• Proceedings of the Korean Society of Computer Information Conference
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• 2023.07a
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• pp.179-181
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• 2023

본 논문에서는 GAN 기반의 영상 생성 방법론을 이용해 delayed PET 영상을 생성하는 연구를 수행하였다. PET은 양전자를 방출하는 방사성 동위원소를 표지한 방사성의약품의 체내 분포를 시각화함으로서 암 세포 진단에 이용되는 의료영상 기법이다. 하지만 PET의 스캔 과정에서 방사성의약품이 체내에 분포하는 데에 걸리는 시간이 오래 걸린다는 문제점이 존재한다. 따라서 본 연구에서는 방사성의약품이 충분히 분포되지 않은 상태에서 얻은 PET 영상을 통해 목표로 하는 충분히 시간이 지난 후에 얻은 PET 영상을 생성하는 모델을 GAN (generative adversarial network)에 기반한 image-to-image translation(I2I)를 통해 수행했다. 특히, 생성 전후의 영상 간의 영상 쌍을 고려한 paired I2I인 Pix2pix와 이를 고려하지 않은 unpaired I2I인 CycleGAN 두 가지의 방법론을 비교하였다. 연구 결과, Pix2pix에 기반해 생성한 delayed PET 영상이 CycleGAN을 통해 생성한 영상에 비해 영상 품질이 좋음을 확인했으며, 또한 실제 획득한 ground-truth delayed PET 영상과의 유사도 또한 더 높음을 확인할 수 있었다. 결과적으로, 딥러닝에 기반해 early PET을 통해 delayed PET을 생성할 수 있었으며, paired I2I를 적용할 경우 보다 높은 성능을 기대할 수 있었다. 이를 통해 PET 영상 획득 과정에서 방사성의약품의 체내 분포에 소요되는 시간을 딥러닝 모델을 통해 줄여 PET 이미징 과정의 시간적 비용을 절감하는 데에 크게 기여할 수 있을 것으로 기대된다.

• Korean Journal of Otorhinolaryngology-Head and Neck Surgery
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• v.61 no.12
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• pp.697-701
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• 2018

Background and Objectives The aim of this study was to evaluate surgical completeness in endoscopic total thyroidectomy with central neck dissection via unilateral axillo-breast approach (UABA) compared with bilateral axillo-breast (BABA) and open approach (OA) by means of the radioactive iodine uptake (RAIU) ratio and thyroglobulin (Tg) of remnant thyroid. Subjects and Method From July 2010 to March 2013, 82 patients who had underwent total thyroidectomy with central neck dissection and postoperative radioactive iodine (RAI) ablation for papillary thyroid carcinoma were enrolled. Of these patients, 27 patients underwent UABA, 24 patients BABA, and 31 patients OA. Clinicopathologic data, surgical outcome, stimulated Tg and RAIU ratio on the first postoperative RAI ablation scan were compared among 3 groups. Results Patients in the endoscopic surgery groups (UABA, BABA) were younger than those in the OA groups. Invasiveness such as operation time, postoperative pain, and drain amount in UABA was less than that in BABA and severer than that in OA. Other variables regarding clinicopathologic and surgical data were not significantly different. Stimulated Tg and RAIU ratio did not show significant differences among 3 groups (p=0.659 and p=0.664). Conclusion The completeness of UABA was comparable with that of BABA and OA. The UABA may be a safe option for patients who need endoscopic thyroidectomy for papillary thyroid carcinoma.

• Mycobiology
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• v.45 no.4
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• pp.255-262
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• 2017

A total of 121 species of lichens belonging to the genus Arthothelium have been described to date, most of which have been found in tropical regions. Here, we describe the discovery of a novel Arthothelium species for the first time in South Korea. Until now, Arthothelium ruanum was the only Arthothelium species reported in South Korea. Among the 113 specimens collected in this study, we identified A. ruanum and a putative new species, Arthothelium punctatum (J. S. Park & J.-S. Hur, sp. nov.). The diagnostic characters of A. punctatum are as follows: apothecia punctate, shortly elongate to branched, small, 0.1-0.2 mm wide, hypothecium hyaline to pale brown and obovate to broadly ellipsoid, muriform ascospores, $29.5-44.6{\times}12.2-18.2{\mu}m$. The new species was found in Mt. Seokbyeong at an altitude of 790 m on smooth bark. Upon phylogenic analysis, the putative new species, A. punctatum, was separated from other Arthothelium species although the specimens analyzed were clustered with Arthoniaceae in phylogenetic trees based on both the mitochondrial small subunit (mtSSU) sequence and combined mtSSU and nuclear ribosomal large subunit sequences. Our data clearly indicate that this species is a new species belonging to the family Arthoniaceae. To elucidate the taxonomic characteristics of the new species, we provide morphological descriptions and a distribution map.

