• Journal of radiological science and technology
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• v.42 no.1
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• pp.53-59
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• 2019

In the field of nuclear medicine, the various static phantoms of international standards are used to assess the performance of the nuclear medicine equipment. However, we only reproduced a fixed situation in spite of the movement of the cardiac, and the demands for dynamic situations have been continuously raised. More research is necessary to address these challenges. This study used flexible materials to design the dynamic cardiac phantom, taking into account the various clinical situations. It also intended to reproduce the images through dynamic cardiac flow to confirm the usefulness of the proposed technique. The frame of dynamic cardiac phantom was produced based on the international standard phantom. A nuclear medicine dynamic cardiac phantom was produced rubber material and silicone implemented by 3D printing technique to reproduce endocardium and epicardium movement. Therefore we compared and evaluated the image of a cardiac phantom made of rubber material and a cardiac phantom made of silicone material by 3D printing technique. According to the results of this study, the analysis of the Summed Rest Score(SRS) showed abnormalities in the image of a cardiac phantom made of rubber material at 10, 20, and 30 stroke rates, but the image of a cardiac phantom made of silicone material by 3D printing technique showed normal levels. And the analysis of the Total Perfusion Deficit(TPD) showed that TPD in the image of a cardiac phantom made of rubber material was higher than that of the image of a cardiac phantom made of silicone material by 3D printing technique at 10, 20, and 30 stroke rates. The potential for clinical application of the proposed method was confirmed in the dynamic cardiac phantom implemented with 3D printing technique. It is believed that the objective information secures the reliability of inspection equipment and it contributes to improve the diagnostic value of nuclear medicine.

• Journal of radiological science and technology
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• v.45 no.1
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• pp.41-47
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• 2022

The purpose of this study is to apply a deep learning model that can distinguish lung perfusion and lung ventilation images in nuclear medicine, and to evaluate the image classification ability. Image data pre-processing was performed in the following order: image matrix size adjustment, min-max normalization, image center position adjustment, train/validation/test data set classification, and data augmentation. The convolutional neural network(CNN) structures of VGG-16, ResNet-18, Inception-ResNet-v2, and SE-ResNeXt-101 were used. For classification model evaluation, performance evaluation index of classification model, class activation map(CAM), and statistical image evaluation method were applied. As for the performance evaluation index of the classification model, SE-ResNeXt-101 and Inception-ResNet-v2 showed the highest performance with the same results. As a result of CAM, cardiac and right lung regions were highly activated in lung perfusion, and upper lung and neck regions were highly activated in lung ventilation. Statistical image evaluation showed a meaningful difference between SE-ResNeXt-101 and Inception-ResNet-v2. As a result of the study, the applicability of the CNN model for lung scintigraphy classification was confirmed. In the future, it is expected that it will be used as basic data for research on new artificial intelligence models and will help stable image management in clinical practice.

• Korean Journal of Radiology
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• v.22 no.2
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• pp.243-252
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• 2021

Objective: To compare and correlate the findings of intravoxel incoherent motion (IVIM) magnetic resonance (MR) imaging and arterial spin labeling (ASL) imaging in characterizing parotid gland tumors. Materials and Methods: We retrospectively reviewed 56 patients with parotid gland tumors evaluated by MR imaging. The true diffusion coefficient (D), pseudo-diffusion coefficient (D^*), and fraction of perfusion (f) values of IVIM imaging and tumor-to-parotid gland signal intensity ratio (SIR) on ASL imaging were calculated. Spearman rank correlation coefficient, chi-squared, Mann-Whitney U, and Kruskal-Wallis tests with the post-hoc Dunn-Bonferroni method and receiver operating characteristic curve assessments were used for statistical analysis. Results: Malignant parotid gland tumors showed significantly lower D than benign tumors (p = 0.019). Within subgroup analyses, pleomorphic adenomas (PAs) showed significantly higher D than malignant tumors (MTs) and Warthin's tumors (WTs) (p < 0.001). The D^* of WTs was significantly higher than that of PAs (p = 0.031). The f and SIR on ASL imaging of WTs were significantly higher than those of MTs and PAs (p < 0.05). Significantly positive correlation was found between SIR on ASL imaging and f (r = 0.446, p = 0.001). In comparison with f, SIR on ASL imaging showed a higher area under curve (0.853 vs. 0.891) in discriminating MTs from WTs, although the difference was not significant (p = 0.720). Conclusion: IVIM and ASL imaging could help differentiate parotid gland tumors. SIR on ASL imaging showed a significantly positive correlation with f. ASL imaging might hold potential to improve the ability to discriminate MTs from WTs.

