New method for ultrasonic Doppler probe angle determination

A new method is described to determine the Doppler probe angle using a standard pulsed Doppler; the technique is based on the determination of vessel position with respect to the skin surface. The transit times of ultrasound waves toward the vessel from multiple probe positions on the skin, the distance between probe positions, and the probe-skin angle are measured. Using the probe-skin angle and the slope of the regression curve, the vessel-skin angle is determined trigonometrically. Experimental results show high accuracy within a vessel-skin angle range of 5-40 degrees.