| 摘要 |
A method and apparatus for aiming a pulse Doppler flow sensing device are presented. The Doppler flow device transmits ultrasonic energy in a wide beam which uniformly encompasses a blood vessel and receives the reflected ultrasonic energy in the same wide beam and also in a beam which is small enough to be placed within the blood vessel. When the beams are concentric with the blood vessel, the device is correctly placed. A processor/controller process the received reflected Doppler energy and calculates the maximum and mean blood velocities from both beams. It also tests whether the blood velocities satisfy predetermined criteria. If the criteria are satisfied, the Doppler device is properly aligned with the blood vessel and the measurement is valid.
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