| 摘要 |
PROBLEM TO BE SOLVED: To discriminate between a higher harmonic component contained in a response signal of biological tissue and a higher harmonic component contained in a response signal of a contrast medium to extract both components. SOLUTION: In view of situation where the response signals of the contrast medium are distributed to a wide frequency band and the signal intensity is high, a transmission part has a function of transmitting an ultrasonic beam in the same direction at time intervals a plurality of times (M is the natural number≥2), while the ultrasonic signal of each time is formed of succeeding waveforms different in frequency, and the signal of each time is transmitted to be asymmetric with respect to inversion of polarity. A receiving part has a function of subjecting the response signals of the ultrasonic signals for the plural times (M) of ultrasonic signals to phasing processing to be added or subtracted to attenuate the response signal of biological tissue. Further, a band pass filter 34 for the response signal is provided, the band width thereof is variably set within a range from 0.0f<SB>0</SB>to 0.4f<SB>0</SB>, or set to 0.8-1.8f<SB>0</SB>, preferably set to 1.2-1.8f<SB>0</SB>, and further variably set according to the depth of a response signal within a range of 0.8-1.8f<SB>0</SB>. COPYRIGHT: (C)2009,JPO&INPIT
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