Purpose: To design, evaluate, and apply a bow tie antenna transceiver radiofrequency (RF) coil array tailored for cardiac MRI at 7.0 Tesla (T).
Methods: The radiofrequency (RF) coil array comprises 16 building blocks each containing a bow tie shaped λ/2-dipole antenna. Numerical simulations were used for transmission field homogenization and RF safety validation. RF characteristics were examined in a phantom study. The array's suitability for high spatial resolution two-dimensional (2D) CINE imaging and for real time imaging of the heart was examined in a volunteer study.
Results: The arrays transmission fields and RF characteristics are suitable for cardiac MRI at 7.0T. The coil performance afforded a spatial resolution as good as (0.8 × 0.8 × 2.5) mm(3) for segmented 2D CINE MRI at 7.0T which is by a factor of 12 superior versus standardized protocols used in clinical practice at 1.5T. The proposed transceiver array supports 1D acceleration factors of up to R = 6 without impairing image quality significantly.
Conclusion: The 16-channel bow tie antenna transceiver array supports accelerated and high spatial resolution cardiac MRI. The array is compatible with multichannel transmission and provides a technological basis for future clinical assessment of parallel transmission techniques at 7.0 Tesla. Magn Reson Med 75:2553-2565, 2016. © 2015 Wiley Periodicals, Inc.
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http://dx.doi.org/10.1002/mrm.25840 | DOI Listing |
Sensors (Basel)
January 2025
Department of Optoelectronics, Center for Physical Sciences and Technology (FTMC), Saulėtekio Ave. 3, LT-10257 Vilnius, Lithuania.
The practical implementation of terahertz (THz) imaging and spectroscopic systems in real operational conditions requires them to be of a compact size, to have enhanced functionality, and to be user-friendly. This work demonstrates the single-sided integration of Fresnel-zone-plate-based optical elements with InGaAs bow-tie diodes directly on a semiconductor chip. Numerical simulations were conducted to optimize the Fresnel zone plate's focal length and the InP substrate's thickness to achieve constructive interference at 600 GHz, room-temperature operation and achieve a sensitivity more than an order of magnitude higher-up to 24.
View Article and Find Full Text PDFMaterials (Basel)
January 2025
Department of Industrial Engineering, University of Trento, 38123 Trento, Italy.
The metastable β-Ti21S alloy exhibits a lower elastic modulus than Ti-6Al-4V ELI while maintaining high mechanical strength and ductility. To address stress shielding, this study explores the integration of lattice structures within prosthetics, which is made possible through additive manufacturing. Continuous adhesion between the implant and bone is essential; therefore, auxetic bow-tie structures with a negative Poisson's ratio are proposed for regions under tensile stress, while Triply Periodic Minimal Surface (TPMS) structures with a positive Poisson's ratio are recommended for areas under compressive stress.
View Article and Find Full Text PDFRisk Manag Healthc Policy
December 2024
Belt and Road Initiative Center for Chinese-European Studies (BRICCES), Guangdong University of Petrochemical Technology, Maoming, People's Republic of China.
Introduction: Psychosocial risks (PSRs) are identified as one of the main modern occupational safety issues, primarily related to occupational stress, and need to be reduced to safe levels in accordance with international requirements. The research purpose is to improve the process of managing the PSRs in the occupational safety and health management systems of employees, taking into account the impact of psychosocial dangers in accordance with the requirements of ISO 45001:2018 and ISO 45003:2021 standards.
Methods: To develop the process of managing the PSRs, a system analysis method is applied, which allows determining the structural relationships between the variable elements of dangerous psychosocial factors described in the ISO 45003:2021 standard.
The compression and integration of nonlinear optical processes to the nanoscale are expected to have significant implications for quantum optics, biology, and medicine. In this work, a composite metasurface consisting of a hollow-bow-tie-shaped metal metasurface and a patterned amorphous silicon metasurface is proposed. An external terahertz (THz) electric field enhanced by the hollow-bow-tie structure is employed to break the centrosymmetry, which allows the generation of optical second harmonic.
View Article and Find Full Text PDFQual Manag Health Care
October 2024
Author Affiliations: School of Management, Tianjin University of Technology, Tianjin, China (Dr Zhao); and College of Tourism and Service Management, Nankai University, Tianjin, China (Dr Liu).
Background And Objectives: Medical risks are considered to endanger patients and impact the health care system. Such iatrogenic risks necessitate hospitals taking a more proactive method to quantitatively analyze medical risk, and then to implement more targeted precautions. To address this problem, a novel quantitative risk assessment framework is proposed and further applied in radiotherapy risk assessment.
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