Performance tests of Doppler ultrasound equipment with a string phantom

A detailed testing protocol has been developed for string phantom quality assessment performance measurements of Doppler equipment. General procedures have been developed for accurate setup of the string phantom prior to measurements, independent calibration of the string velocity, and compensation for degassed water in the tank. Detailed testing procedures were developed for important Doppler parameters. The dependence of spectral broadening on Doppler angle is demonstrated and a procedure given for minimizing its effect on Doppler velocity measurements. Doppler velocity calibration to better than 4% has been demonstrated even with degassed water in the tank with six high quality commercial pulsed Doppler systems.