One of the most important applications of Doppler theory in the medical field is to identify the nature of fluid flow, and in the medical field, it is blood flow. The applications of echo and the use of special materials in transmitting frequencies through electrical physical materials, known as transducers, which have the properties of receiving, transmitting, converting acoustic dynamic energies and re-transmitting them electrically.

Doppler; Echo Planar; Imaging; Physical Principles; Application.