In physics, the Doppler effect describes the change in frequency or wavelength of a wave in relation to an observer who is moving relative to the wave source. When the source and observer are moving closer, the frequency appears higher (shorter wavelength), and when they are moving apart, the frequency appears lower (longer wavelength). This fundamental principle is widely applied in various scientific and engineering fields.
In medical ultrasound, the Doppler effect is crucial for non-invasively assessing blood flow. Ultrasound transducers emit sound waves that reflect off moving red blood cells, and the change in frequency of these reflected waves indicates the direction and velocity of blood flow. This allows clinicians to diagnose conditions such as stenosis, thrombosis, and valvular heart disease, providing vital real-time diagnostic information.
