Daiki Tamada

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The screening current induced in a bulk superconductor presents a critical problem for gradient coil design because it gives rise to undesirable effects on the gradient field: namely, a decrease in the efficiency and a distortion of the field. In this paper, a new coil design method for the bulk magnet is proposed using the finite-difference method (FDM)(More)
We developed an adaptive optics (AO) retinal scanner by using a light source with a center wavelength of 1-microm. In a recent study on optical coherence tomography (OCT), it was proved that 1-microm light provided higher image contrast of deep region of the eye than 840-nm light. Further, high lateral resolution retinal images were obtained with AO. In(More)
A compressed sensing method using a cross sampling and self-calibrated off-resonance correction is proposed. Estimation of the magnetic field inhomogeneity based on image registration enables the off-resonance correction with no additional radio-frequency pulses or acquisitions. In addition to this advantage, a fast and straightforward calculation was(More)
MRI may be a noninvasive and alternative tool for skeletal age assessment in children, although few studies have reported on this topic. In this article, skeletal age was assessed over a wide range of ages using an open, compact MRI optimized for the imaging of a child's hand and wrist, and its validity was evaluated. MR images and their three-dimensional(More)
We adopted a combination of pieces of permanent magnets and a single-channel (SC) shim coil to shim the magnetic field in a magnetic resonance imaging system dedicated for skeletal age assessment of children. The target magnet was a 0.3-T open and compact permanent magnet tailored to the hand imaging of young children. The homogeneity of the magnetic field(More)
A superconducting bulk magnet composed of six vertically stacked annular single-domain c-axis-oriented Eu-Ba-Cu-O crystals was energized to 4.74 T using a conventional superconducting magnet for high-resolution NMR spectroscopy. Shim coils, gradient coils, and radio frequency coils for high resolution NMR and MRI were installed in the 23 mm-diameter(More)
PURPOSE To examine the feasibility of accelerating magnetic resonance (MR) image acquisition for children using compressed sensing (CS). Skeletal age assessment using MRI sometimes suffers from motion artifacts because of the long scan time in children. Reducing image acquisition time may provide benefits by reducing motion artifacts, increasing efficiency(More)
A temperature variable magnetic resonance imaging (MRI) system has been developed using a 1.0 T permanent magnet. A permanent magnet, gradient coils, radiofrequency coil, and shim coil were installed in a temperature variable thermostatic bath. First, the variation in the magnetic field inhomogeneity with temperature was measured. The inhomogeneity has a(More)
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