• The Korean Journal of Nuclear Medicine Technology
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• v.24 no.1
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• pp.15-19
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• 2020

Purpose Generative Adversarial Network(GAN) is one of deep learning technologies. This is a way to create a real fake image after learning the real image. In this study, after acquiring artificial intelligence images through GAN, We were compared and evaluated with real scan time images. We want to see if these technologies are potentially useful. Materials and Methods 30 patients who underwent ¹⁸F-FDG Brain PET/CT scanning at Severance Hospital, were acquired in 15-minute List mode and reconstructed into 1,2,3,4,5 and 15minute images, respectively. 25 out of 30 patients were used as learning images for learning of GAN and 5 patients used as verification images for confirming the learning model. The program was implemented using the Python and Tensorflow frameworks. After learning using the Pix2Pix model of GAN technology, this learning model generated artificial intelligence images. The artificial intelligence image generated in this way were evaluated as Mean Square Error(MSE), Peak Signal to Noise Ratio(PSNR), and Structural Similarity Index(SSIM) with real scan time image. Results The trained model was evaluated with the verification image. As a result, The 15-minute image created by the 5-minute image rather than 1-minute after the start of the scan showed a smaller MSE, and the PSNR and SSIM increased. Conclusion Through this study, it was confirmed that AI imaging technology is applicable. In the future, if these artificial intelligence imaging technologies are applied to nuclear medicine imaging, it will be possible to acquire images even with a short scan time, which can be expected to reduce artifacts caused by patient movement and increase the efficiency of the scanning room.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.30 no.6
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• pp.572-576
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• 2008

Gorham-Stout disease is a rare skeletal disease which is progressive and spontaneous and idiopathic resorption of whole body bone. In the initial stage, the osteolytic site is replaced by histologically benign vascular proliferation without new bone formation and finally by dense fibrous tissues. We encountered with a patient involving the mandible with attention by the clinical, radiographic, scintigraphic, angiographic, and computed tomography. We resected the mandibular lesion which was reconstructed with a fibular free flap. We report literature review with a mandibular lesion involved with Gorham-Stout disease.

• Journal of the Korean Society of Radiology
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• v.83 no.5
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• pp.991-1002
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• 2022

Biliary atresia is a rare but significant cause of neonatal cholestasis. An early and accurate diagnosis is important for proper management and prognosis. To diagnose biliary atresia, various imaging studies using ultrasonography, MRI, hepatobiliary scans, and cholangiography can be performed, although ultrasonography is more important for initial imaging studies. In this article, we review the findings of biliary atresia from various imaging modalities, including ultrasonography, MRI, hepatobiliary scans, and cholangiography. The known key imaging features include abnormal gallbladder size and shape, periportal thickening visible as a 'triangular cord' sign, invisible common bile duct, increased hepatic arterial flow, and combined anomalies. Aside from the imaging findings of biliary atresia, we also reviewed the diagnostic difficulty in the early neonatal period and the role of imaging in predicting hepatic fibrosis. We hope that this review will aid in the diagnosis of biliary atresia.

• The Korean Journal of Nuclear Medicine
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• v.19 no.2
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• pp.101-103
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• 1985

Azygos system, one of the main collateral vessels which communicates superior vena cava with inferior vena cava, is well visualized by Xray angiography. This system is rarely demonstrated by radioisotope study. We report a case whose azygos system was shown during $^{99m}Tc-DTPA$ renal scanning.

• The Korean Journal of Nuclear Medicine Technology
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• v.22 no.1
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• pp.23-27
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• 2018

Purpose The introduction of bone scan has been reported as a useful tool in the diagnosis, treatment, and treatment response of skeletal disease. The purpose of this study is to improve the anatomical information and tolerance of the bone by combining bone scan and pelvic X-ray without additional radiation exposure. Materials and Methods From November 2015 to August 2016, 236 patients(64 men and 172 women, average age $50.96{\pm}15.39years$) take Bone scan and Pelvis AP(Anteroposterior) X-ray scan at the National Cancer Center. The scan equipment was a gamma camera, Symbia Ecam (SIEMENS, Germany), and a digital x-ray, DRS-800 (Listem, Korea). Osirix version 3.8.1 (Osirix, USA) and Stata/SE version 14.0 (StataCorp, USA) were used for image combination and analysis. The patient was intravenously injected with $^{99m}Tc-DPD$ (740 MBq), and the scan was performed 2 to 4 hours later. Gamma camera image acquisition were Matrix size $256{\times}1024$, Zoom 1.00, and scan speed 17 cm/min. The digital X-ray was made with a collimator size of $14^{{\prime}{\prime}}{\times}17^{{\prime}{\prime}}$, 77 kVp (60 to 97 kVp) and an average of 30 mAs (20 to 48). ASIS and pubic symphysis Select virtual points then Combine three virtual points and pelvic contour lines. The acquired images were evaluated by three radiologists who worked for more than 5 years in the nuclear medicine department. Results Of the total 236 patients, 216 (91.53%) were matched. The median and range (min~max) of the age were 67 (46~81) years old in the unmatched group and 52 (22~87) years old in the matched group, The Wilcoxon rank-sum test was performed to determine whether age was different between the two groups. As a result, the age difference between the two groups was statistically significant at p < 0.0001. Of the 64 men, 60 (93.75%) were match and of the 172 women, 156 (93.75%) were match. There was no statistically significant difference according to gender(p = 0.4542). Of the 54 patients without pelvic lesions, 54 (100.00%) were match, and 162 (89.01%) of 182 patients with pelvic lesions were match. There was a statistically significant difference according to the presence of pelvic lesions. Conclusion There are many variables in the combination of bone scan and pelvic X-ray imaging, and the patient's age and pelvic lesion may have some effect on the image combination. This study is expected to be useful for the diagnosis of pelvic osteosarcoma of children without radiation exposure. It is expected that this combination of images will help to develop the nuclear medicine image.

