• Nuclear Engineering and Technology
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• 제52권11호
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• pp.2594-2600
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• 2020

A gamma camera system using radionuclide has a functional imaging technique and is frequently used in the field of nuclear medicine. In the gamma camera, it is extremely important to improve the image quality to ensure accurate detection of diseases. In this study, we designed a blind-deconvolution framework after a noise-reduction algorithm based on a non-local mean, which has been shown to outperform conventional methodologies with regard to the gamma camera system. For this purpose, we performed a simulation using the Monte Carlo method and conducted an experiment. The image performance was evaluated by visual assessment and according to the intensity profile, and a quantitative evaluation using a normalized noise-power spectrum was performed on the acquired image and the blind-deconvolution image after noise reduction. The result indicates an improvement in image performance for gamma camera images when our proposed algorithm is used.

• Communications for Statistical Applications and Methods
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• 제27권2호
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• pp.201-210
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• 2020

Baseline-category logit random effects models have been used to analyze longitudinal nominal data. The models account for subject-specific variations using random effects. However, the random effects covariance matrix in the models needs to explain subject-specific variations as well as serial correlations for nominal outcomes. In order to satisfy them, the covariance matrix must be heterogeneous and high-dimensional. However, it is difficult to estimate the random effects covariance matrix due to its high dimensionality and positive-definiteness. In this paper, we exploit the modified Cholesky decomposition to estimate the high-dimensional heterogeneous random effects covariance matrix. Bayesian methodology is proposed to estimate parameters of interest. The proposed methods are illustrated with real data from the McKinney Homeless Research Project.

• Nuclear Engineering and Technology
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• 제40권4호
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• pp.277-284
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• 2008

Recently, the long-term operation of a nuclear power plant beyond its licensed term has become a worldwide trend as long as the safety of the plant is maintained in the extended period. Kori Unit 1, the oldest PWR in Korea, is the foremost example of this type of long-term operation in Korea. Comprehensive technical evaluation of the long-term operation of this plant was completed to confirm the overall safety of the plant. The technical evaluation included a review of PSR results, an assessment on aging management programs and time limited aging analyses, and a statement of radiological impact on the environment. Based on all of the results of the technical evaluation activities, Kori Unit 1 was approved to operate for an additional 10 years beyond its original design life of 30 years.

• 한국임상수의학회지
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• 제38권1호
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• pp.16-20
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• 2021

Recently, a new method of evaluating left atrial size called vertebral left atrial size (VLAS) was introduced in dogs. Total 155 dogs were examined at the Veterinary Medical Teaching Hospital of Chungnam National University. In this study, myxomatous mitral valve disease (MMVD) stage and VLAS showed a significant correlation in those dogs. Also, the relationship between C-reactive protein (CRP) and VLAS has yet to be examined. We found a strong positive correlation between VLAS and CRP-a significant increase in CRP was observed with increasing VLAS values. Thus, it would be beneficial to measure VLAS besides employing the current radiological and echocardiographic methods when evaluating heart size. Measuring VLAS could be an additional diagnostic tool for diagnosing MMVD in dogs.

• Journal of Trauma and Injury
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• 제36권4호
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• pp.411-415
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• 2023

An odontoid process fracture is a serious type of cervical spine injury. This injury is categorized into three types based on the location of the fracture. Severe or even fatal neurological deficits can occur due to associated cord injury, which can result in complete quadriplegia. Computed tomography is the primary diagnostic tool, while magnetic resonance imaging is used to evaluate any associated cord injuries. These injuries can occur either directly from the injury or during transportation to the hospital if mishandled. There are two main treatment approaches: surgical fixation or external nonsurgical fixation, with various types and models of fixation devices available. In this case study, computed tomography follow-up confirmed that external fixation can yield successful results in terms of complete healing, even in cases complicated by other factors that may impede healing, such as pregnancy.

• Korean Journal of Radiology
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• 제22권8호
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• pp.1225-1239
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• 2021

During the past decade, researchers have investigated the use of computer-aided mammography interpretation. With the application of deep learning technology, artificial intelligence (AI)-based algorithms for mammography have shown promising results in the quantitative assessment of parenchymal density, detection and diagnosis of breast cancer, and prediction of breast cancer risk, enabling more precise patient management. AI-based algorithms may also enhance the efficiency of the interpretation workflow by reducing both the workload and interpretation time. However, more in-depth investigation is required to conclusively prove the effectiveness of AI-based algorithms. This review article discusses how AI algorithms can be applied to mammography interpretation as well as the current challenges in its implementation in real-world practice.

