or saline solution bottles from radiopharmaceuticals laboratory. Thus, this study is going to suggest a solution to maintain the medical wastes made from controlled areas that can be below maximum permissible surface dose limits by finding the cause of radioactive contamination. Materials and methods: This study was taken place in 17 different places-2 medical wastebaskets in the waiting room, 2 medical wastebaskets in the PET room, 5 medical wastebaskets in the in vitro laboratory and 6 medical wastebaskets in the radiopharmaceuticals laboratory of the East building, 2 medical wastebaskets in the waiting room of the New building of Nuclear Medicine Department in Asan Medical Center from April to August 2010. Mean radioactivity and its standard deviation of each place have been found by measuring surface contamination of medical wastebaskets and backgrounds twice a week, totaling 30 times. An independent t-test of SPSS (Ver. 12.0) statistic program has been used for statistical analysis. Swabs, saline solution bottles and poly gloves collected from each place also measured 30 times, respectively. Results: This study analyzed medical waste and the backgrounds of each place by using survey meter detectors that significant differences of five places did not exist, but existed statistically in twelve places (p<0.05). Also, swabs, saline solution bottles and poly gloves collected from each radioactive waste partly exceed the legal dose limit as a result of measuring by a gamma counter. Conclusion: Backgrounds and the surface doses of radioactive disposal box in all 17 places measured by the survey meter did not exceed the legal dose limit; however, it obviously showed that there were prominent differences in 12 places. Assuming that the cause of the differences was swabs, saline solution bottles and gloves, we examined them by gamma counter, and the results showed remarkably high doses of radioactivity. Consequently, swabs and poly gloves which are normally disposed in the general medical waste box should be disposed in the radioactive waste box furnished by radiopharmaceuticals laboratory. Also, saline solution discharged from radioactive pharmaceutical places is considered as radioactive liquid waste so that it should be disposed of by the septic tank specifically designed for radioactive liquid.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.14 no.4
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• pp.343-356
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• 2016

The Korea Radioactive Waste Agency (KORAD) has developed a dual-purpose metal cask for the dry storage of spent nuclear fuel that has been generated by domestic light-water reactors. The metal cask was designed in compliance with international and domestic technology standards, and safety was the most important consideration in developing the design. It was designed to maintain its integrity for 50 years in terms of major safety factors. The metal cask ensures the minimization of waste generated by maintenance activities during the storage period as well as the safe management of the waste. An activation evaluation of the main body, which includes internal and external components of metal casks whose design lifetime has expired, provides quantitative data on their radioactive inventory. The radioactive inventory of the main body and the components of the metal cask were calculated by applying the MCNP5 ORIGEN-2 evaluation system and by considering each component's chemical composition, neutron flux distribution, and reaction rate, as well as the duration of neutron irradiation during the storage period. The evaluation results revealed that 10 years after the end of the cask's design life, $^{60}Co$ had greater radioactivity than other nuclides among the metal materials. In the case of the neutron shield, nuclides that emit high-energy gamma rays such as $^{28}Al$ and $^{24}Na$ had greater radioactivity immediately after the design lifetime. However, their radioactivity level became negligible after six months due to their short half-life. The surface exposure dose rates of the canister and the main body of the metal cask from which the spent nuclear fuel had been removed with expiration of the design lifetime were determined to be at very low levels, and the radiation exposure doses to which radiation workers were subjected during the decommissioning process appeared to be at insignificant levels. The evaluations of this study strongly suggest that the nuclide inventory of a spent nuclear fuel metal cask can be utilized as basic data when decommissioning of a metal cask is planned, for example, for the development of a decommissioning plan, the determination of a decommissioning method, the estimation of radiation exposure to workers engaged in decommissioning operations, the management/reuse of radioactive wastes, etc.