• Journal of Radiation Industry
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• v.17 no.4
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• pp.543-549
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• 2023

Thallium-201 (²⁰¹Tl) is a medical radioisotope which emits gamma rays when it decays and used in myocardial perfusion scans in single-photon emission tomography due to its similar properties to potassium. Currently, the Korea Institute of Radiological & Medical Sciences is the only institution producing ²⁰¹Tl in Korea, and optimization of ²⁰¹Tl production research is necessary to meet supply compared to domestic demand. To this end, technical analysis of plating target production and chemical separation methods essential for ²⁰¹Tl production research is conducted. It deals with the process of generating and separating ²⁰¹Tl radioisotope and target production, It can be generated through a nuclear reaction such as ^natHg(p,xn)²⁰¹Tl, ²⁰¹Hg(p,n)²⁰¹Tl, ^natPb(p,xn)²⁰¹Bi → ²⁰¹Pb → ²⁰¹Tl, ²⁰⁵Tl(p,5n)²⁰¹Pb → ²⁰¹Tl, and considering impure nuclide generated simultaneously with the use of proton beam energy of 35 MeV or less, it is intended to be produced using the ²⁰³Tl(p,3n)²⁰¹Pb→²⁰¹Tl nuclear reaction. In particular, the chemical separation of Tl is a very important element, and the chemical separation methods that can separate it is broadly divided into four types, including solid phase extraction, liquid-liquid, electrochemical, and ion exchange membrane separation. Some chemical separations require additional separation steps, such as methods using selective adsorption. Therefore, this technical report describes four chemical separation methods and seeks to separate high-purity ²⁰¹Tl using a method without additional separation steps

• The Korean Journal of Nuclear Medicine Technology
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• v.14 no.2
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• pp.155-158
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• 2010

Purpose: $^{99m}Tc$-macroaggregated albumin (MAA) hepatic arterial perfusion scintigraphy was known for useful method to evaluate patients receiving intraarterial chemotherapy for liver cancer. This study evaluate about usefulness of normal liver on hepatocellular carcinoma (HCC) from HCC patients. This study is to see the usefullness of Hepatic Arterial Perfusion Scintigraphy (HAPS) by measuring mass size, shape, lung shunting and tumor to normal ratio (T/N ratio) in relative blood stream of HCC patients compared with HCC on normal liver. Materials and Methods: From June 2009 to September 2009, HAPS studies were performed on 7 patients (men 6, women 1, mean 64) who were diagnosed HCC. HAPS was performed after proper hepatic artery $^{99m}Tc$-MAA of 5 mCi (185 MBq) injection by catheter. We performed anterior, posterior, both lateral view, SPECT of chest and abdomen. Then we set up ROI and calculated lung shunting, T/N ratio for each count, count/pixel (mean value). Results: Tumor and liver size analyzed by ROI of anterior, posterior view are 2.0-10.8 cm (mean 3.75 cm), 8.8-18.5 cm (mean 14.6 cm). T/N ratio analyzed by total tumor and total normal mean value are 2.41-5.76 (mean 3.8). lung shunting analyzed by total liver count is 3.14-13.92% (mean 6.77%). Conclusion: HAPS with $^{99m}Tc$-MAA can evaluate mass size, location, quantitative analysis through T/N ratio. also HAPS can evaluate detection of arteriovenous shunt through lung uptake before radioisotope therapy. Therefore HAPS with $^{99m}Tc$-MAA can be useful method in aspect of evaluation and treatment of HCC.

• The Korean Journal of Nuclear Medicine Technology
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• v.23 no.1
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• pp.75-79
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• 2019

Purpose Cadmium-zinc-telluride (CZT) camera with semiconductor detector is capable of dynamic myocardial perfusion SPECT for coronary flow reserve (CFR). Image acquisition with the heart positioned within 2 cm in the center of the quality field of view (QFOV) is recommended because the CZT detector based on focused multi-pinhole collimators and is stationary gantry without rotation. The aim of this study was to investigate the optimal method for measuring position of the heart within the center of the QFOV when performing dynamic myocardial perfusion SPECT with the Discovery NM 530c camera. Materials and Methods From June to September 2018, 45 patients were subject to dynamic myocardial perfusion SPECT with D530c. For accurate heart positioning, the patient's heart was scanned with a mobile ultrasound and marked at the top of the probe where the mitral valve (MV) was visible in the parasternal long-axis view (PLAX). And, the marked point on the patient's body matched with the reference point indicated CZT detector in dynamic stress. The heart was positioned to be in the center of the QFOV in rest. The coordinates of dynamic stress and rest were compared statistically. Results The coordinates of the dynamic stress using mobile ultrasound and those taken of the rest were recorded for comparative analysis with regard to the position of the couch and analyzed. There were no statistically significant differences in the coordinates of Table in & out, Table up & down, and Detector in & out (P > 0.05). The difference in distance between the 2 groups was measured at $0.25{\pm}1.00$, $0.24{\pm}0.96$ and $0.25{\pm}0.82cm$ respectively, with no difference greater than 2 cm in all categories. Conclusion The position of the heart taken using mobile ultrasound did not differ significantly from that of the center of the QFOV. Therefore, The use of mobile ultrasound in dynamic stress will help to select the correct position of the heart, which will be effective in clinical diagnosis by minimizing the image quality improvement and the patient's exposure to radiation.

