Magnetic resonance imaging device and imaging parameter determination method

A magnetic resonance imaging device comprising:

• a transmission coil that includes a plurality of channels that respectively transmit radio frequency pulses to a subject;
• a storage device which stores a database of data to calculate a specific absorption rate distribution for each of a plurality of predetermined subject models;
• and
• a processor programmed to determine a plurality of imaging parameters among imaging conditions used in imaging the subject, and execute imaging using the determined imaging parameters,
• wherein the processor is further programmed to:
• determine the imaging parameters to optimize a radio frequency magnetic field distribution in a region of interest while suppressing a maximum value of a local specific absorption rate to be equal to or smaller than a specific absorption rate threshold value using the data in the database, and
• wherein the imaging parameters includes a radio frequency magnetic field parameters which specify the radio frequency pulses to be transmitted through each of the plurality of channels and a specific absorption rate parameter which is different than the radio frequency magnetic field parameters and affects the specific absorption rate,
• wherein the processor is further programmed to:
• determine the radio frequency magnetic field parameters according to predetermined optimization conditions,
• calculate a specific absorption rate distribution using the determined radio frequency magnetic field parameters, a latest specific absorption rate parameter, and the data in the database when the radio frequency magnetic field parameters are determined,
• determine whether a maximum value of the calculated specific absorption rate distribution exceeds the specific absorption rate threshold value,
• when the maximum value exceeds the specific absorption rate threshold value, adjust the specific absorption rate parameter in a predetermined range,
• when the specific absorption rate parameter is changed, calculate the specific absorption rate distribution using the changed specific absorption rate parameter, determine whether a maximum value of the calculated specific absorption rate distribution using the changed specific absorption rate parameter exceeds the specific absorption rate threshold value, and
• repeats, when the maximum value of the specific absorption rate distribution exceeds the specific absorption rate threshold value, a process of changing a threshold value for regulating a uniformity condition in the optimization conditions by a predetermined value, a process of determining the radio frequency magnetic field parameter again, and a process of calculating the specific absorption rate distribution using the re-determined radio frequency magnetic field parameter, until the maximum value of the specific absorption rate distribution becomes equal to or smaller than the specific absorption rate threshold value.