As one of the most advanced non-destructive analytical techniques for nuclear wastes, tomographic Gamma Scanning (TGS) is able to give accurate quantitative and qualitative measurements of nuclear waste barrels. OSEM (Ordered Subsets Expectation Maximization) has been used in transmission TGS image reconstruction on account of its good reconstruction quality and ideal convergence rate. In this paper, an improved method-NMO-OSEM (Non-minimization optimization OSEM) was proposed, it's an iterative algorithm with corrected initial values optimized by non-minimization optimization method. To evaluate its performance, a TGS system is used to perform transmission measurements on barreled nuclear wastes. The results show: ①Compared with the reconstructed images by traditional OSEM under 6 transmission energies (122 keV, 344 keV, 779 keV, 964 keV, 1112 keV, 1408 keV), the improved NMO-OSEM has a great advantage in reducing the artifacts and effectively improving the quality of the reconstructed images. ②the attenuation coefficients values of 72 voxels under 3 emission energies (662 keV, 1173 keV and 1332 keV) reconstructed by the proposed algorithm are more accurate (range of error: 0.22%-13.83%) than reconstructed by traditional OSEM (range of error: 1.31%-32.21%), which proves this method has more stable reconstruction precision and could be regarded as an ideal option for real applications.
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http://dx.doi.org/10.1016/j.apradiso.2018.09.001 | DOI Listing |
Biomed Phys Eng Express
January 2025
Mindanao Radiation Physics Center, MSU-Iligan Institute of Technology, Andres Bonifacio Street Tibanga, Iligan City, Lanao Norte, 9200, PHILIPPINES.
To accurately model and validate the 6 MV Elekta Compactlinear accelerator using the Geant4 Application for Tomographic Emission (GATE). In particular, this study focuses on the precise calibration and validation of critical parameters, including jaw collimator positioning, electron source nominal energy, flattening filter geometry, and electron source spot size, which are often not provided in technical documentation. Methods: Simulation of the Elekta Compact6 MV linear accelerator was performed using the Geant4 Application for Tomographic Emission (GATE) v.
View Article and Find Full Text PDFAppl Radiat Isot
December 2024
Department of Radiological Science, Gachon University, 191, Hambakmoero, Yeonsu-gu, Incheon, Republic of Korea. Electronic address:
The purpose of this study was to propose and evaluate an algorithm that maximizes the image quality of gamma-ray images using a cadmium zinc telluride (CZT) photon-counting semiconductor detector (PCSD) under thin detector thickness conditions. In addition to the CZT PCSD, a pixel-matched parallel-hole collimator that can optimize the spatial resolution of gamma-ray images was modeled. A non-local mean (NLM) noise reduction algorithm was applied to the acquired images using Geant4 Application for Tomographic Emission platform to quantitatively evaluate the overall image quality improvement.
View Article and Find Full Text PDFACS Omega
November 2024
Radiochemistry Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400085, India.
Insufficient inventory control arising from inadequate monitoring procedures can lead to vulnerabilities in nuclear security. In addition, insider threats, by either malicious intent or negligence, can pose a substantial risk by exploiting such deficiencies to perform unlawful actions, such as theft or diversion, which may lead to compromised nuclear security. Interim storage barrels, intended for temporary containment of low-density nuclear waste, require special attention in this regard.
View Article and Find Full Text PDFBr J Ophthalmol
September 2024
Beijing Institute of Ophthalmology, Beijing Tongren Hospital, Capital Medical University, Beijing Ophthalmology and Visual Sciences Key Laboratory, Beijing, China
Biomed Phys Eng Express
September 2024
Fox Chase Cancer Center, Temple University Health System, 333, Cottman Avenue Philadelphia, PA, 19111, United States of America.
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