• The Korean Journal of Nuclear Medicine
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• v.28 no.1
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• pp.124-132
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• 1994

Radioactive iodine has been widely used in patients with thyroid cancer combined with surgical treatment. However, due to individual variations in absorption and excretion and uptake by tumor tissue of radioactive iodine, there are differences in therapeutic effect and adverse effects even if the same doses are administrated. So this study compared the therapeutic effect and radiation hazard by measuring internal radiation dose. Of total 27 patients with well differentiated thyroid cancer who had been thyroidectomized, we administered radioactive iodine 100 mCi, 150 mCi, 200 mCi. According to BEL DOSIMETRY PROTO-COL, beta and gamma ray dose were estimated from a pelt of the logarithm of the percent of dose per liter of whole blood versus day, and percent dose retained versus day using somilogarithmic paper, respectively. 1) Physical dose to whole blood averaged $56.54{\pm}13.02$ rad in 100 mCi administered group, $76.83{\pm}19.97$ rad in 150 mCi administered group, $95.08{\pm}25.51$ rad in 200 mCi administered group and there has been a significant correlation among the groups. 2) Mean percent dose retained 48 hours later was 26.34%. 3) There was no significant correlation of physical dose between absence and presence of metastasis. 4) 17 of 19 patients who has been followed up with TSH and serum throglobulin, Thallium scan were successfully ablated by radioactive iodine. 5) Leukocyte, lymphocyte, neutrophil, platelet counts all deelined in 4.6 weeks and most of all were restored 3 months later. 6) There was no significant correlation between physical dosimetry and biologic dosimetry. Generally administered doses of radioactive iodine (100-200 mCi) to patients with thyroid cancer postoperatively had developed transient bone marrow suppression and minimal chromosomal aberration, but they were within safety dose to blood (200 rad). And there has been no significant differences in residual dose 48 hours later between Korean and western people.

• The Korean Journal of Nuclear Medicine
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• v.31 no.3
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• pp.320-329
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• 1997

Neuroanatomic substrate of autism has been the subjects of continuing investigation. Because previous studies had not demonstrated consistent and specific neuroimaging findings in autism and most studies comprised adults and school-aged children, we performed a retrospective review in search of common functional and anatomical abnormalities with brain SPECT using Tc-99m ECD and correlative MRI The patient population was composed of 18 children aged 28 to 89 months(mean age : 55 months) who met the diagnostic criteria of autism as defined in the DSM-IV and CARS. Brain SPECT was performed after intravenous injection of 185-370MBq of Tc-99m ECD using brain dedicated annular crystal gamma camera. MRI was performed in all patients including T1, T2 axial and T1 sagittal sequences. SPECT data were visually assessed. Thirteen patients had abnormal SPECT scan revealing focal areas of decreased perfusion. Decreased perfusion of cerebellar vermis(12/18), cerebellar hemisphere(11/18), thalami(13/18), basal ganglia(4/18), posterior parietal(7/18), and temporal(4/18) area were noted on brain SPECT. Whereas, only 3 patients had abnormal MR findings which were subtle volume loss of parieto-occipital white matter in 3 and mild thinning of posterior body of corpus callosum in 2 and slightly decreased volume of cerebellar vermis in 1. Comparison of the numbers of abnormal findings revealed that regional cerebral blood flow (rCBF) abnormalities seen on SPECT were more numerous than anatomical abnormalities seen on MRI. In conclusion, extensive perfusion impairment involving cerebellum, thalami and parietal lobe were found in this study. SPECT may be more sensitive in reflecting pathophysiology of autism than MRI. However, further studies are mandatory to determine the significance of thalamic and parietal perfusion impairment in autism.

• The Korean Journal of Nuclear Medicine Technology
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• v.18 no.1
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• pp.3-9
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• 2014

