Ultrasonic pulse Doppler tomography is generally applied to noninvasiv
e vascular measurement. The present method, however, measures only one
component along the beam direction of a three-dimensional (3-D) veloc
ity vector and provides useful information only if the beam direction
in relation to the flow velocity is known is known, Images obtained by
such systems are not only unsuitable for quantitative evaluation. and
but also prone to misinterpretation. On the other hand, in terms of r
eal-time data acquisition achieved by scanning 3-D space, a two-dimens
ional (2-D) array probe is expected to become indispensable for future
clinical applications. From this point of view, we have proposed a me
thod of measuring a 3-D velocity vector using the 2-D array probe. In
this paper, the principles of the proposed approach are introduced and
experimental data obtained using a prototype system and the now phant
om are processed. Experimental results validate the usefulness of the
method and its potential for practical use.