• Korean Journal of Radiology
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• 제21권10호
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• pp.1126-1137
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• 2020

Imaging plays a key role in the management of brain tumors, including the diagnosis, prognosis, and treatment response assessment. Radiomics and deep learning approaches, along with various advanced physiologic imaging parameters, hold great potential for aiding radiological assessments in neuro-oncology. The ongoing development of new technology needs to be validated in clinical trials and incorporated into the clinical workflow. However, none of the potential neuro-oncological applications for radiomics and deep learning has yet been realized in clinical practice. In this review, we summarize the current applications of radiomics and deep learning in neuro-oncology and discuss challenges in relation to evidence-based medicine and reporting guidelines, as well as potential applications in clinical workflows and routine clinical practice.

• 방사선산업학회지
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• 제18권2호
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• pp.141-145
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• 2024

In Publication No. 66 of the International Commission on Radiological Protection, an activity median aerodynamic diameter (AMAD) of 5 ㎛ is considered in internal exposure dose assessment owing to inhalation of radionuclides in a workplace. However, analysis of aerosols generated during dismantling experiments, such as in the oxy-cutting of a reactor vessel conducted in Korea, revealed that the radioactive aerosols have AMAD ranging from 0.024 to 0.064 ㎛. Such extremely fine aerosols can induce internal exposure if inhaled. In particular, alpha radionuclides in aerosols can lead to significantly higher levels of radiation exposure than beta and gamma radionuclides, thus highlighting the need to establish appropriate internal exposure radiation protection programs and monitoring systems that specifically address alpha radionuclides when decommissioning nuclear power plants in Korea.

• Hip & pelvis
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• 제34권1호
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• pp.62-67
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• 2022

Posterior wall fractures are the most common type of acetabular fractures. Treatment can be conservative or surgical. Operative treatment is indicated for acetabular fractures that result in hip joint instability and/or incongruity, as well injuries with incarceration of fragments of bone or soft tissue within the hip joint. Surgical treatment can range from open reduction and osteosynthesis to hip arthroplasty. Arthroscopy has recently been used as the main surgical technique or as a reduction aid. In this case a 26-year-old male with a fracture of the posterior wall who underwent a posterior miniinvasive approach, followed by hip arthroscopy. This allowed joint wash, removal of the loose body, confirmation of reduction and absence of intra-articular hardware. Excellent clinical and radiological results were obtained. This case demonstrates the advantage of using hip arthroscopy in assessment of fracture reduction, the absence of intra-articular hardware or fragments, as well as a less invasive approach.

• Journal of Radiation Protection and Research
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• 제45권3호
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• pp.101-107
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• 2020

Background: An important lesson learned from the Fukushima accident is that the transition to the mid- and long-term phases from the emergency-response phase requires less than a year, which is not very long. It is necessary to know how much radioactive material has been deposited in an urban area to establish mid- and long-term countermeasures after a radioactive accident. Therefore, an urban deposition model that can indicate the site-specific characteristics must be developed. Materials and Methods: In this study, the generalized urban deposition velocity and the subsequent variation in radionuclide contamination were estimated based on the characteristics of the Korean urban environment. Furthermore, the application of the obtained generalized deposition velocity in a hypothetical scenario was investigated. Results and Discussion: The generalized deposition velocities of ¹³⁷Cs, ¹⁰⁶Ru, and ¹³¹I for each residence type were obtained using three-dimensional (3D) modeling. For all residence types, the deposition velocities of ¹³¹I are greater than those of ¹⁰⁶Ru and ¹³⁷Cs. In addition, we calculated the generalized deposition velocities for each residential types. Iodine was the most deposited nuclide during initial deposition. However, the concentration of iodine in urban environment drastically decreases owing to its relatively shorter half-life than ¹⁰⁶Ru and ¹³⁷Cs. Furthermore, the amount of radioactive material deposited in nonresidential areas, especially in parks and schools, is more than that deposited in residential areas. Conclusion: In this study, the generalized urban deposition velocities and the subsequent deposition changes were estimated for the Korean urban environment. The 3D modeling was performed for each type of urban residential area, and the average deposition velocity was obtained and applied to a hypothetical accident. Based on the estimated deposition velocities, the decision-making systems can be improved for responding to radioactive contamination in urban areas. Furthermore, this study can be useful to predict the radiological dose in case of large-scale urban contamination and can support decision-making for long-term measurement after nuclear accident.