effect in tissues maybe expressed as an equation as shown in Figure
1.6. Simply stated, the Doppler shift (Fd) of ultrasound will depend
on both the transmitted frequency (fo) and the velocity (V) of the
moving blood. This returned frequency is also called the "frequency
shift" or "Doppler shift" and is highly dependent upon the angle
(?) between the beam of ultrasound transmitted from the transducer
and the moving red blood cells. The velocity of sound in blood is
constant (c) and is an important part of the Doppler equation.