• Annals of Hepato-Biliary-Pancreatic Surgery
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• v.28 no.1
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• pp.34-41
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• 2024

Backgrounds/Aims: Liver transplantation (LT) provides a favorable outcome for patients with hepatocellular carcinoma (HCC) and was launched in Vietnam in 2004. In this study, we evaluated the short-term and long-term outcomes of LT and its risk factors. Methods: This retrospective study analyzed HCC patients who underwent LT at Viet Duc University hospital, Vietnam, from 01/2012-03/2022. The following data were gathered: demographics, virus infection, tumor characteristics, alpha-fetoprotein (AFP) level, Child-Pugh and MELD scores, selection criteria, type of LT, complications, 30-day mortality, and disease-free and overall survival (DFS and OS). Results: Fifty four patients were included, the mean age was 55.39 ± 8.46 years. Nearly 90% had hepatitis B virus-related HCC. The median (interquartile range) AFP level was 16.2 (88.7) ng/mL. The average MELD score was 10.57 ± 5.95; the rate of Child-Pugh A and B were 70.4% and 18.5%, respectively. Nearly 40% of the patients were within Milan criteria, brain-dead donor was 83.3%. Hepatic and portal vein thrombosis occurred in 0% and 1.9%, respectively; hepatic artery thrombosis 1.9%, biliary leakage 5.6%, and postoperative hemorrhage 3.7%. Ninety-day mortality was 5.6%. Five-year DFS and OS were 79.3% and 81.4%, respectively. MELD score and ChildPugh score were predictive factors for DFS and OS (p < 0.05). In multivariate analysis, Child-Pugh score was the only significant factor (p < 0.05). Conclusions: In Vietnam, LT is an effective therapy for HCC with an acceptable complication rate, mortality rate, and good survival outcomes, and should be further encouraged.

• Nutrition Research and Practice
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• v.16 no.5
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• pp.549-564
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• 2022

BACKGROUND/OBJECTIVES: Oxidative stress is caused by an imbalance between harmful free radicals and antioxidants. Long-term oxidative stress can lead to an "exhausted" status of antioxidant defense system triggering development of metabolic syndrome and chronic inflammation. Green perilla (Perilla frutescens) is commonly used in Asian cuisines and traditional medicine in southeast Asia. Green perilla possesses numerous beneficial effects including anti-inflammatory and antioxidant functions. To investigate the potentials of green perilla leaf extract (PE) on oxidative stress, we induced oxidative stress by high-fat diet (HFD) in aging mice. MATERIALS/METHODS: C57BL/6J male mice were fed HFD continuously for 53 weeks. Then, mice were divided into three groups for 12 weeks: a normal diet fed reference group (NDcon), high-fat diet fed group (HDcon), and high-fat diet PE treated group (HDPE, 400 mg/kg of body weight). Biochemical analyses of serum and liver tissues were performed to assess metabolic and inflammatory damage and oxidative status. Hepatic gene expression of oxidative stress and inflammation related enzymes were evaluated by quantitative real-time polymerase chain reaction (qRT-PCR). RESULTS: PE improved hepatopathology. PE also improved the lipid profiles and antioxidant enzymes, including hepatic glutathione peroxidase (GPx) and superoxide dismutase (SOD) and catalase (CAT) in serum and liver. Hepatic gene expressions of antioxidant and anti-inflammatory related enzymes, such as SOD-1, CAT, interleukin 4 (IL-4) and nuclear factor erythroid 2-related factor (Nrf2) were significantly enhanced by PE. PE also reduced the levels of hydrogen peroxide (H₂O₂) and malondialdehyde (MDA) in the serum and liver; moreover, PE suppressed hepatic gene expression involved in pro-inflammatory response; Cyclooxygenase-2 (COX-2), nitric oxide synthase (NOS), interleukin 1 beta (IL-1β), and interleukin 6 (IL-6). CONCLUSIONS: This research opens opportunities for further investigations of PE as a functional food and possible anti-aging agent due to its attenuative effects against oxidative stress, resulting from HFD and aging in the future.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.6
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• pp.3919-3925
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• 2015

When a patient with thyroid cancer is released from isolation after I-131 treatment and return to home using a vehicle, travel time should be controlled to reduce the amount of radiation to accompanying person. As the calculation of appropriate travel time is difficult, there is no patient-specific guideline until now. If we assume that there is no excretion and no physical decay during the relatively short travel time, calculation become quite simple; total radiation dose = dose rate ${\times}$ travel time. Results of this simple calculation and conventional calculation were compared using datum from 120 patients. Travel time calculated by simple method was 56% of conventional method in 0.3 m, 91% in 0.5 m and 96% in 1 m. Simple method was safe. It can be applied easily and also can be applied to the patients with hyperthyroidism treated by I-131.

