Browsing by Subject "Internal coils"
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Item Open Access Design and implementation of internal MRI coils using ultimate intrinsic(Bilkent University, 2006) Eryaman, YiğitcanIn this thesis, methods for optimization of internal magnetic resonance imaging coils have been developed. As a sample optimization endorectal coils were optimized. As the first step ultimate intrinsic signal-to-noise ratio for internal coils was formulated. This value was used as a measure of performance of the internal MRI coils. The related optimization problem was divided into two sub problems: length optimization and cross-sectional optimization. For the length optimization length of a single loop rectangular coil was optimized in order to obtain maximum intrinsic signal to noise ratio at the prostate region. For the cross-sectional optimization designs with different cross-sectional geometries were implemented and tested in saline solution phantom. The designs that gave a significant improvement over the conventional loop coil were favored and the related design ideas were used for the design of an optimized coil. Finally optimized coil was tested in a saline solution phantom model and its performance was calculated.Item Open Access Evaluation of internal MRI coils using ultimate intrinsic SNR(John Wiley & Sons, 2004) Çelik, H.; Eryaman, Y.; Altıntaş, A.; Abdel-Hafez, I. A.; Atalar, ErginThe upper bounds of the signal-to-noise ratio (also known as the "ultimate intrinsic signal-to-noise ratio" (UISNR)) for internal and external coils were calculated. In the calculation, the body was modeled as a dielectric cylinder with a small coaxial cylindrical cavity in which internal coils could be placed. The calculated UISNR values can be used as reference solutions to evaluate the performance of internal MRI coils. As examples, we evaluated the performance of a loopless antenna and an endourethral coil design by comparing their ISNR with the UISNR.