A versatile test-object for the calibration of ultrasonic Doppler flow instruments.

Versatility in test-objects for ultrasonic Doppler units is desirable. The test-object described comprises a thin-walled plastic tube embedded in tissue-mimicking material. Blood is simulated using a mixture of water and glycerol with sephadex particles to act as scatterers. The test-object is suitable for use with a wide range of Doppler units which employ pulsed and continuous ultrasound in the frequency range 1 to 10 MHz. Calibration of several types of Doppler and imaging duplex systems has been performed for flow velocities up to 100 cm/s through a 10 mm tube. Above this velocity, for this tube dimension, turbulence occurs prevents the accurate measurement of flow velocity. The versatility of the test-object is further enhanced by the feasibility of manufacturing vessels of different shape and size. Slow flow through the tissue equivalent material may also be detected.