• The Korean Journal of Nuclear Medicine Technology
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• v.18 no.1
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• pp.158-162
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• 2014

Purpose: Reference material (RM) is defined as material that is safe and homogeneous enough about specified characteristic that is made with a purpose of using test of measurement or nominal characteristic. Certified reference material (CRM), which is issued by authorized organization, is defined as reference material that provides characteristic value, link uncertainty and retroactivity. The purpose of this paper was to evaluate recovery of radioimmunoassay by Certified Reference Material enclosed with a certificate and therefore to enhance reliability of test. Materials and Methods: WHO certified reference material is purchased from NIBSC (National Institute for Biological Standard and Control, United Kingdom) and made of 3 levels that are C-1 (low concentration), C-2 (medium concentration) and C-3 (high concentration) and measured for kit at the Seoul National University Hospital. Recovery rate is evaluated after measurement at four different days. Results: Recovery rate results using WHO certified reference material are T4 90%, Ferritin 88%, PSA 94%, Prolactin 99%, AFP 94% and TSH 93%. Conclusion: A procedure that appropriate accuracy, precision, specificity, sensitivity, reproducibility, and validate on the subject of kit for radioimmunoassay is essential. Recovery rate assay as extraction efficiency of analysis process is percent about already measuring results of analysis result after all measuring process. This is very important assessment standards of performance evaluation of immunoassay kit. Recovery rate results of 6 type used WHO CRM are satisfactory to 88~99%. This demonstrates that the radioimmunoassay is a very accurate measurement, which is very effectively utilized in clinical practice.

• The Korean Journal of Nuclear Medicine Technology
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• v.20 no.2
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• pp.36-41
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• 2016

Purpose Sentinel lymphoscintigraphy (SLS) was using only $^{99m}Tc-phytate$. If the supply is interrupted temporarily, there is no alternative radiopharmaceuticals. The aim of this study measure the particle size of radiopharmaceuticals and look for radiopharmaceuticals which can be substituted for $^{99m}Tc-phytate$. Materials and Methods The particle size of radiopharmaceuticals were analyzed by a nano-particle analyzer. This study were selected known radiopharmaceuticals to be useful particle size for SLS. We were divided into control and experimental groups using $^{99m}Tc-DPD$, $^{99m}Tc-MAG3$, $^{99m}Tc-DMSA$ with $^{99m}Tc-phytate$. For in-vivo experiment, radiopharmaceuticals were injected intradermally at both foot to perform lymphoscintigraphy. Imaging was acquired to dynamic and delayed static image and observe the inguinal lymph nodes with the naked eye. Results Particle size was measured respectively Phytate 105~255 nm (81.9%), MAG3 91~255 nm (98.7%), DPD 105~342 nm (77.3%), DMSA 164~ 342 nm (99.2%), MAA 1281~2305 nm (90.6%), DTPA 342~1106 nm (79.4%), and HDP 295~955 nm (94%). In-vivo delayed static image, inguinal lymph nodes of all experiment groups and two control groups are visible to naked eye. however, $^{99m}Tc-MAG3$ of control groups is not visible to naked eye. Conclusion We were analyzed to the particle size of the radiopharmaceuticals that are used in in-vivo. Consequently, $^{99m}Tc-DPD$, $^{99m}Tc-DMSA $are possible in an alternative radiopharmaceuticals of emergency.

• The Korean Journal of Nuclear Medicine Technology
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• v.14 no.1
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• pp.78-82
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• 2010