• Journal of Digital Convergence
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• v.12 no.10
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• pp.385-390
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• 2014

This research is conducted to identify whether an m-DIXON technique which is useful for an abdomen MRI examination compared with an existing e-THRIVE technique is a clinically useful or not. There was evaluated quantitative and qualitative to 84 subjects who had abdomen MRI exam due to their liver disease were conducted during a period from September in 2013 to February in 2014. First of all the quantitative evaluation, the m-DIXON technique's SNR was $90.42{\pm}16.90$ and the e-THRIVE technique was $60.42{\pm}11.54$ and the m-DIXON technique's CNR was $52.38{\pm}22.58$ and the e-THRIVE technique was $46.31{\pm}20.25$. Secondly in the qualitative evaluation, the m-DIXON technique's image quality was $4.06{\pm}0.34$, a artifact was $3.64{\pm}0.22$, and fat suppression was $4.16{\pm}0.15$, the e-THRIVE technique's image quality was $3.14{\pm}0.35$, a artifact was $3.06{\pm}0.38$, fat suppression was $3.14{\pm}0.30$. In conclusion, m-DIXON technique for abdomen MRI examination showed superiority over both SNR as a quantitative anaylsis, CNR and a qualitative analysis.

• Journal of Radiation Industry
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• v.9 no.2
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• pp.85-90
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• 2015

Purpose: Time of operation has been reduced and accuracy of operation has been improved since C-arm, which offer real-time image of patient, was introduced in operation room. However, because of the contamination of patient, C-arm could not be used more appropriately. Therefore, this study is to know factors of controlling exposure dose, image quality and the exposed dose of health professional in operation room. Materials and methods: Height of Wilson frame (bed for operation) was fixed at 130 cm. Then, Model 76-2 Phantom, which was set by assembling manual of Fluke Company, was set on the bed. Head/Spine Fluoroscopy AEC mode was set for exposure condition. According to detector size of C-arm, the absorbed dose per min was measured in the 7 steps OFD (cm) from 10 cm to 40 cm (10, 15, 20, 25, 30, 35, 40 cm). In each step of OFD, the absorbed dose per min of same diameter of collimation was measured. Moreover, using Nero MAX Model 8000, exposure dose per min was measured according to 3 step of distance from detector (20 cm, 60 cm, 100 cm). Finally, resolution was measured by CDRH Disc Phantom and magnification of each OFD was measured by aluminum stick bar. Result: According to detector size of C-arm, difference of absorbed dose shows that the dose of 20 cm OFD is 1.750 times higher than the dose of 40 cm OFD. It means that the C-arm, which has smaller size of detector, shows the bigger difference of absorbed dose per min (p<0.05). In the difference of absorbed dose in the same step of OFD (from 20 cm to 40 cm), the absorbed dose of 9 inch detect or C-arm was 1.370 times higher than 12 inch' s (p<0.05). When OFD was set to 20 cm OFD, the absorbed dose of non-collimation case was approximately 0.816 times lower than the absorbed dose of collimation cases (p<0.05). When the distance was 20 cm from detector, exposed does includes first-ray and scatter-ray. When the distance was 60 cm and 100 cm from detector, exposed does includes just scatter-ray. So, there was the 2.200 times difference of absorbed does. Finally, when OFD was increased, spatial resolution was 4 to 5 step was increased. However, low contrast resolution was not relative. Moreover, there was 1.363 times difference of magnification (p<0.05). Conclusion: When C-Arm is used, avoiding contamination of patient is more important factor than reducing exposed dose of health professional in operation room. Just controlling exposure time is just way to reduce the exposed does of workers. However, in the case, non-probability influence could be occurred. Therefore, this study proved that the exposed dose will be reduced if the factors such as using small detector size of C-arm, setting OFD from 20 cm to 25 cm and non-collimating. Moreover, dose management of C-arm in the non-interesting area will be considered additionally.

