Final answer:
To reduce low level echoes on a Doppler image, the gain control must be decreased to decrease the amplification of received echoes, enhancing the clarity of the image. Modifying the Doppler scale and baseline can also aid in managing signal processing. Additionally, measuring beat frequency helps to accurately depict the velocity of moving reflectors for an improved Doppler image.
Step-by-step explanation:
To reduce low level echoes on a Doppler image, one can adjust the gain controls. The gain control, sometimes called sensitivity, amplifies the received echoes. By decreasing the gain, lower level echoes can be minimized, making it easier to interpret the movement of blood within blood vessels. Also, specific Doppler controls like the scale (velocity range) and the baseline can help manage how the Doppler signals are processed and displayed, potentially reducing the appearance of low level echoes.
It's also worth mentioning that a technique used for measuring the Doppler shift in an echo involves contrasting the frequency of echoed sound with the original broadcast frequency, thus creating beats. The beat frequency provides a clearer indication of the velocity of the moving reflector, such as red blood cells, helping to create a more accurate image.