Which statement is true about deeper imaging?

Which statement is true about deeper imaging?

• A. It uses shorter PRP.
• B. It uses higher PRF.
• C. It uses lower duty factor.
• D. It uses longer PRP and lower PRF.

Answer: (D)

When imaging deeper tissues, you must give enough time for echoes to return before sending the next pulse. That means increasing the time between pulses, known as the pulse repetition period. Since pulse repetition frequency is the reciprocal of the PRP, making PRP longer automatically lowers the PRF. A longer PRP with the same pulse duration also reduces the duty factor (the fraction of time the system is emitting energy), which helps keep energy exposure appropriate while still allowing deep echoes to be captured. So the true statement is that deeper imaging uses a longer PRP and a lower PRF. Shortening the PRP or boosting the PRF would shorten the listening window and hinder detection of deep echoes. Lowering the duty factor can occur as a consequence of a longer PRP, but it doesn’t by itself define deeper imaging—the critical elements are the longer PRP and the resulting lower PRF.

When imaging deeper tissues, you must give enough time for echoes to return before sending the next pulse. That means increasing the time between pulses, known as the pulse repetition period. Since pulse repetition frequency is the reciprocal of the PRP, making PRP longer automatically lowers the PRF. A longer PRP with the same pulse duration also reduces the duty factor (the fraction of time the system is emitting energy), which helps keep energy exposure appropriate while still allowing deep echoes to be captured. So the true statement is that deeper imaging uses a longer PRP and a lower PRF.

Shortening the PRP or boosting the PRF would shorten the listening window and hinder detection of deep echoes. Lowering the duty factor can occur as a consequence of a longer PRP, but it doesn’t by itself define deeper imaging—the critical elements are the longer PRP and the resulting lower PRF.