| 摘要 |
PURPOSE: To provide a fluid flow sensing method that can easily measure the flow speed of the bloodstream in a blood vessel or an organ independently of the direction of the bloodstream. CONSTITUTION: Piezoelectric ultrasonic wave converting elements of two-dimensional arrangement to constitute a converter 110 are excited by a pulse of a constant period from a timer exciting circuit 116, and an ultrasonic wave is radiated to the artery 114, and when a focus of the spherical interrogation volume 112 is adjusted to the artery 114, particles of the bloodstream in the artery 114 scatter the ultrasonic wave backward. A Doppler detecting device 120 outputs a signal corresponding to a Doppler shift of a synthetic RF return signal R(t) from the synthetic RF return signal R(t) by combining individual RF signals from the respective piezoelectric ultrasonic wave transducing elements corresponding to backward scattering, and finds a band width by evaluating the signal corresponding to the Doppler shift by a band width detector 122, and finds a bloodstream characteristic as a prescribed function of the band width. |