Purpose: Our goals were to evaluate the effect of high dose radioiodine treatment for thyroid cancer by taking in laxatives. Materials and Methods: Twenty patients(M:F=13:7, age $46.3{\pm}8.1\;yrs$) who underwent high dose radioiodine treatment were seperated into Group 1 taking $^{131}I$ 5,500 MBq and Group 2 with the use of laxatives after taking $^{131}I$ 5,500 MBq. The whole body was scanned 16 hours and 40 hours after taking radioactive iodines by using gamma camera, the ROIs were drawn on the gastro-intestinal tract and thigh for calculation of reduction ratio. At particular time during hospitalization, the radioactivity remaining in the body was measured in 1 meter from patient by using survey meter (RadEye-G10, Thermo Fisher Scientific, USA). Schematic presentation of an Origin 8.5.1 software was used for spatial dose rate. Statistical comparison between groups were done using independent samples t-test. P value less than 0.05 was regarded as statistically significant. Results: The reduction ratio in gastro-intestinal 16 hours and 40 hours after taking laxatives is $42.1{\pm}6.3%$ in Group 1 and $72.1{\pm}6.4%$ in Group 2. The spatial dose rate measured when discharging from hospital was $23.8{\pm}6.7{\mu}Sv/h$ in Group 1 and $8.2{\pm}2.4{\mu}Sv/h$ in Group 2. The radioactivity remaining in the body is much decreased at the patient with laxatives(P<0.05). Conclusion: The use in combination with laxatives is helpful for decreasing radioactivity remaining in the body. The radioactive contamination could be decreased at marginal individuals from patients.

• Journal of Radiation Protection and Research
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• v.17 no.1
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• pp.21-30
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• 1992

The frequencies of KCCH cyclotron neutron (30 cGy/min) or $^{60}Co\;{\gamma}-rays$ (210 cGy/min)-induced asymmetrical interchanges (dicentrics and centric rings) and acentric fragments (deletion) at several doses were measured in the normal human peripheral blood lymphocytes Chromosome aberrations were scored at the first nitosis after stimulation with phytohemagglutinin. The neutron and y-ray data were analysed on linear, power-law, quadratic and linear-quadratic model . When the dicentrics and centric rings of ${\gamma}-rays$ datas were pooled and fitted to these model, good fits were obtained to power-law $[Y=(5.81{\pm}1.96){\times}10^6D^{1.93+0.06},\; P=0.931]$, quadratic $[Y=(3.91{\pm}0.09){\times}10^{-6}D^2,\;P=0.972]$ an linear-Quadrati model $[Y=(6.55{\pm}6.83){\times}10^{-5}D+(3.72{\pm}0.22){\times}10^{-6}D^2\; P=0.922]$, except for linear model (P=0.067) As in the case of neutron data, the best fit was obtained to the linear model $(Y=(6.12{\pm}0.17){\times}10^{-3}\;D-0.22,\;P=0.987]$ and good fits were obtained to power-law$[Y=(5.36{\pm}3.02) {\times}10^{-4}D^{1.42+0.11},\; P=0.601]$ and linear-quadratic model$[Y=(2.43{\pm}0.70){\times}10^{-3}D+(1.21{\pm}0.39){\times}10^{-7}D^2$, \;P=0.415], except for quadratic model (P<0.005). The relative biological effectiveness (RBE) of neutron compared with y-ray was estimated by best fitting model. In the asymmetrical interchanges range between 0.1 and 1.5 per cell, the RBE was found to be $2.714{\pm}0.408$.

• The Korean Journal of Nuclear Medicine
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• v.39 no.3
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• pp.191-199
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• 2005

Purpose: In order to obtain better quantitation of kidney uptake, this study is to evaluate a conjugate view method (CVM) using a geometric mean attenuation correction for kidney uptake and to compare it to Gate's method. Materials & Methods: We used a Monte Carlo code, SIMIND and a Zubal phantom, to simulate kidney uptake. SIMIND was both simulated with or without scatter for the Zubal phantom. Also, a real phantom test was carried out using a dual-head gamma camera. The activity of 0.5 mCi was infused into two small cylinder phantoms of 5 cm diameter, and then, they were inserted into a cylinder phantom of 20 cm diameter. The results by the CVM method were compared with ideal data without both of attenuation and scatter and with Gate's method. The CVM was performed with or without scatter correction. The Gate's method was performed without scatter correction and it was evaluated with regards to $0.12cm^{-1}\;and\;0.15cm^{-1}$ attenuation coefficients. Data were analyzed with comparisons of mean counts in the legions of interest (ROI), profiles drawn over kidney images and linear regression. Correlation coefficients were calculated with ideal data, as well. Results: In the case of the computer simulation, mean counts measured from ideal data, the CVM and the Gate's method were (right $998{\pm}209$, left: $896{\pm}249$), (right: $911{\pm}207$, left: $815{\pm}265$), and (right: $1065{\pm}267$, left: $1546{\pm}267$), respectively. The ideal data showed good correlation with the CVM and the correlation coefficients of the CVM, Gate's method were (right: 0.91, left: 0.93) and (right: 0.85, left: 0.90), respectively. Conclusion: The conjugate view method using geometric mean attenuation correction resulted in better accuracy than the Gate's method. In conclusion, the conjugate view method independent of renal depths may provide more accurate kidney uptake.

