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Magnetic resonance imaging (MRI) is widely used in human breast cancer detection, and the advancement of the radio-frequency (RF) phased-array technology promises to further improve the diagnostic image quality. In this paper, an inverse design method is presented for the theoretical design of an ellipsoidal RF phased array coil for human breast MRI. The target field technique was used to analytically...
In this study, three types of radio-frequency shields are studied and compared in the context of ultra-high field small-animal magnetic resonance imaging. It has been demonstrated that the coil penetration depth and mutual coupling between the coils depend heavily on the type of shield employed. The results were used to guide the design of a 9.4T 8-element transceive small animal array, which provides...
We present a numerical investigation of the RF fields generated inside a human head by single and dual-row loop arrays. For a uniform circular polarization (CP) mode excitation, a dual-row array has no advantage for human brain excitation. Significant improvement of B1+ homogeneity with a simultaneous increase of coverage in the axial direction can be obtained by using a dual-row array together with...
A shielded, non-overlapped 9.4T 8-element transceive volume array was designed and constructed for small animal MRI studies. The coil configuration was optimized to obtain an appropriate trade-off between coil sensitivity, field penetration, and mutual decoupling. The simulated and experimental results presented herein demonstrate that the new volume array is capable of offering higher RF penetration,...
In this study, an electromagnetics-based inverse sensitivity mapping method is introduced for applications in high field MRI. Instead of using simplistic numerical approximations, the sensitivity of the radio-frequency coil was determined through a field approach by using iterative optimization. The current study is an extension to previous studies on the inverse method, which has restricted itself...
A small, hermetic, wirelessly-controlled retinal prosthesis was developed for pre-clinical studies in Yucatan mini-pigs. The device was implanted on the outside of the eye in the orbit, and it received both power and data wirelessly from external sources. The prosthesis drove a sub-retinal thin-film array of sputtered iridium oxide stimulating electrodes. The implanted device included a hermetic titanium...
Combining single coils to form a coil array provide advantages for magnetic induction measurements of breathing or heart activity. The main goal for such combination could be a coil configuration which makes the whole measurement system less sensitive for moving artifacts of the patient due to the capability of using many coils for signal acquisition. Such setup could be designed and tested with FEM...
A small, hermetic, wirelessly-controlled retinal prosthesis was developed for pre-clinical studies in Yucatan mini-pigs. The device was implanted on the outside of the eye in the orbit, and it received both power and data wirelessly from external sources. The prosthesis drove a sub-retinal thin-film array of sputtered iridium oxide stimulating electrodes. The implanted device included a hermetic titanium...
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