Patent ID: 8115486

Claim:
A magnetic resonance imaging apparatus comprising an irradiating means for irradiating magnetic field pulses comprising a gradient magnetic field and a radio frequency pulse on a test subject, a non-transitory waveform controlling means for calculating a radio frequency pulse waveform for realizing an ideal spatial irradiation pattern and applying a radio frequency pulse of the calculated waveform to the irradiating means, and an imaging means for processing nuclear magnetic resonance signals generated by the test subject upon irradiation of the magnetic field pulses to perform imaging, wherein: the non-transitory waveform controlling means comprises: a first memory means which memorizes multiple radio frequency pulse waveform vectors, and a calculating means for reading out a radio frequency pulse waveform vector from the memory means to calculate a simulated irradiation pattern and calculating a radio frequency pulse waveform which gives a minimum weighted sum of squares of differences of absolute values and squares of differences of phases between the ideal spatial irradiation pattern and the simulated irradiation pattern according to min x ⁢ { λ ⁢ ∑ i ⁢ {  m i  -  f i ⁡ ( x )  } 2 + χ ⁢ ∑ i ⁢ { ∠ ⁢ ⁢ m i - ∠ ⁢ { f i ⁡ ( x ) } } 2 + ( 1 - λ - χ ) ⁢  x  2 2 } . ( 1 ) where the radio frequency pulse waveform is represented by x, the ideal spatial irradiation pattern is represented by m and the simulated irradiation pattern is represented by f(x), and λ, χ and (1−λ−χ) are weighting parameters.