• Title/Summary/Keyword: Nuclear technique

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Application of sigmoidal optimization to reconstruct nuclear medicine image: Comparison with filtered back projection and iterative reconstruction method

  • Shin, Han-Back;Kim, Moo-Sub;Law, Martin;Djeng, Shih-Kien;Choi, Min-Geon;Choi, Byung Wook;Kang, Sungmin;Kim, Dong-Wook;Suh, Tae Suk;Yoon, Do-Kun
    • Nuclear Engineering and Technology
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    • v.53 no.1
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    • pp.258-265
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    • 2021

  • High levels for noise and a loss of true signal make the quantitative interpretation of nuclear medicine (NM) images difficult. An application of profile optimization using a sigmoidal function in this study was used to acquire the NM images with high quality. And the images were acquired by using three kinds of reconstruction method using each same sinogram: a standard filtered back-projection (FBP), an iterative reconstruction (IR) technique, and the sigmoidal function profile optimization (SFPO). Comparison of image according to reconstruction method was performed to show a superiority of the SFPO for imaging. The images reconstructed by using the SFPO showed an average of 1.49 times and of 1.17 times better in contrast than the results obtained using the standard FBP and the IR technique, respectively. Higher signal to noise ratios were obtained as an average of 12.30 times and of 3.77 times than results obtained using the standard FBP and the IR technique, respectively. This study confirms that reconstruction with SFPO (vs FBP and vs IR) can lead to better lesion detectability and characterization with noise reduction. It can be developed for future reconstruction technique for the NM imaging.

  • https://doi.org/10.1016/j.net.2020.06.029 인용 PDF KSCI

Application of Nuclear Transplantation to Production of Cloned Animals (복제동물 생산을 위한 핵이식기법의 응용)

  • 이효충
    • Journal of Embryo Transfer
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    • v.6 no.2
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    • pp.18-29
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    • 1991

  • Nuclear transplantation technique is known as the most potential and efficient method for producing a large number of genetically identical animals from a single embryo. The technical development of nuclear transplantation in mammals and its application to the production of cloned animals are described. For the efficient and successful production of cloned embryos by nuclear transplantation, the right selection and micromanipulation of recipient eggs or embryos as capacious recipient cytoplasm, the adequate and benefitlal preparation of multiple totipotent embryonic cells as donor nuclei, and also the fusion technique are very critical. Recent studies approaching to these critical points are introduced and discussed. Up to date, the overall efficiency of production of cloned embryos and offspring in livestock is estimated to be low. Further technical development of nuclear transplantation will enable large-scale production of cloned livestock and in near future the commercial cloning of animals will become a reality.

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Mechanical and elastic properties of vitrified radioactive wastes using ultrasonic technique

  • Sema Akyil Erenturk;Filiz Gur;Mahmoud A.A. Aslani
    • Nuclear Engineering and Technology
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    • v.56 no.2
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    • pp.472-476
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    • 2024

  • It is important that radioactive and nuclear wastes are immobilized in a glass composition with lower melting temperatures due to their economy. In this study, the elastic and mechanical properties of sodium borate-based vitrified radioactive waste were measured using ultrasonic techniques. Many ultrasonic parameters, such as elastic moduli, Poisson's ratio, and microhardness, were calculated by measuring the ultrasonic velocities of the glasses. The ultrasonic velocity data, the density, the calculated elastic moduli, micro-hardness, softening temperature, and Debye temperature depending on the glass composition were evaluated, and the relation with the structure was clarified. It was observed that the elastic modulus and Poisson ratio increased as the Cs2O content increased in glasses containing Cs waste. This result shows that the rigidity of the network structure of these glasses increases in contrast to the glass containing Sr.

  • https://doi.org/10.1016/j.net.2023.10.022 인용 PDF