• The Korean Journal of Nuclear Medicine
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• v.21 no.2
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• pp.199-205
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• 1987

The fact there are increase of intrapulmonary arterioveneous shunt amount in the liver cirrhosis patient has been known since 1950. And the method of shunt amount calculation by radionuclide method using $^{99m}Tc-MAA$ was introduced in the middle of 1970. We measured intrapulmonary shunt amount by means of perfusion lung scan using $^{99m}Tc-MAA$ in the various type of liver diseases especially in chronic liver diseases and acute liver disease. The results were as followed. 1) The amount of arteriovenous intrapulmonary shunt in the total case of liver disease was $9.3{\pm}3.9%$, and that of in the control group was $4.6{\pm}2.1%$. 2) The amount of arteriovenous intrapulmonary shunt in the chronic liver disease was $10.8{\pm}4.4%$, and that of in the acute liver disease was $7.2{\pm}2.8%$. We observed significant differences between normal control group and liver disease group, and between chronic liver disease group and acute liver disease group in the amount of shunt by the nucleolide method.

• The Korean Journal of Physiology and Pharmacology
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• v.14 no.2
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• pp.71-75
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• 2010

To investigate the intestinal absorption of a fibrinolytic and proteolytic lumbrokinase extracted from Eisenia andrei, we used rat everted gut sacs and an in situ closed-loop recirculation method. We extracted lumbrokinase from Eisenia andrei, and then raised polyclonal antibody against lumbrokinase. Fibrinolytic activity and proteolytic activity in the serosal side of rat everted gut sacs incubated with lumbrokinase showed dose- and time-dependent patterns. Immunological results obtained by western blotting serosal side solution using rat everted gut sacs method showed that lumbrokinase proteins between 33.6 and 54.7 kDa are absorbed mostly by the intestinal epithelium. Furthermore, MALDI- TOF mass spectrometric analysis of plasma fractions obtained by in situ recirculation method confirmed that lumbrokinase F1 is absorbed into blood. These results support the notion that lumbrokinase can be absorbed from mucosal lumen into blood by oral administration.

• Journal of Chest Surgery
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• v.37 no.11
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• pp.903-910
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• 2004

Background: The total aortic arch replacement is one of the most difficult operations with high mortality rate. But the arch first technique with subclavian arterial perfusion has been reported to be a safe methods for arch replacement. Material and Method: Between Feb 2003 and July 2004, 18 patients, 10 men and 8 women, underwent total aortic arch replacement with arch first technique. Their mean age was $59.3\pm12.9$ years. The patietns received 11 acute aortic dissections, 3 chronic aortic dissectiong aneurysms, and 4 ruptured aortic arch aneurysms. Result The mean admission period was $20.2\pm7.4$ days. There was one early mortality case which died of low cardiac output syndrome and another late mortality case which died of cerebral hemorrhage. The others were discharged without any sequelae and they were followed up for an average period of $180\pm156.3$ days. Conclusion: The total aortic arch replacement with arch first technique and subclavian arterial perfusion is a good method that will reduce the surgical mortality and the possibility of secondary late reoperation from the remnant distal aortic problems.

• The Korean Journal of Nuclear Medicine Technology
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• v.17 no.1
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• pp.18-24
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• 2013

Purpose: Myocardial perfusion SPECT using $^{201}Tl$ is an important method for viability of left ventricle and quantitative evaluation of cardiac function and now various reconstruction methods are used to improve the image quality. But in case of small sized heart, you should always be careful because of the Partial Volume Effect which may cause errors of quantitative indices at the reconstruction step. So, In this study, we compared those quantitative indices of left ventricle according to the reconstruction method of myocardial perfusion SPECT with the Echocardiography and verified the degree of the differences between them. Materials and Methods: Based on ESV 30 mL of Echocardiography, we divided 278 patients (male;98, female;188, Mean age;$65.5{\pm}11.1$) who visited the Asan medical center from February to September, 2012 into two categories; below the criteria to small sized heart, otherwise, normal or large sized heart. Filtered and output each case, we applied the method of FBP and OSEM to each of them, and calculated EDV, ESV and LVEF, and we conducted statistical processing through Repeated Measures ANOVA with indices that measured in Echocardiography. Results: In case of men and women, there were no significant difference in EDV between FBP and OSEM (p=0.053, p=0.098), but in case of Echocardiography, there were meaningful differences (p<0.001). The change of ESV especially women in small sized heard, significant differences has occurred among FBP, OSEM and Echocardiography. Also, in LVEF, there were no difference in men and women who have normal sized heart among FBP, OSEM and Echocardiography (p=0.375, p=0.969), but the women with small sized heart have showed significant differences (p<0.001). Conclusion: The change in quantitative indices of left ventricle between Nuclear cardiology image reconstruction, no difference has occurred in the patients with normal sized heart but based on ESV, under 30 mL of small sized heart, especially in female, there were significant differences in FBP, OSEM and Echocardiography. We found out that overestimated LVEF caused by PVE can be reduced in average by applying OSEM to all kinds of gamma camera, which are used in analyzing the differences.