[The Doppler Simulator DS 81. A new calibration method for ultrasound-cw-Doppler blood flow measurement devices]

Quality assurance in commercial cw-Doppler devices demands the use of special techniques in providing reproducible, optimized patient examination conditions for the individual instrument, and to permit a comparison with results obtained by other equipment. Equipment can be tested on two different technical levels: by checking the total performance by means of a Doppler phantom, or by testing the relevant components by means of electrical test signals. The use of Doppler phantoms involves certain drawbacks with respect to some equipment parameters and the routine equipment check. In the German Federal Republic, new official regulations (KBV), including the minimum requirements for Doppler equipment have been issued. To fulfil the legal requirements, a special test device, The Doppler Simulator DS 81 (1981), has proved suitable. The device provides a graduated scale of discrete, synthetic Doppler frequencies; these are fed into the Doppler equipment under test, and the response is recorded on the instrument's strip chart recorder or viewing screen. They are used as reference frequencies and for calibration. This method represents a further step towards reproducible or quantitative Doppler sonography.