Patent ID: 8372008

Claim:
An ultrasound diagnostic apparatus comprising: an ultrasound probe including a plurality of ultrasound transducers configured to transmit ultrasound to a subject and configured to receive the ultrasound reflected by the subject to output an ultrasound detection signal; an optimum sound speed value determination device configured to determine an optimum sound speed value in a region of interest in the subject and optimum sound speed values at lattice points set in a region between the region of interest in the subject and the ultrasound probe on the basis of the ultrasound detection signal; a first arithmetical operation device configured to calculate a first received wave received from the region of interest on the basis of the optimum sound speed value in the region of interest when the ultrasound is transmitted to the region of interest; a second arithmetical operation device configured to set an assumed sound speed in the region of interest, and configured to calculate a second received wave received from the region of interest on the basis of the assumed sound speed and the optimum sound speed value at the lattice points when the ultrasound is transmitted from the ultrasound probe to the region of interest; and a local sound speed value determination device configured to make a determination of a local sound speed value in the region of interest on the basis of the first received wave and the second received wave.