Doppler tomography was performed in phantoms in which fluid was flowing in several tubes. The backscatter continuous wave Doppler signal from a 2-MHz carrier was measured for 128 samples along 200 profiles taken at equispaced angles of view around the phantom. The RF signal was mixed to base band, low-pass filtered, and A/D converted at 10 kHz for subsequent computer analysis. The Doppler power in a specified frequency band was used to estimate number of particles moving within a certain velocity range. Reconstructed images were obtained with and without flow in tubes within excised human breast. Images proportional to number of particles flowing at velocities greater than a certain velocity were of good quality.
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