PURPOSE: To eliminate the distortion of a resonance image by detecting the ramp of the flat top part of a ramp magnetic field pulse from the frequency spectral shape of a nuclear magnetic resonace signal and controlling the output current waveform of a power source for a ramp magnetic field coil thereby controlling the ramp in the flat top part to a prescribed value or below.
CONSTITUTION: A measuring body is disposed in a static magnetic field. A high-frequency magnetic pulse (a) is passed to a high-frequency coil and the ramp magnetic field pulse (b) is passed to the ramp magnetic field coil. The intensity of the ramp magnetic field pulse is adequately selected as shown by (c) to excite the entire spin of the measuring body. A spin echo (d) is observed. The ramp in the flat top part of the ramp magnetic field pulse intensity is detected and the output electric power waveform of the power source for the ramp magnetic field coil for generating the ramp magnetic field is so controlled that the ramp thereof attains the prescribed value or below in accordance with the result of the detection. Since the ramp in the flat top part of the ramp magnetic field is decreased in the above-mentioned manner, the distortion and blur of the unclear magnetic resonance image is eliminated.
MORITA MASAO
YAMADA TADATOSHI
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