The sonographer can change pulse repetition frequency by adjusting which parameter?

• A. Depth of view of a scan
• B. Gain
• C. Time gain compensation
• D. Frequency

Answer: (A)

Pulse repetition frequency is how often ultrasound pulses are emitted. The rate is determined by the time needed for a pulse to travel to the deepest part of the image and back. When you set a deeper depth of view, echoes take longer to return, so the system spaces pulses farther apart to avoid overlap, which lowers the PRF. Conversely, shallower imaging shortens the round-trip time and allows pulses to be sent more frequently, increasing the PRF. So adjusting depth of view directly changes PRF.

Gain and time gain compensation affect signal brightness, not how often pulses are emitted. They modify amplification at various depths, not the emission rate. Frequency changes the transmitted wavelength and affects resolution and penetration, but it does not set the pulse emission rate like depth does.