Purpose: Recently, South Korea has seen a rapidly increased incidence of both breast and thyroid cancers. As a result, the I-131 scan and lymphoscintigraphy have been performed more frequently. Although this type of diagnostic imaging is prominent in that visualizes pathological conditions, which is similar to previous nuclear diagnostic imaging techniques, there is not much anatomical information obtained. Accordingly, it has been used in different ways to help find anatomical locations by transmission scan, however the results were unsatisfactory. Therefore, this study aims to realize an imaging technique which shows more anatomical information through the fusion of gamma and realistic imaging. Materials and Methods: We analyzed the data from patients who were examined by the lymphoscintigraphy and I-131 additional scan by Symbia Gamma camera (SIEMENS) in the nuclear medicine department of the National Cancer Center from April to July of 2009. First, we scanned the same location in patients by using a miniature camera (R-2000) in hyVISION. Afterwards, we scanned by gamma camera. The data we obtained was evaluated based on the scanning that measures an agreement of gamma and realistic imaging by the Gamma Ray Tool fusion program. Results: The amount of radiation technicians and patients were exposed was generated during the production process of flood source and applied transmission scan. During this time, the radiation exposure dose of technicians was an average of 14.1743 ${\mu}Sv$, while the radiation exposure dose of patients averaged 0.9037 ${\mu}Sv$. We also confirmed this to matching gamma and realistic markers in fusion imaging. Conclusion: Therefore, we found that we could provide imaging with more anatomical information to clinical doctors by fusion of system of gamma and realistic imaging. This has allowed us to perform an easier method in which to reduce the work process. In addition, we found that the radiation exposure can be reduced from the flood source. Eventually, we hope that this will be applicable in other nuclear medicine studies. Therefore, in order to respect the privacy of patients, this procedure will be performed only after the patient has agreed to the procedure after being given a detailed explanation about the process itself and its advantages.

• The Korean Journal of Nuclear Medicine Technology
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• v.15 no.1
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• pp.90-93
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• 2011

Purpose: A Pixelated BSGI gamma camera has features to enhance resolution and sensitivity and minimize the distance between detector and organs by narrow FOV. Therefore, it is known as useful device to examine small organs such as thyroid, parathyroid and gall bladder. In general, when we would like to enlarge the size of images and obtain high resolution images by gamma camera in nuclear medicine study, we use pinhole collimator. The purpose of this study is to evaluate the usefulness of Pixelated BSGI gamma camera and to compare to it using pinhole collimator in thyroid scan which is a study of typical small organs. Materials and methods: (1) The evaluation of sensitivity and spatial resolution: We measured sensitivity and spatial resolution of Pixelated BSGI with LEHR collimator and Infinia gamma camera with pinhole collimator. The sensitivity was measured by point source sensitivity test recommended by IAEA. We acquired images considering dead time in BSGI gamma camera for 100 seconds and used $^{99m}TcO4-\;400{\mu}Ci$ line source. (2) The evaluation of thyroid phantom: The thyroid phantom was filled with $^{99m}TcO4-$. After set 300 sec or 100 kcts stop conditions, we acquired images from both pixelated BSGI gamma camera and Infinia gamma camera with LEHR collimator. And we performed all thyroid studies in the same way as current AMC's procedure. Results: (1) the result of sensitivity: As a result, the sensitivity and spatial resolution of pixelated BSGI gamma camera were better than Infinia's. The sensitivities of pixelated BSGI and Infinia gamma camera were $290cps/{\mu}Ci$ and $350cps/{\mu}Ci$ respectively. So, the sensitivity of pixelated BSGI was 1.2 times higher than Infinia's (2) the result of thyroid phantom: Consequently, we confirmed that images of Pixelated BSGI gamma camera were more distinguishable between hot and cold spot compared with Infinia gamma camera. Conclusion: A pixelated BSGI gamma camera is able to shorten the acquisition time. Furthermore, the patients are exposed to radiation less than before by reducing amount of radiopharmaceutical doses. Shortening scan time makes images better by minimizing patient's breath and motion. And also, the distance between organ and detector is minimized because detector of pixelated BSGI gamma camera is small and possible to rotate. When patient cannot move at all, it is useful since device is feasible to move itself. However, although a pixelated BSGI gamma camera has these advantages, the effect of dead time occurs over 2000 cts/s since it was produced only for breast scan. So, there were low concentrations in organ. Therefore, we should consider that it needs to take tests to adjust acquisition time and amount of radiopharmaceutical doses in thyroid scan case with a pixelated BSGI gamma camera.

• Journal of radiological science and technology
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• v.47 no.3
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• pp.213-218
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• 2024

The myocardial nuclear medicine examination is widely performed to diagnose myocardium disease using various radionuclides. Although image quality according to radionuclides has improved, the radiation exposure for target organ as well as peripheral organs should be considered. Here, the aim of this study was to evaluate absorbed dose (Gy) for peripheral organs in myocardial nuclear medicine scan from myocardium according to various scan environments based on Monte Carlo simulation. The simulation environment was modeled 5 cases, which were considered by radionuclides, number of injections, and radiodosage. In addition, the each radionuclide simulation such as distribution fraction was considered by recommended standard protocol, and the mesh computational female phantom, which is provided by International Commission on Radiological Protection (ICRP) 145, was used using the particle and heavy ion transport code system (PHITS) version 3.33. Based on the results, the closer to the myocardium, the higher the absorbed dose values. In addition, application for dual injection for radionuclides leaded to high absorbed dose compared with single injection for radionuclide. Consequently, there is difference for absorbed dose according to radionuclides, number of injections, and radiodosage. To detect the accurate diseased area, acquisition for improved image quality is crucial process by injecting radionuclides, however, we need to consider absorbed dose both target and peripheral inner organs from radionuclides in terms radiation protection for patient.