• The Korean Journal of Nuclear Medicine
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• v.36 no.6
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• pp.344-356
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• 2002

Purpose: RBC blood pool SPECT has been used to diagnose focal liver lesion such as hemangioma owing to its high specificity. However, low spatial resolution is a major limitation of this modality. Recently, ordered subset expectation maximization (OSEM) has been introduced to obtain tomographic images for clinical application. We compared this new modified iterative reconstruction method, OSEM with conventional filtered back projection (FBP) in imaging of liver hemangioma. Materials and Methods: Sixty four projection data were acquired using dual head gamma camera in 28 lesions of 24 patients with cavernous hemangioma of liver and these raw data were transferred to LINUX based personal computer. After the replacement of header file as interfile, OSEM was performed under various conditions of subsets (1,2,4,8,16, and 32) and iteration numbers (1,2,4,8, and 16) to obtain the best setting for liver imaging. The best condition for imaging in our investigation was considered to be 4 iterations and 16 subsets. After then, all the images were processed by both FBP and OSEM. Three experts reviewed these images without any information. Results: According to blind review of 28 lesions, OSEM images revealed at least same or better image quality than those of FBP in nearly all cases. Although there showed no significant difference in detection of large lesions more than 3 cm, 5 lesions with 1.5 to 3 cm in diameter were detected by OSEM only. However, both techniques failed to depict 4 cases of small lesions less than 1.5 cm. Conclusion: OSEM revealed better contrast and define in depiction of liver hemangioma as well as higher sensitivity in detection of small lesions. Furthermore this reconstruction method dose not require high performance computer system or long reconstruction time, therefore OSEM is supposed to be good method that can be applied to RBC blood pool SPECT for the diagnosis of liver hemangioma.

• Journal of Radiation Protection and Research
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• v.23 no.1
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• pp.7-15
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• 1998

In order to evaluate the effectiveness of some decontamination agents against skin contamination of $^{60}Co$ and $^{137}Cs$, the experiments were carried out in this study. In the experiments, pig skin was used instead of human skin , $^{60}CoC1_2$ and $^{137}CsCl$ were used the liquid sources of skin contamination. To examine the effectiveness of decontamination agents, skin decontamination was tried using soup, EDTA, KAERICON which was developed for decontamination of radionulides on the surface of building structure, and new decontamination agents such as IOCON, TRICON, and CHARCON, which were developed in this study. The absorption of radionuclides through the skin was evaluated by the gamma-tay detection on the surface of sample skin after radionuclides were penetrated into the skin during 16 hour soiling time. The results of this absorption experiment indicated that 11.5% and 3.2% of initial amounts of $^{137}Cs$ and $^{60}Co$, respectively, were panerated into the skin. In the experiment to remove the residual radioactivity fixed on the skin, KAERICON showed the decontamination rates up to 52.1%(decontamination factor of 2.1) and IOCON showed the equivalent decontamination rate (decontamination factor 1.9) for $^{137}Cs$. However, IOCON and CHARCON showed the poor decontamination rates of less than 20%(decontamination factor of 1.2) for $^{60}Co$, and KAERICON showed the poor decontamination rate (decontamination factor 1.1) for $^{60}Co$. For TRICON, the decontamination factors were 1.6 to 1.8 for $^{137}Cs$, and 1.0 to 1.2 for $^{60}Co$, respectively.