• Korean Journal of Veterinary Research
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• v.27 no.2
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• pp.277-290
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• 1987

This paper dealt with etiological studies on the acute fatal disease of Angora rabbits occurring as a group in Korea. The disease was confirmed as an acute infectious disease caused by virus. The results obtained were summarized as follows: The disease produced a high morbidity in the rearing Angora rabbits and a high mortality in the infected rabbits, and was acute. The infected rabbits died soon without premonitory signs after inappetence. The body temperature of the affected rabbits rose to $40^{\circ}C$ and nearly all deaths occurred within 48 hours after inoculation. In many cases a bloody foam was visible from the nostrils after death. According to the progress of the disease the nervous signs, such as ataxia, paralysis of the legs, and torticollis could be recognized in the some cases. Rabbits that had recovered from the disease were severe emaciation, and bristly and sparse hairs. In macroscopical findings, there were hemorrhage and edema of the lung, hemorrhage or hyperemia of the tracheal and broncheal mucosae, appearance of blood-tinged effusion in the respiratory tract. The principal lesions were found in the liver. Usually the lobular necrosis of the liver cells was progressed, and focal necrosis and hemorrhagic spots of various sizes were often observed in the liver. Liver was as a whole pale. In chronic cases, however, there was a slight liver cirrhosis with the atrophy of the parenchymal cells. The other lesions encountered grossly consisted of swelling and petechiae of the kidney, hyperemia and hemorrhage of the spleen, catarrh of the small intestine, and hyperemia of the brain. The urinary bladder contained a lot of turbid urine or bloody urine and urinary cast, and was distended with the urine. In microscopical findings, the most striking lesions occurred in the liver and may be classified as viral hepatitis. The hepatic lesions were initially characterized by progression from periportal to peripheral necrosis of the lobules with the infiltration of mononuclear cells. Focal necrosis of various sizes, hemorrhage and hyperemia were often observed in the hepatic lobules. In chronic cases, there were intensive infiltration of lymphocytes, proliferation of fibroblasts, appearance of plasmal cells, and atrophy of parenchymal cells in the hepatic tissue. Perivascular lymphocytic infiltration and meningitis were seen in the brain and spinal cord. In the kidney, there were acute glomerulonephritis, hemorrhage, necrosis of the uriniferous tubules, and retention of eosinophilic substance within the renal tubules. Proliferation of fibroblasts and infiltration of mono-nuclear cells were found in the interstitial stroma of the kidney in chronic case. There were also hemorrhage and edema in the lung, hyperemia and hemorrhage in the trachea and bronchus, perivascular lymphocytic infiltration and focal myocardial necrosis in the heart, hyperemia and hemorrhage in the spleen, vacuolization and desquamation of mucous epithelia in the urinary bladder, catarrhal inflammation of the small intestine, hemorrhage in the adrenal cortex and hyperemia in the other organs. In the electron microscopical findings of the hepatic tissue, crystals of viral particles appeared in the cytoplasm of the hepatocytes and the sinusoidal endothelial cells, and the viral particles, were small in size and polygonal. The authors suppose the virus may belong to picornaviridae family of RNA viruses. Also immature virus-like particles, dilated rough endoplasmic reticulum and destruction of nuclear membrane were seen in the hepatocytes. From these results, it is concluded that the sudden death is an acute viral disease characterized by hepatitis and the affected rabbits may be died of viremia.

• The Korean Journal of Nuclear Medicine
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• v.34 no.5
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• pp.403-409
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• 2000

Objectives: Due to the heterogeneous receptor distribution and changes of receptor status over time, the biochemical measurement of estrogen receptor status of biopsy specimens is not sufficient to diagnose breast cancer. As a result, I-123 labeled estradiols have been applied for the diagnosis. The purpose of this study was to develop a suitable radioligand for imaging estrogen receptor-positive human breast tumors. Methods: Among the various estradiol derivatives, $17{\alpha}-[^{123}I]$iodovinyl estradiol ($[^{123}I]$IVE) has been prepared from $17{\alpha}$-ethynyl estradiol. Labeling of $E-17{\alpha}-[^{123}I]$iodovinyl estradiol (E-$[^{123}I]$IVE) was carried out using peracetic acid with $[^{123}I]NaI\;and\;Z-[^{123}I]IVE$ labelling was archived using chloamine-T/HCl solution with $[^{123}I]$NaI. Labeling yield was determined by silica thin-layer chromatography (TLC) and radiochemical purity was measured by high performance liquid chromatography (HPLC). The biodistribution of E-$[^{123}I]$IVE was measured in immature female rats at 60 min, 120 min and 300 min after injection. Results: The labeling yield of two isomers was 92% and 94% ($E-[^{123}I]IVE\;and\;Z-[^{123}I]IVE$, respectively). The radiochemical purity was more than 98% after purification. The highest uptake was observed at 120 min in uterus (3.11% ID/g for E-$[^{123}I]$IVE). Conclusion: These results suggest the possibility of using E-$[^{123}I]$IVE as an imaging agent for the evaluation of the evaluation of the presence of estrogen receptor in patients with breast cancer.