| 摘要 |
PROBLEM TO BE SOLVED: To provide an MRI apparatus capable of suppressing the temperature change of a shim iron piece for magnetic field adjustment based on room temperature change and the heat generation of a gradient magnetic field coil, reducing the fluctuation of magnetic field strength and magnetic field uniformity and improving the resolution of images. SOLUTION: The magnetic resonance imaging apparatus comprises: a magnet for generating a static magnetic field in an imaging space; the gradient magnetic field coil for generating a gradient magnetic field in the imaging space; a shim iron piece for adjusting the uniformity of the static magnetic field; a shim tray for holding the shim iron piece by an optional distribution; a transmission coil of a high frequency for exciting magnetic resonance; a reception coil for receiving nuclear magnetic resonance signals from an object; and a temperature controller for controlling the shim iron piece and the shim tray to an optional temperature. Since the shim iron piece and the shim tray are controlled to the optional temperature, the temperature change of the shim iron piece for the magnetic field adjustment based on the room temperature change and the heat generation of the gradient magnetic field coil is suppressed. Thus, the fluctuation of he magnetic field strength and the magnetic field uniformity is reduced and the resolution of the images is improved as a result. COPYRIGHT: (C)2008,JPO&INPIT
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